Semester 2 physics 09 10 by xiaoyounan

VIEWS: 11 PAGES: 168

									Semester 2 Chem/Phys
     2008-2009

     Mrs. Eglite




                       1
2
Name: _____________________________________

Stamp Sheet
                                       Date turned in ___________ Total: ___________

     1           2            3               4                5




     6           7            8               9               10




                              Date turned in ___________ Total: ___________


     1           2            3               4                5




     6           7            8               9               10




                                                                                  3
Name: _____________________________________

Stamp Sheet
                                       Date turned in ___________ Total: ___________

     1           2            3               4                5




     6           7            8               9               10




                              Date turned in ___________ Total: ___________


     1           2            3               4                5




     6           7            8               9               10




                                                                                  4
Name: _____________________________________

Stamp Sheet
                                       Date turned in ___________ Total: ___________

     1           2            3               4                5




     6           7            8               9               10




                              Date turned in ___________ Total: ___________


     1           2            3               4                5




     6           7            8               9               10




                                                                                  5
6
       12:00




9:00           3:00




       6:00




                      7
       12:00




9:00           3:00




       6:00




                      8
                  RULES
Electricity

Waves and sound

Color

Light




                          9
Series:
   What happens to the resistance of a circuit when a resistor is added in series? Why does this happen?


   Draw a circuit diagram of a circuit that has two resistors (one 100 ohms the other 300 ohms) in series.




   What is the total resistance in the circuit diagram you drew? How did you calculate it?




   What happens to the current of a circuit when a resistor is added in series? Why does this happen?




   What equation exists that will allow you to calculate the current of a circuit given the voltage and the
    resistance of the circuit. Give an example of this relationship using a circuit diagram and labeling the
    voltage, current, and resistance.




Parallel:
   What happens to the resistance of a circuit when a resistor is added in parallel? Why does this happen?



   What happens to the current of a circuit when a resistor is added in parallel? Why does this happen?


   Draw a circuit diagram of a circuit that has a 9 volt battery and two resistors (one 100 ohms the other
    300 ohms) in parallel.




   What is the total current in the circuit diagram you drew? How did you calculate it (show the equation
    you used and steps you took to solve it)?


   How does your equation to find the current in a parallel circuit change when each additional branch is
    added? How does this mathematically prove what you said about how the current changes when you
    add a resistor to the circuit in parallel?




                                                                                                               10
                           Waves and sound rule
1.   What are the two major types of waves?
           a. Give an example of each




2. What is the relationship between frequency and wavelength?


3. Give three examples of mediums



4. Draw a wave with an amplitude of 6 cm and a period of 4sec (draw 2 cycles).



5. Draw an example of two waves demonstrating constructive interference




6. Draw the 4th harmonic with a wavelength of 4meters-lable a node and anti-node



7. Describe how we interpret different pitches




8. A wave has a period of 6 seconds and wavelength of 4 meters. What is the frequency? What is the
   speed of the wave?




                                                                                                 11
12
13
14
15
16
Freshman Physics         Name:_______________________________________ Per:____
Vocab: Electrostatics and Circuits            Due Date:_______________________

INTRO: To develop a true understanding of electrostatics and all types of circuitry it is
important to understand the vocabulary that is used to describe these concepts. You can find
these nomenclature terms in Ch 9 and Ch13-15.

Vocab:
Atomic Theory:



Electromagnetic force:



Strong Nuclear force:



Weak Force:



Electric Current:



Electric Circuit:



Resistor:



Ampere:



Voltage (include what a volt is):




Voltmeter:
Multimeter:




                                                                                           17
Battery:



Ammeter:



Resistance:



Ohm:



Ohm’s Law:



Potentiometer:



Series Circuit:



Parallel Circuit:



Short Circuit:



Kilowatt:



Direct Current:


Alternating Current:




                       18
Transformer:



Coulomb:



Static Electricity:



Coulomb’s Law:



Electroscope:



Polarized:



Capacitor:




                      19
20
21
22
                                         How to use a Multimeter

Measuring Voltage

           The red lead must be plugged into the port marked with Volts (V)
           The multimeter dial must be turned to Volts (direct current)
           To measure voltage, place the leads on either side of the battery or resistor (light bulb). See
            example in diagram below:




                                 +                             This is how you
                                                               measure voltage
                                                               across the battery.




                                                                 This is how you
  +                                                              measure voltage
                                                                 across a light bulb.




Measuring Current
      The red lead must be plugged into the port marked with Amps (A)
      The multimeter dial must be turned to Amps.
      To measure current, the multimeter must be part of the circuit. See example in diagram
         below.


                                                       Example of how to measure current
                                                       before a light bulb.
      +
                                                       Multimeter must be part of the circuit.

                                                       Red lead must be in port to measure
                                                       Amps.



                                                                                                              23
                                    Electricity Basics
   Voltage                                                           Current




Introduction
   We use electricity every day, almost every minute. Furthermore, electrical devices use energy. They
   get the energy from the current that flows through them. When designing an electrical device, or an
   electric circuit, it is important for the proper amount of current to flow for the voltage that will be
   applied. In this lab, you will build circuits and learn about voltage (volts) and current (amps) which
   are fundamental quantities that describe the electricity we use. You will then investigate resistance,
   which is the property that relates current and voltage in a circuit or electrical device.
Objectives: After today, you should be able to: get a light bulb to light up on your own, draw a picture
of what a light bulb looks like on the inside, define and give examples of conductors and insulators.

NOTE: NEVER HOOK A BATTERY UP TO ITSELF!!!!!

Part 1                  making a bulb light
   1. Using one battery, the wires, one bulb (with bulb socket) and the circuit board, build a simple
      circuit so that the bulb will light.
      For describing electric circuits we use the language of circuit diagrams. In a circuit diagram,
      wires are represented by solid lines. Electrical devices
      like batteries, switches, and bulbs are represented by
      symbols.

        Using the appropriate symbols, draw a diagram of the
       circuit you just built (minus the circuit board).




b) How can you tell electric current is flowing in the circuit?


c) Can you see the current flow?




                                                                                                        24
d) If current flows from positive to negative, draw arrows in your picture above to represent the current
flow through your circuit.

e) Why might the word ―closed‖ be the best choice to describe your set up?


2. Add a switch to your set up such that when the switch is open, the bulb does not light, and when the
switch is closed, the bulb lights.
a) How does the switch affect the current‘s flow?


b) Why does the bulb go out when you open the switch?




                 Time for a class discussion!



                         ENERGY FLOW DIAGRAM




                                                                                                       25
Part 2: Conductors & Insulators
   Materials in which electric current flows easily are called conductors and materials that current does
   not flow through easily are called insulators.
     1.    Break one connection in your one-bulb circuit by moving wires to different metal posts,
           leaving an ―open circuit‖ (see picture below).
     2.    Complete the circuit by touching different materials (in the data table) between the wire and
           the post. Record your observations as to which materials allow the bulb to light and which do
           not. Also, put a check mark next to the material(s) that allow the bulb to light the brightest.
           Put a ―0‖ next to the material(s) that barely made the bulb light up.




          copper wire                                     plastic straw
            steel nail                                        string
       magnesium ribbon                                   rubber band
           paper clip                                        marker


b) What characteristics are shared by the conductors you found?



c) What characteristics are shared by the insulators you found?




          Let’s chat before we move on…




                                                                                                       26
Part 3                 Measuring the Voltage of a Battery
Notes on how to use a multimeter:

        Turn the dial of your multimeter to DC volts (or
        VDC). Red goes to the positive terminal and
        black to the negative terminal. Touch two points
        in a circuit with the leads and the meter reads the
        voltage between the two points.

1.
     a) What is the voltage reading on the actual battery? ________

     b) What is the voltage reading on the multimeter? _________

     c) Why might the numbers from a and b be slightly different?

2. Take a second battery and connect it to the first by touching the ends together. Measure and record
the voltage for the 4 possible ways to connect the two batteries.

     a) + to + ___________
     b) + to - ___________
     c) - to + ____________
     d) - to - _____________

3. How do the readings for b and c compare to the voltage reading for just 1 battery?



4. How can you explain the differences in voltage for b and c compared to the voltage reading for a and
d?




              Let’s talk…Shall We?




                                                                                                         27
Part 4: Measuring current
  To measure current, the meter must be connected so the current has to flow through it. This is
  different from voltage measurement. To measure current you must force the current to flow through
  the meter by eliminating all other paths the current could go. Follow the instructions below
  carefully. Too much current can damage the meter.




      3.   Set the multimeter to measure current (or A AC/DC). You might have to use the milliamps
           (mA) setting on the multimeter.
      4.   Open the switch and touch the red lead of the meter to the metal part of the switch closest to
           the battery‘s positive terminal (+).
      5.   Touch the black lead of the meter to the metal part on the other side of the switch.
      6.   The bulb should light, showing you that current is flowing through the meter. If the bulb does
           not light, current can still be flowing, but in a small amount. The meter should display the
           current in amps or milliamps, depending on the setting you‘ve chosen. This is the total
           current flowing around the circuit carrying power from the battery to the bulb.
      7.   Record how much current is flowing in the circuit. Watch your units!
                                                            Current is _______________________
  
  
  




                                                                                                      28
Finding Voltages in Series
       Materials
       :2 D-cell batteries
       3 2.5-volt bulbs
       4 wires
       multimeters
       3 bulb holder

Notes about circuits set up in series: Series means that all items in a circuit are set up in ONE
continuous loop ONLY. If you see more than one loop, you do NOT have a series circuit. Refer to the
previous multi-battery lab if you need to. All of those circuits were series circuits because they had only
one loop. Make sure you are now using the proper circuit diagram symbols.
Circuit 1
1) Build a circuit so it has one bulb that is lit using one battery. Draw a circuit diagram for the circuit.




a) Use the multi meter to measure the voltage of the bulb. V= ___________

b) Use the multi meter to measure the voltage of the battery. V= ____________

c) What do you notice about the voltage of the battery compared to the voltage of the bulb?


Circuit 2
2) Build a circuit so that it has TWO bulbs that are connected in series (ONE continuous loop) using
   one battery. Draw a circuit diagram for the circuit.




3) Use the multi meter to measure the voltage of each bulb individually.
   V (bulb 1) = ___________
   V (bulb 2) = ___________




                                                                                                         29
4) Use the multi meter to measure the voltage of the battery.
   V (battery 1) = ___________
   V (battery 2) = ___________

5) How does the total voltage of bulb one and two compare to the total voltage of batteries 1 and 2?


Circuit 3
6) Build a circuit so that it has THREE bulbs that are connected in series (ONE continuous loop)
   using two batteries. Draw a circuit diagram for the circuit.




7) Use the multi meter to measure the voltage of each bulb individually. Record these values next to
   the corresponding bulb in the third circuit diagram.

8) Use the multi meter to measure the voltage of the battery. Record this value next to the
   corresponding battery in your circuit diagram.




SUMMARY QUESTIONS
1) Knowing what you do about the insides of bulbs, if one of the bulbs burned out in the three-bulb
   series circuit, would the rest stay lit or would they go out? Support your answer with evidence.




2) Compare the voltage of the bulb in the circuit #1 to the voltage of the same bulb when you added a
   second bulb in circuit #2. Did the voltage of bulb increase, decrease, or not change?


3) Explain why you think this happened. Support your answer with evidence.




4) Compare the voltage of the 2 bulbs in the circuit #2 to their voltages when you added a third bulb in
   circuit #3. Did the voltages of bulbs increase, decrease, or not change?




                                                                                                       30
5) Explain why you think this happened. Support your answer with evidence.




6) What can you conclude about the total voltage of the battery(s) compared the voltage of the bulbs in
   the circuit?



7) If you had 6 identical bulbs hooked up in series with an 18v battery, predict the amount of voltage
   each bulb would receive. Explain the evidence from this lab that leads you to that prediction.




        Checkpoint




                                                                                                         31
Please work in pencil!!!
The Introduction:
At the end of this lab you will be able to define voltage, current, and resistance. You will discover the
physical relationship between resistance and current in a series circuit. You will also create a
mathematical formula relating to voltage, current and resistance in a series circuit.

The Problem:
      If more resistance is added to a series circuit, what will happen to the total current of the
      circuit?

The Materials:
     You will need to go to www.explorelearning.com and log in.

       Launch the gizmo called ―Circuits‖.

       In the website you will ONLY use the following equipment:
               1 10 volt battery
               4 resistors (10ohms, 20ohms, 100ohms, 200ohms)(there are lots of each—if you drag one
               of them over to your set up, you will see that there are still more that you can drag)
               the ammeter (the green circle marked with an ―A‖ sitting on the ―meters‖
                shelf)
               a shelf full of wires

The Procedure:
       What are the two variables in your experiment?


           Which is the independent (manipulated) variable?


           Which is the dependent variable?




           Stop: Let’s make sure that we all agree about the independent and
           dependent variables. Also, let’s set up the first 2 circuit diagrams together.




                                                                                                            32
Important notes to remember when collecting data:
      - Each set up must have a DIFFERENT total resistance.
      - Since voltage is not one of your variables you will not be measuring the voltage of anything!
         No need to use the voltmeter—you already know the voltage of the battery!
      - If you place your cursor over the resistor without clicking and leave it there for a few
         seconds, the resistance of that resistor will show up. Resistance is measured in ohms (  )
      - Place the ammeter on the closed circuit to get the current of the circuit. Current is measured
         in amps (A)
      - You are only doing this on one branch
      - Write the total resistance for each set up in the total resistance column of your table, this way
         you can make sure that you don‘t repeat any total amounts

          Draw a circuit diagram for your 1st set up.




          Draw a circuit diagram for your 2nd set up.




          Draw a circuit diagram for your 3rd set up.




          Draw a circuit diagram for your 4th set up.




          Draw a circuit diagram for your 5th set up.




          Draw a circuit diagram for your 6th set up.




          Draw a circuit diagram for your 7th set up.




                                                                                                       33
       Draw a circuit diagram for your 8th set up.




   Draw a circuit diagram for your 9th set up.




   Draw a circuit diagram for your 10th set up.




   Draw a circuit diagram for your 11th set up.




   Draw a circuit diagram for your 12th set up.




   Draw a circuit diagram for your 13th set up.




   Draw a circuit diagram for your 14th set up.




   Draw a circuit diagram for your 15th set up.




                                                      34
The Data Collection:
   Create a data table to record the sum of the resistance for each circuit and the total current for each
   circuit you made. ALSO, IN YOUR TABLE HAVE A PLACE TO RECORD THE VOLTAGE OF
   THE BATTERY WHILE HOOKED UP IN EACH OF YOUR CIRCUITS EVEN THOUGH IT IS
   NOT ONE OF THE VARIABLES.
   Keep your eye out for any patterns you might notice emerging…


        VOLTAGE                   TOTAL CURRENT                 TOTAL RESISTANCE




                                                                                                        35
The Graph:
Graph your data on graph paper.  Look back at your variables to determine which goes on the X-axis
_____________and which goes on the Y-axis_________________. Don‘t forget TALUNK!
Draw the curve of best fit


          Checkpoint: Call a teacher over and we will discuss your graph with you.


                  The Analysis:
                  Summarize your results by answering the following questions in complete
                  sentences.

   1.    What is the relationship between the total current and the total amount of resistance that is in the
        series circuit? Justify your answer by relating it to trends on your graph.


   2. As the total resistance gets smaller and smaller and smaller, what happens to the total current


   3. As the total resistance gets bigger and bigger and bigger, what happens to the total current?


   4. Describe resistance.


   5. Describe current.


   6. Describe voltage.



          Class discussion about the analysis questions!


   The Formula:
      Voltage, current and resistance in a series circuit are mathematically related. In other words, if
      you know the total resistance and the voltage of the battery, you can solve for current using
      algebra. Write a formula that will allow you to calculate the current if you know the total
      resistance and voltage of the battery in a series circuit.




                                                                                                           36
37
38
                 LAB: Lemon Battery Challenge
             When life gives you lemons… make a battery!


Your Goal
    To make a LED light using a lemon battery.

Materials Available
     -lemons                    -galvanized nails (zinc coating over steel nails)
     -wires + alligator clips   -copper wire
     -plastic knife             -LED (light emitting diode)
     -multimeter

Information on Batteries
Remember that the movement of electrons through a circuit is an electric current. The terminals of a
battery are the points where electrons flow in or out. Electrons will flow from the negative (-) terminal
of a battery (called the anode) towards the positive (+) terminal of a battery (called the cathode).

Electron flow can be produced by some chemical reactions. For example, modern batteries consist of
two different metals (called electrodes) suspended in an acidic solution (called an electrolyte) to power
their reaction. Some metals give electrons away while other metals accept extra electrons. In 1800
Alessandro Volta made the first battery by layering copper and zinc in a jar of salt water. The zinc
readily gives up electrons and acts as the (-) terminal, while the copper draws electrons through the
circuit to the (+) terminal. The voltage of the battery comes from the relative difference in the ability of
the two metals to give up electrons. The electric current generated by the battery depends on the quantity
of electrons released by the chemical reaction.

        Sketch a diagram of a typical battery, based on the information above. Label the battery with the
       following terms: (+) terminal, (-) terminal, cathode, anode, metals (electrodes), acidic solution
       (electrolyte). Then show the direction of the flow of electrons on your diagram with an arrow.




                                                                                                 teacher initials

        Now sketch how you would make a lemon battery based on your diagram above and the materials
       available. Label your lemon battery sketch with the following terms: (+) terminal, (-) terminal, cathode,
       anode, copper wire, zinc-plated nail, citric acid in lemon (electrolyte). Then show the direction of the
       flow of electrons with an arrow.




                                                                                                                39
                                                                                            teacher initials
Constructing Your Circuit
Consider the following as you attempt to make a LED light using a lemon battery…
      How are materials connected in a circuit?
      Copper wire has surface area; to increase that surface area (or contact surface for the chemical
       reaction to occur) copper wire can be wrapped around your finger to produce a tightly-knit coil.
       How could you make this a part of the battery?
      Batteries can be connected in series and their voltages added together. The (+) terminal of one
       battery would be connected to the (-) terminal of another.
      The LEDs are 1.8 V; the slightly longer wire coming from the LED is the (+) terminal. The LED
       may not be very bright, so be observant when testing the circuit!


   1. Try lighting the LED with a single lemon battery.

             Does the LED light? ____________
             What is the voltage measured from a single lemon battery? _____________________

   2. How many lemon batteries are needed to light up the LED? _________________

   3. Record the voltage of each lemon battery in the circuit, as well as the total voltage of the circuit
      that allowed the LED to light.




                                                                  total voltage? ____________________

   4. How much current (in mA) is flowing through the circuit when the LED is lit? ____________


   5. Draw a circuit diagram (using the correct symbols!) for the set up that resulted in the LED being
      lit. Show the direction of the flow of electrons with an arrow.




   6. Will adding more and more lemon batteries to the circuit make the LED light brighter? If you are
      unsure, try it with your neighbors! Why or why not? (Think Ohm’s Law!)




                                                                                                           40
41
42
It‘s time to check out a circuit when it is hooked up in parallel. First, let‘s talk about what it means to be
a parallel circuit.
        Notes:


The Problem:
      To investigate the relationship between current, voltage and resistance in parallel circuits.

The Material:
     You will have 2 batteries, several wires, a multi meter, a switch and 3 2.5-volt bulbs.


The Procedure
Diagram 1: Draw a series circuit with 2; 1.5v batteries with 1 bulb and a switch




Diagram 2: Draw a series circuit with 2; 1.5v batteries and 3 bulbs and a switch




Diagram 3: Draw a parallel circuit with 2; 1.5 v batteries and 3 bulb over 2 branches and a switch




Diagram 4: Draw a parallel circuit with 2 1.5v batteries and 3 bulbs over 3 branches and a switch




       Checkpoint: I will be checking out your circuit diagrams in your plans.
Data Collection: Record all data in appropriate places on your circuit diagrams. –be sure to use the
proper settings on your multimeter—also, look ahead to the analysis questions as some of them you
can answer as you are performing the lab




                                                                                                           43
      1. Record the voltage across the bulbs for each setup
      2. Measure the current in the circuit by touching the leads of the multimeter to the terminals of
         the switch (remember, the switch needs to be open such that the multimeter completes the
         circuit)

Analysis Questions part 1: Don’t put your setup away just yet, you may need to collect more
data to answer some analysis questions.

      1. How does the voltage of a branch compare to the voltage of the battery?


      2. Compare the brightness of the 4 setups



      3. Compare the TOTAL CURRENT in the different setups




      4. Find a relationship between the brightness and current for your 4 setups



      5. Remove 1 bulb from setup 4:
            a. What happens to the other 2 bulbs



             b. What is the current and voltage of the 2 remaining lit branches?




      6. How much voltage should each of two identical bulbs expect to have compared to the
      battery‘s voltage, if the bulbs are hooked up in parallel?



      7. What is it about the path of the electrons that causes this to happen?


      8. Think back to your series lab. When hooked up in series, how much voltage should each of
      two identical bulbs have compared to the battery‘s voltage?




                                                                                                      44
       9. What is it about the path of the electrons that causes this to happen?



Analysis questions part 2

   1. What happens to the total current when more resistance is added in SERIES?



   2. What happens to the total current if a new branch is added?



   3. What happens to the total current when resistance is added to an existing branch in parallel?



   4. What is the relationship between resistance and current in a closed circuit?



   5. Based on your previous answers, does the resistance of a circuit increase or decrease when
      resistors are added in new parallel branches?



   6. THE MILLION DOLLAR QUESTION…Why do the current and resistance act this way when
      adding resistors in new branches (parallel)? What is it about the set up of a parallel circuit that
      makes this happen?




       Once you and your team are finished, please go back to you seat.

TIME TO MAKE SURE WE GET THE BIG IDEAS!!!
Using the information you learned about parallel circuits from this lab, fill in a voltage for every
question mark. Assume identical resistors and identical bulbs. Pay attention to the battery direction
in the diagram B!!!




                                                                                                        45
                            A                                                        B

                        ?
                                                                                          ?
2volts                                                  10v
                                                                                                              ?
                    ?                       ?
                                                                                         ?
                                                          20v




         1. Now, solve for current given that the resistance for the two resistors on the first branch in A are
         2ohms, and the resistance for the resistor on the second branch in diagram A is 3 ohms. Remember
         there are three steps to finding the TOTAL CURRENT in this set up!




         2. Now, solve for the current given that the resistance for the two bulbs in the first branch of diagram B
         are 4ohms and the resistance for the bulb on the second branch in diagram B is 4 ohms. Remember
         there are three steps to finding the TOTAL CURRENT in this set up!




                                                                                                                  46
47
48
                              REVIEW: Creating Candy Circuits!
Materials:
                Batteries         Voltage                            Resistors             Resistance
               Milky Way            3V                           Sweet Tart - green           1
                Snickers            6V                           Sweet Tart - yellow          2
                 Twix              12 V                           Sweet Tart - blue           4
              3 Musketeers         24 V                          Sweet Tart - orange         12 

                                                                + Twizzlers:   zero resistance wires
Instructions:
    First construct the circuit AS A TEAM using the candy provided.
      Then draw and label the circuit (using the appropriate circuit symbols!) in the space provided.
      When your team has reached a STOP, ask your instructor to check your team‘s circuit diagrams.
       One member of the team will be chosen at random to explain a circuit. Please be sure
       *everyone* feels prepared before checking in!



1. Construct a single resistor circuit with a current of 1 A.




2. Construct a double resistor circuit with a resistance of 6 .




3. Construct a circuit with a current of 2A




                                                                                Have your teacher
                                                                                check your circuit
                                                                                   diagrams!




                                                                                                         49
4. Using 3 resistors, construct a parallel circuit that will have the largest possible resistance.




5. Using 3 resistors, construct a series circuit that will have the smallest possible resistance.




6. Using 2 resistors and only 1 battery, construct a circuit that will have the largest current.




7. Using 2 resistors and only 1 battery, construct a circuit that will have the smallest current.




8. Construct a circuit that will have a current of exactly 8 .




                                                                                     Have your teacher
                                                                                     check your circuit
                                                                                        diagrams!
                                LAB: Household Energy Usage




                                                                                                          50
Introduction
Niagara Falls is one of the most awe-inspiring natural features in the world. In 1759,
Daniel Joncairs became the first to harness the power of the mighty falls. He dug a
ditch that diverted a small amount of water from the river above the falls and used
the flowing water to turn a waterwheel that, in turn, powered a small sawmill.

In 1957, nearly 200 years later, construction began on a considerably larger project
designed to harness the power of the Niagara River. The Robert Moses Power
Generating Station diverts 600,000 gallons of water per second from the Niagara
River 2.5 miles upstream from the falls. The water returns to the river four miles
later after passing through turbines and generating 2.4 million kilowatts of power!

So what do we, as humans, do with all of this electrical power? Consider all of the
things you wouldn‘t have been able to do today without the power of electricity! This investigation will
allow you to explore the energy used by many household appliances, such as TVs, hair dryers, lights,
and computers. Make estimates for how long each item is used on a daily basis to get an estimate for the
total power consumed during a day, a week, a month, and a year, and how that relates to consumer costs.

Starting the Gizmo
     8.    Go to the website: http://www.explorelearning.com
     9.    At the top of the page, click ―LOGIN‖ and enter (case sensitive!)
                   username:
                   password:
    10.    Begin the correct gizmo by selecting ―Household Energy Usage.‖



Part A: Calculating the Rate of Energy Consumption
In this activity, you will examine the characteristics of several electrical household appliances and
calculate the rate at which these appliances consume energy. You will then figure out the monetary cost
of operating these devices.

In the GizmoTM, be sure that the BEDROOM tab and the POWER tab are selected, and then click
Reset (     ) all appliances. Click on the reading lamp on the nightstand next to the bed. The POWER
tab gives information about the lamp, including what kind of bulb it has (incandescent, which is the
"typical" light bulb you're probably used to).

   1. What is the maximum voltage at which the reading light operates? ___________________


   2. What amount of current (in A) is drawn through the light? ___________________


   3. The rate at which energy is ―used‖ by an electrical device is referred to as electrical power.




                                                                                                       51
           1. Is energy really ―used up‖ by any electrical device? Explain what really happens using
              your knowledge of physics.




           2. What equation is used to calculate the power ―used‖ by an electrical device?



           3. Electrical power is measured in a unit called watts (W). As a result, the electrical power
              of a device is also referred to as wattage. Examine the calculation of the wattage of the
              incandescent light shown in the POWER tab. What is the wattage of this lamp? Show
              your work!



           4. Electrical power is also expressed in kilowatts (kW). Explain why the two values shown
              for wattage (60 W and 0.06 kW) are the same.



With the incandescent light still selected, click the USAGE tab. Suppose that one night you read in bed
for two hours with the lamp on. Use the sliders to set hours to 2 and minutes to 0.

   4. How could you calculate energy consumption of one device for a given amount of time?



   5. What is the energy consumption of the incandescent lamp when it is turned on for two hours?
      Show your work; remember wattage must be in kW!



   6. What unit is used to express energy consumption over time? ___________________________

   7. Click the COST tab. Set the Cost of Electricity to 10¢/kWh (cents per kilowatt hour). Select 1
      day. What is the cost of running the incandescent light for two hours a day at this price for
      electricity? (The value will be rounded to the nearest cent.) Show your work!




   8. Select 1 year. What is the cost of running this lamp for two hours each day for an entire year?
      Show your work!




                                                                                                        52
Part B: Comparing the Consumption of Electrical Appliances
In this activity, you will examine a variety of electrical appliances and compare their rates of energy
consumption.

   9. Click Reset all appliances. You will now compare the rates of energy consumption of three
      different light sources. Be sure the BEDROOM tab is selected. Turn on the incandescent light
      on the nightstand again.
          1. Click the POWER tab. Re-record the following: what is the current drawn by this
              device? what is the wattage (power) of the device?

               I = ________________        P = ______________

           2. Select the pole light at the foot of the bed. This is a halogen lamp. How much current
              does this lamp draw? What is its wattage (power)? How does this compare to the
              incandescent lamp?

               I = ________________        P = ______________

           3. Go to the KITCHEN and turn on the fluorescent light hanging from the ceiling. How
              much current does this light draw? What is its wattage (power)? How does this compare
              to the other two types of lamps?

               I = ________________        P = ______________

           4. Assuming that each of the three lamps produces a comparable amount of light, which of
              the three is the most economical? Which is the least economical? Justify your response.




   10. Now you will compare the energy consumption of all the electrical devices in these four rooms.
         1. Click the POWER tab. Select BEDROOM. Click on each of the electrical devices.
             Which device requires the most power (wattage) to operate?



           2. Select KITCHEN. Which device in the kitchen requires the most power (wattage) to
              operate? What is the similarity between the most energy-hungry device in the bedroom
              and those in the kitchen?




                                                                                                          53
              3. Select LAUNDRY. Examine the four electrical devices here. Which consumes energy at
                 the lowest rate? How does this device differ in its function from the other three devices?



              4. Perform the same test in the LIVING room. Examine the six electrical devices here.
                 Which consumes energy at the lowest rate? How does this device differ in its function
                 from the other five devices?



Part C: Considering the Actual Cost of Various Electrical Devices
In this activity, you will consider more thoroughly how much it costs to run various
electrical devices. According to the Department of Energy, the average retail price of
electricity in Illinois as of December 2008 was 10.89¢/kWh. Set the Cost of Electricity
to 11¢/kWh for this activity.
    11. For each question below, please try the problem first on your own, and then use the various tabs
        on the Gizmo to check your answer!
            1. Go to the BEDROOM. Click the POWER tab.
                   -What is the wattage of the hair dryer? _________ kW
                   -How long do you think one might run a hair dryer in a single day? _________ hr
                   -What is the energy consumption of the hair dryer if its runs this long? _________ kWh
 Remember to       -How much would it cost to use the hair dryer for that day? _____________
convert cents to
   dollars!        -How much would it cost to use the hair dryer daily for one month? ___________

                   Actual Answer: ________________

              2. Go to the LIVING ROOM. Click the POWER tab.
                   -What is the wattage of the TV? _________ kW
                   -On average, how many hours per day do you watch TV? _________ hr
                   -What is the energy consumption of the TV if its runs this long? ___________ kWh
 Remember to
convert cents to   -On average, how much would it cost to watch TV for that day? ____________
   dollars!
                   -On average, how much would it cost to watch TV for one month? ___________

                   Actual Answer: ________________

    12. Click Reset all appliances and select the USAGE tab. Starting from the time that you wake in the
        morning, click on each electrical device that you would use during a 24-hour period and enter the
        time that it would be running during that time. Do this for every room in the house. You can
        select CONSUMPTION at any time to see a list of the devices that you have activated and the
        amount of energy that each would consume in a single day.




                                                                                                         54
1. Under the CONSUMPTION tab, what is your total daily energy consumption?
                                                          ________________ kWh

2. Based on a cost of 11¢/kWh, what would be your electric bill for one month? Check it out
   under the COST tab!
                                                             _________________
3. Does this surprise you? Share your reaction.



4. In the city of Chicago, I pay 11.3¢/kWh according to my ComEd statement. Last month,
   my electrical usage according to my meter was 270 kWh. What was my electric bill last
   month (minus any standard fees and taxes)? Show your work; remember to convert cents
   to dollars!




                                                                                        55
                       NOTES: Current, Resistance, & Voltage
                            Sections 13.2 and 13.3 (pages 302-311)

REVIEW! Electrostatics
   Charge on objects is ―static‖ – meaning it is NOT __________________________________.
   Objects can have either a ______________ or _______________ charge.
   A _______________ is created between the charges (aka Coulomb‘s Law!).
   There are _____ ways to create charge on an object: ___________________________________

                                                         ___________________________________

                                                          ___________________________________

What is electric current?
   Current is the ______________________ of electric charge, or the flow of charge.
   Current ―flows‖ when _________________________________________ move!
   Current (I) is measured in _________________________________________________.


Which way does current flow?
   __________________________________ developed the idea of electric
      current; the first to use the terms ___________________ and
      ____________________ to describe charge.

   We define current as flowing from _______ to _______, even though the
      direction in which electrons move in a circuit is from ______ to _______.


Why does current flow?
   Electric current only flows when there is a ________________________________________
    between two points in a circuit.
   Just as _____________ flows downhill from _________ gravitational PE to ________
    gravitational PE…
   Current flows from __________ electrical PE to __________ electrical PE.


What is voltage?
   Voltage measures the ______________________________________________________
    between two points in a circuit.
            (Think of this like height measuring the difference in gravitational PE!)
     Voltage (or electrical PE) is measured in ____________________________.




                                                                                            56
     A                                                                    difference in voltage
      is                                                                   required for current
      to flow;                                                             means there is
                                                                           _____________ to
      do
                                                                           _____________!




Creating a difference in voltage
   A battery uses ________________________________ to create a voltage difference between its
    2 terminals.




What is resistance?
   Resistance is a measure of how strongly a wire or other object
    _________________________ flowing through it.
   Resistance (R) is measured in _____________________________.
   Think of the relationship between resistance and current like water




                                                                                             57
     flowing from a bottle - the relationship is ______________________.




                                                                           Materials current
                                                                           can flow through




   _________________________________ :
          -current passes easily through these materials!
          -electrons flow freely
          -have very ___________ resistance
          -Examples?


   _________________________________ :
            -have ___________ resistance
            -Example?


Materials current CANNOT flow through
   _________________________________ :
          -current does NOT easily pass through these materials; block the flow of current
          -electrons DO NOT flow freely
          -have very ___________ resistance
          -Examples?


Conductors and Insulators




                                                                                               58
Resistance of common objects
   The resistance of objects _________________. Electrical devices are designed with a
     _____________________ that causes the right amount of _______________ to flow when the
     device is connected to the proper __________________.
   Dry skin? Resistance = __________________________
   Wet skin? ____________________________________! Therefore, the same voltage will cause
     more current to pass through your body!




                                                                                              59
Freshman Physics           Name:______________________________________ Per:____
ACT: AC/DC Webquest                                   Due Date:_________________

INTRO: The great debate between which type of electricity was better—Alternating current
(AC) or Direct current (DC) was a hot topic for many years in the late 1800s. Through this web
quest you will gain more insight on the principles behind each type of electricity by going
―inside‖ the wire that carries the electrical current, the battery that generates the DC, the
generator which produces AC current and the light bulb which illuminates as a result of the
electrical currents passing through it.

WEBSITE: http://www.pbs.org/wgbh/amex/edison/sfeature/acdc.html



                                       1. Click on the button to allow for Direct Current.
                                              a. Draw where the switch needs to be positioned
                                   for DC.

                                             b. Draw the flow of electrons in DC mode.


                                             c. Where is the ―power‖ for DC coming from?




                                             d. Does the current change? How can you tell?



   2. Click on the button to allow for Alternating Current.
          a. Draw where the switch needs to be
             positioned for AC.

          b. Draw the flow of electrons in AC mode.


          c. Where is the ―power‖ for AC coming from?



          d. Does the current change? How can you
             tell?




                                                                                            60
Click on ―Go Inside the WIRE‖
  3. Label the parts of the copper atom depicted below:




   4. Electricity is _____________________________________________________.

   5. Look at your labeled picture of the copper atom again.
         a. How many electrons does it have in its outer (valence) shell?



         b. What does this mean about the strength of its ―attachment‖ to the atom?


   6. Not all materials make good conductors of electricity.
         a. Copper is a GOOD / POOR conductor of electricity because the electrons are
              able to move FREELY / NOT SO FREELY.

         b. Carbon is a GOOD / POOR conductor of electricity because the electrons are
            able to move FREELY / NOT SO FREELY.

   7. Current describes ______________________________________________________

      _____________________________________________________________________

      _____________________________________________________________________

         a. High current means ___________ electrons are in motion.

   8. Voltage describes ______________________________________________________

         a. High voltage means ___________ of energy.

 Click on ―Go Inside the BATTERY‖
   9. Draw a sketch of the components that make up a battery (like a Duracell ®)




                                                                                         61
  10. Where do the electrons come from in a battery?




  11. In our light bulb circuit, electrons want to go from the _______________ terminal of the

     battery to the _____________ terminal of the battery. What allows them to do this?

     (i.e.-where do they travel?) ______________________________.

  12. Batteries produce ______________ current because __________________________

     _____________________________________________________________________

 Click on ―Go Inside the AC GENERATOR‖
  13. What is the purpose of a generator?




  14. The wire inside the generator (usually in a coil) is called the ____________________.

  15. Look at the animation of the AC generator.
         a. What do you notice about the direction of the current?


        b. What causes this?



  16. This generator produces __________________ current because _______________

     ____________________________________________________________________.

  17. A transformer can take _________________ current and turn it into

     __________________ current and vice versa. Why is this beneficial?




                                                                                              62
 Click on ―Go Inside the LIGHT BULB‖
   18. Label the resistor part of the light bulb diagram.

   19. Label where the electrons flow the most easily on the   light
       bulb diagram.

   20. The work done overcoming the resistance of the light    bulb

      causes __________________________________

      ____________________________________________.




                                                                 63
64
65
                              LAB: Electrostatics

Introduction
  Have you ever shuffled your feet across the carpet and then reached for a door
  knob, only to be zapped by a lightning-like spark? Or have you rubbed a balloon
  on your head and made your hair stand straight up? Most everyone has been
  ―shocked‖ by the ability of electrons to transfer from one object to another, particularly
  on dry winter days!
  In this lab you will investigate the principles of electrostatics, or ―static electricity.‖ Static electricity
  is caused by an imbalance of either positive or negative charge on an object, allowing for the transfer
  of electrons. Knowing the structure of the atom is important to understanding static electricity. The
  atoms of a solid object are held tightly in place. Their nuclei are not free to move about within the
  solid. Since the nuclei contain the protons in an atom, the amount of positive charge in a solid
  remains fairly constant.
  Therefore it is the electrons outside of the nucleus that are the key to understanding static electricity
  and charges on objects. With the addition or removal of energy, the outer electrons can be removed
  from or added to atoms. An atom missing electrons has an overall positive charge, and any matter
  made of these electron-deficient atoms will be positively charged. Conversely, if an atom has excess
  electrons, it will have a negative charge. Materials made of these atoms will be negatively charged.
  Substances‘ atomic makeup causes them to vary in their ability to give up or take on electrons. An
  atom holds onto its negative electrons by the electromagnetic force with its positive nucleus. Some
  atoms exert stronger forces than others on their electrons.

Procedure
Part A: Observing electric charge
   11.    Cut out some small 3 – 4 cm ―leaves‖ of aluminum foil (see diagram below) and use a nail to
          punch a small hole near the top of each leaf.




   12.    Suspend one leaf from a thread that you will hold up in one hand.
   13.    Rub an inflated balloon against your hair and move it towards the foil leaf. What does the
          leaf do?




                                                                                                             66
   14.   Touch the rubbed part of the balloon to something metal (like the faucet), and then bring the
         balloon close to the leaf again. (You may have to do this a few times in winter if it is really
         dry!) What does the leaf do this time?
   15.   Repeat steps 3 and 4 by bringing other objects near the leaf after being rubbed with various
         materials. The key to this step is to make sure the person holding the foil leaf touches the leaf
         to the metal faucet after each trial. Another person needs to vigorously rub the glass, plastic,
         or rubber rod with various materials; then slowly bring the rod up to the foil leaf. Observe
         what happens to the foil leaf in each situation and record your observations in the data table.
                                              Note: If the glass rod rolls off the table, it WILL break!
                                              Please keep it in the bag or materials tray at all times!
Part A - Data Table     (put a * next to the one or two that moved the most)

            Object               Rubbed with…                        Observation of metal leaf
                                                              (movement (some or a lot)? no movement?)

           glass rod                  flannel

                                       silk

                                        fur

          plastic rod                 flannel

                                       silk

                                        fur

          rubber rod                  flannel

                                       silk

                                        fur

   16.   When you have completed your observations, compare your data with another group. For any
         results that differ, re-test that set of materials.

   17.   In comparing your Part A Data Table with another group in class, did you have the exact
         same results for each trial? If not, list what variable(s) might have caused your results to
         differ.




               Call your teacher over before moving on…




                                                                                                           67
Part B: Making an electroscope
    18.    Make the electroscope (see diagram) by hanging
           two foil leaves on the copper wire, which is
           balanced over the edge of a 400 mL beaker.

    19.    Rub an inflated balloon against your hair and
           move it towards the end of the wire sticking out
           of the beaker. What do you observe about the
           foil leaves?



    20.    Then gently touch the balloon to the wire and move it away. What do you observe about the
           foil leaves?
    21.    Now touch the end of the wire with your finger or a metal object. What do you observe about
           the foil leaves?


    22.    ―Charge‖ the electroscope again by touching it with a balloon that has been rubbed against
           your hair. Then touch the rubbed side of the balloon to something metal and bring it close to
           the electroscope again. What happens?


    23.    Bring the uncharged plastic rod near the wire. What do you observe about the foil leaves?




    24.    Rub the plastic rod with a material that will charge it and bring it near the wire again. What
           do you observe about the foil leaves?


    25.    Be sure before leaving the lab that you have a good record of your observations. If you are
           still unsure of anything, test it again! You will need to use these observations to answer the
           analysis questions. Neatly return all the materials to where you found them and check out
           with your instructor.

Lab Analysis
Please answer in complete sentences, and in your OWN WORDS!

Part A
 1. Explain the reaction of the foil leaf to the rubbed balloon in terms of positive and negative charge.




                                                                                                       68
 2. Explain why touching the rubbed balloon to a metal object changed its effect on the foil leaf.

Part B
 3. What causes the foil leaves of the electroscope to move apart? Why do the foil leaves stay apart,
     even after the balloon is removed from the wire?


 4. Explain what happens when you touch the wire with your hand or a metal object.




 5. Why does the plastic rod cause the leaves to move only after it has been rubbed with one of the
    materials?



In Conclusion (Hint: re-read the introduction!)
  6. What causes static electricity?




 7. There are three ways to charge an object. Based on what you observed today, list the three ways
    you were able to ―charge‖ the rods and/or foil leaves.




 8. Rubbing your shoes along the carpet provides energy to transfer electrons from the carpet
    to your body.
      a) As a result, you become __________________________ charged.

       b) If you were to reach for a door knob, the excess _______________________ are suddenly
           released from your body, causing a visible _____________; you feel a _______________.


 9. Atoms in rubber are more reluctant to give up electrons than atoms in fur. After rubbing the rubber
    rod with the fur material…

       a) which object has an excess of electrons (negatively charged)? _______________________

       b) which object gave up electrons (positively charged)? ______________________________




                                                                                                        69
      Justify your answer:
Freshman Physics           Name:_____________________________________ Per:____
H.O.-Types of Electricity                             Due Date:_______________

Common types of electricity are static electricity, direct current (DC) electricity and alternating
current (AC) electricity.

STATIC ELECTRICITY
        Static electricity is the collection of free electrons on the surface of a material, giving it a
negative (−) charge. Atoms on the surface of another material that have lost one or more of
their electrons are called positive (+) ions, cations.
        Static electricity is the accumulation of electrical charges on the surface of a material,
usually an insulator or non-conductor of electricity. It is called ―static‖ because there is no
current flowing, as there is in alternating current (AC) or direct current (DC) electricity.
        Typically, two materials are involved in static electricity, with one having an excess of
electrons or negative (−) charges on its surface and the other material having an excess of
positive (+) electrical charges. Atoms near the surface of a material that have lost one or more
electrons will have a positive (+) electrical charge.




                             Negative (-) charges collect on PCV pipe surface

       If one of the materials is an electrical conductor that is grounded, its charges will drain
off immediately, leaving the other material still charged.
       .
DIRECT CURRENT ELECTRICITY




        If the opposite charges are constant, such as with the terminals in a battery, the current
is called direct current or DC electricity, because it is going one direction. DC can be created
by a battery or DC generator. DC is used in many devices that do not require high voltages for
their operation, such that batteries are used for power.
        The electricity moving through a wire or other conductor consists of its voltage (V),
current (I) and resistance (R). Voltage is potential energy, current is the amount of electrons
flowing through the wire, and resistance is the friction force on the electron flow. These three
variables can be compared to water traveling in a hose. See the table below:

Water in a Hose                    DC In a Wire                         Electrical Units




                                                                                                      70
pressure              potential (V)                                Volts (V)
rate of flow          current (I)                                  Amperes, Amps (A)
friction              resistance (R)                               Ohms (Ω)
ALTERNATING CURRENT ELECTRICITY




        If the terminals constantly switch their polarity from (+) to (−) and back again, the
direction of the electrons alternates and is call alternating current or AC electricity.
Alternating current electricity is the type of electricity commonly used in homes and businesses
throughout the world. AC is different than the direct current (DC) electricity that comes from a
battery and flows in one direction through the wire. AC electricity alternates directions. The
back-and-forth motion occurs between 50 and 60 times per second, depending on the
electrical system of the country.
        AC electricity is created by an AC electric generator, which determines the frequency.
What is special about AC electricity is that the voltage can be readily changed, thus making it
more suitable for long-distance transmission than DC electricity. But also, AC can employ
capacitors and inductors in electronic circuitry, allowing for a wide range of applications.

THE GREAT AC/DC DEBATE
        In 1887 direct current (DC) was king. At that time there were 121 Edison power stations
scattered across the United States delivering DC electricity to its customers. But DC had a
great limitation -- namely, that power plants could only send DC electricity about a mile before
the electricity began to lose power. Since the electrical flow was only in one direction, a very
high voltage had to be used to allow it to travel large distances. When it reached the
consumer’s house, however, most of the appliances did not need such a high voltage.
―Turning down‖ the voltage was not easy or practical with DC electricity. So when George
Westinghouse introduced his system based on high-voltage alternating current (AC), which
could carry electricity hundreds of miles with little loss of power, people naturally took notice. A
"battle of the currents" ensued. In the end, Westinghouse's AC prevailed. Since a light bulb
only requires a moving current to operate, it doesn’t care which direction the electrons are
traveling. This alternating current allows electrical companies to adjust the voltage from its
travel through the wires to the consumer’s house more efficiently and effectively.




                                                                                                  71
                     How Christmas lights work


Go to www.howstuffworks.com
In the search window, type in Christmas lights
Click on the link for Christmas lights in the how stuff works website or type in the link:
http://home.howstuffworks.com/christmas-lights.htm

   1. Read the first page and click on the next button (continue to do this as you work through the rest
      of this guide)

   2. Why were the lights used 30 or 40 years ago dangerous?
      ______________________________________________________________________________
      ______________________________________________________________________________
      __________________________________________

   3. What is the one advantage of these bulbs?
      ______________________________________________________________________________
      ______________________________________________________

   4. What type of circuit were these in? __________________

   5. In the 70‘s, the mini lights came about. Briefly explain how these work?
      ______________________________________________________________________________
      ______________________________________________________________________________
      __________________________________________

   6. What happens in these strands when one bulb goes out?
      ______________________________________________________________________________
      ______________________________________________________________________________
      _________________________________________

   7. In today‘s lights, they have corrected this problem, what did they do? Briefly explain and draw a
      picture.
   _________________________________________________________________________________
   _________________________________________________________________________________
   _____________________________________________




                                                                                                      72
8. Explain how the 100 and 150 bulbs work.
   ______________________________________________________________________________
   ______________________________________________________________________________
   __________________________________________

9. What is happening to the overall current with the strands of bulbs like in number 8?
   ____________________________________


10. Explain why you might blow a fuse in your house if you have the lights on, a blow dryer going
    and the bathroom heater all at the same time.
    ______________________________________________________________________________
    ______________________________________________________________________________
    __________________________________________

11. Explain how blinking lights work.
    ______________________________________________________________________________
    ______________________________________________________________________________
    ______________________________________________________________________________
    ______________________________________________________________________________
    ______________________________________________________________________________
    ______




                                                                                              73
                      NOTES: Current, Resistance, & Voltage
                           Sections 13.2 and 13.3 (pages 302-311)

REVIEW! Electrostatics
   Charge on objects is ―static‖ – meaning it is NOT __________________________________.
   Objects can have either a ______________ or _______________ charge.
   A _______________ is created between the charges (aka Coulomb‘s Law!).
   There are _____ ways to create charge on an object: ___________________________________

                                                        ___________________________________

                                                         ___________________________________

What is electric current?
   Current is the ______________________ of electric charge, or the flow of charge.
   Current ―flows‖ when _________________________________________ move!
   Current (I) is measured in _________________________________________________.


Which way does current flow?
   __________________________________ developed the idea of electric
     current; the first to use the terms ___________________ and
     ____________________ to describe charge.

   We define current as flowing from _______ to _______, even though the
     direction in which electrons move in a circuit is from ______ to _______.


Why does current flow?
   Electric current only flows when there is a ________________________________________
    between two points in a circuit.
   Just as _____________ flows downhill from _________ gravitational PE to ________
    gravitational PE…
   Current flows from __________ electrical PE to __________ electrical PE.




                                                                                            74
What is voltage?
   Voltage measures the ______________________________________________________
    between two points in a circuit.
            (Think of this like height measuring the difference in gravitational PE!)
     Voltage (or electrical PE) is measured in ____________________________.
     A                                                                     difference in voltage
      is                                                                    required for current
      to flow;                                                              means there is
                                                                            _____________ to
      do
                                                                            _____________!




Creating a difference in voltage
   A battery uses ________________________________ to create a voltage difference between its
    2 terminals.




What is resistance?




                                                                                              75
   Resistance is a measure of how strongly a wire or other object _________________________
    flowing through it.
   Resistance (R) is measured in _____________________________.
   Think of the relationship between resistance and current like water
     flowing from a bottle - the relationship is ______________________.




                                                                           Materials current
                                                                           can flow through




   _________________________________ :
          -current passes easily through these materials!
          -electrons flow freely
          -have very ___________ resistance
          -Examples?


   _________________________________ :
             -have ___________ resistance
             -Example?


Materials current CANNOT flow through
   _________________________________ :
          -current does NOT easily pass through these materials; block the flow of current
          -electrons DO NOT flow freely
          -have very ___________ resistance
          -Examples?


Conductors and Insulators




                                                                                               76
Resistance of common objects
     The resistance of objects _________________. Electrical devices are designed with a
         _____________________ that causes the right amount of _______________ to flow when the
         device is connected to the proper __________________.
     Dry skin? Resistance = __________________________
     Wet skin? ____________________________________! Therefore, the same voltage will cause
         more current to pass through your body!

Ohms Law
Formula to solve for Current:

Formula to solve for Voltage:

Formula to solve for Resistance:



                                   Chapter 14 Parallel circuits

                                             Pg 317-333




• The voltage across a given branch is _________ to the voltage across the other branches
• There are two big advantages to parallel circuits over series circuits:
    1.

    2.


•   A good analogy to explain how parallel branches behave is like that of a ___________




                                                                                                  77
This is because______________________________________________________________
___________________________________________________________________________

•   Adding branches ______________ the total current
•   Adding branches ______________ the total resistance
•   Adding branches ______________ the voltage
• To find the total current in a parallel circuit, you _______________________________
___________________________________________________________________________
• To find the total resistance in a parallel circuit, you _____________________________
___________________________________________________________________________
• To find the total resistance in a parallel circuit, you _____________________________
__________________________________________________________________________

• A short circuit is defined as ___________________________________________________
_________________________________________________________________________


• Short circuits can be very dangerous because ___________________________________
________________________________________________________________________

Power
•Electrical power is measured in __________
• Electrical power is defined as
__________________________________________________
__________________________________________________
__________________________________________________
• A joule per second is also called a   ____________

• How is the electricity you pay for in your home calculated?
__________________________________________________
__________________________________________________

• Power is calculated using the formula:

                        AC DC
                        •The difference between alternating and direct current is
                        __________________________________________________
                        __________________________________________________




                                                                                          78
__________________________________________________
__________________________________________________

•   There are two ways to increase your power:
    1.

    2.




• What is the benefit to using larger wires?
______________________________________________________________________
______________________________________________________________________

• What are ground fault interrups and why are they necessary in your home?
__________________________________________
__________________________________________
__________________________________________
__________________________________________


          Chapter 15 Static Electricity
                                  pg 339-345
                      Most objects are naturally have a __________net charge

                      The tiny imbalance of either positive or negative charge is called
                      ___________________________

                      When you touch a door knob and feel an                          electrical
                      shock, what is it that you actually feel?
                      ____________________________________



                           Why will a charged balloon stick to a wall, but not to a doorknob or
                           metal surface? ____________________________________
                           _________________________________________________
                           _________________________________________________
                           _________________________________________________
                           _________________________________________________
                           _________________________________________________




                                                                                               79
• A nine volt battery supplies power to a cordless curling iron with a resistance of 18 ohms. How much
current is flowing through the curling iron?




• A CD player with a resistance of 40 ohms has a current of 0.1 amps flowing through it. Sketch the
circuit diagram and calculate how many volts supply the CD player?




• What is the resistance of a circuit that is powered by a 15 volt battery and has 8amps of current
moving through it?




                                                                                                      80
81
82
83
84
Freshman Physics                Name:___________________________________ Per:___
Vocab: Waves and Sound

INTRO: To develop an understanding of the vocabulary terms used to categorize properties of
waves, harmonic motion and sound. These terms correspond to Chapters 19-21 in your
textbooks. Drawing pictures may help you to understand some definitions!

NOMENCLATURE:

Amplitude:



Compression:



Constructive Interference:



Crest:



Decibels:



Destructive Interference:



Doppler Effect:



Frequency:



Harmonics:



Hertz:




                                                                                         85
Longitudinal:



Oscillation:



Period:



Phase:



Pitch:



Resonance:



Standing Wave:



Transverse:



Trough:



Vibration:



Wave:



Wavelength:




                 86
NOTES: WAVE ANATOMY




  1. Above is a wave made when a pendulum swings. When the pendulum swings back and forth, it
     means it is _________________ or _________________.

  2. How are waves made?
       a. Waves are made when_______________________________.

         b. Matter is the ______________________ that make up a substance.

         c. The _____________ is the substance in which the wave spreads out or
            ________________.

         d. Example: Sound waves spread out in air because air molecules oscillate.

  3. From what point to what point is….
        a. One complete back and forth of the pendulum: _______________

         b. One cycle: _______________

         c. One wave: _______________

         d. One wavelength: _______________

  4. How many waves are shown in the wave picture above? ____________________

  5. If one cycle (one wave) takes 2 seconds to pass a certain point. What is the wave‘s ….
         a. Period: ______________

         b. Frequency: ________________

         c. Period is the ________________ of frequency.


  6. Label the parts of the wave on the diagram below. These words should be added to your special
     vocab list!
        •Amplitude           •Wavelength          •Crest         •Equilibrium point          •Troug




                                                                                                87
                                 LAB: Harmonic Motion

Introduction
  Harmonic motion is a motion that repeats in cycles. Many important systems in nature and many
  useful inventions rely on harmonic motion. For example, the phases of the moon and the seasons
  are caused by the Earth‘s harmonic motion. In this investigation, you will explore harmonic
  motion using the simple swaying of a pendulum. The concepts you learn with the pendulum can be
  applied to other oscillators as well.
Part A: Observing the pendulum
   26.   If the pendulum has not been set up, use the picture to help
         you do so. Use three washers to start.
   27.   Start the pendulum swinging and observe for 30 seconds.
         a) Describe, in words, what one cycle of the pendulum looks
            like:


         b) Draw a sequence of sketches that illustrate one complete
            cycle using arrows to indicate the direction the pendulum                               is
            going at each point in the cycle.



   28.   The amplitude is the maximum amount the pendulum swings away from its resting
         position. The resting position is straight down. Using the pendulum apparatus, how will you
         measure amplitude?

Part B: Oscillators and Period
   29.   Use the stopwatch function on the timer to measure the time it takes the pendulum to
         complete 5 cycles (press the ―A‖ button to start and stop the watch). Release the pendulum
         with 30° amplitude. Record the time (in sec) for 5 complete cycles to occur in the data table
         below. Do three trials and average your results. Round all data to the hundredth.

               Trial 1            Trial 2             Trial 3            Average




   30.   Describe, in words, what the period of an oscillator is. Then calculate the period of the
         pendulum. Show your work!

                                                      T = ______________________
Part C: Measuring Period with a Photogate
   31.   Attach the photogate as shown in the diagram below. Try to keep the string length close to
         the length you used in Part B. The pendulum will break the light beam when it swings
         through the photogate.




   32.   Put the timer in period mode. With 30° amplitude release the pendulum, allowing it to
         complete 5 cycles as you did before. Observe the time measurements recorded by the
         photogate in seconds. Ignore the first reading or two; the readings become consistent after
         one cycle.
            a) What do you observe about the time readings as more cycles of the pendulum
                occur? What is this called and why does it happen? HINT: p. 418!




            b) What is the average time (to the hundredth) you get after each swing of the
               pendulum through the photogate?
                                               ___________________ seconds

            c) Is this time (in sec) the period of the pendulum? Hint! Look at your answer in Part
               B above! How is the time measured here related to the period of a pendulum?




Part D: What Variables Affect the Period of a Pendulum?
   33.   If you wanted to investigate the variables that affect the period of a pendulum, what could
         you change? List three variables you could change, and how you would change them:

            a)


            b)


            c)

   34.   You will now perform three short experiments to see how these three variables each affect
         the period of the pendulum. For each variable tested, write one sentence describing the

                                               89
          experiment and identify the independent and dependent variable for each. Remember to
          keep the other variables constant. Check in with your instructor when you finish Part D!
Effect of Amplitude on Period
       Description:


       Indep. Variable _____________________ Depend. Variable ________________

                Amplitude            Trial 1 Period        Trial 2 Period       Average Period
               (in degrees)             (in sec)              (in sec)              (in sec)




Effect of Mass of Pendulum on Period
       Description:



       Indep. Variable _____________________ Depend. Variable ________________

                   Mass              Trial 1 Period        Trial 2 Period       Average Period
              (# of washers)            (in sec)              (in sec)              (in sec)




Effect of Length of Pendulum on Period
       Description:



       Indep. Variable _____________________ Depend. Variable ________________

                 Length             Trial 1 Period         Trial 2 Period       Average Period
                 (in cm)               (in sec)               (in sec)              (in sec)




                                                 90
In conclusion…
Of the three variables you changed, only one affects the period of a pendulum. Which is it??
Lab Analysis
Parts A & B
   1. When graphing harmonic motion, amplitude (in degrees) is on the y-axis and time (in seconds)
      is on the x-axis. Look at the example below for graphing the harmonic motion of a pendulum:




              a) What is the pendulum‘s amplitude? ______________

              b) What is the time for one cycle, or period? ________________________

              c) How many cycles are shown on the graph? ____________


   2. In pencil, now you will graph your average time data from the 5 cycles in Part B. Label your
      axes first (including units!) and then title the graph as well. Label where the bold line intersects
      the y-axis as 0 degrees. Then plot the amplitude of 30° to the right and left every ½ period. If
       you are having trouble making a graph, read pages 419-420 of Ch 19.2 – Graphs of Harmonic Motion!




                                                   91
  a) Amplitude is the maximum distance of the pendulum from its rest position.
     What is the amplitude of the pendulum illustrated in this graph? _____________________

  b) One complete back and forth is called a cycle.
     How many cycles does your graph show? ___________________________

  c) Period is the time needed to complete one cycle (or sec/cycle).
     What is the period of the pendulum illustrated in this graph? __________________________


3. Frequency is a measure of the number of cycles per second (cycles/sec, or Hertz).

           a) What is the relationship between frequency and period? How do you know?




           b) Calculate the frequency of your pendulum. Show all of your work. Frequency is
              measured in Hertz (Hz, or cycles/sec).




           c) Calculate the number of cycles your pendulum will have in 20 seconds. Show your
              work below.



                                             92
   4. Now label the following on your graph:

           a. equilibrium point (or where the rest position of the pendulum is)
           b. amplitude (or the maximum distance of the pendulum from its rest position)
           c. wave crest (high point or peak)

           d. wave trough (low point or valley)

           e. wavelength (or the distance from crest to crest OR from trough to trough)
               NOTE: wavelength is also the length for one full crest and one full trough.

           f. Check your textbook on page 437 to see if your labels are correct. If you are 100%
              right, put a star next to letter (f). If any of your labels are incorrect, use a different color
              pen or pencil to fix the labels.



Part D

Write a sentence about the effect of changing each variable on the period of the pendulum. Write a
second sentence explaining how your data supports the statement made about each variable.
For example:
      “We found that changing _________ had _____ effect on the period of the pendulum. We can conclude
      this because when we changed ___________ from ___ to ___ the period changed from ____ to ____.”

     Amplitude




     Mass of Pendulum




     Length of Pendulum




                                                         93
LAB: Observing Properties of Waves, Using a Slinky!

Part 1 – Properties of Waves
While one team member holds one end of the Slinky on the floor,                                  pull on
the other end until the spring is stretched to a reasonable length. Please do not overstretch the slinky!
At one end, the slinky must be held firmly so that it cannot move. The person at the other end will
generate a pulse with the slinky by flicking his or her wrist. To form a pulse, grasp a loop at one end of
the slinky and displace it to one side by a quick back-and-forth motion of the hand. Remember, the
slinky should only be moved side-to-side, NOT up-and-down; it will tangle! Look at the pulse as it
moves along the slinky and answer the following questions:

   1. What happens to the shape and size of a pulse on the slinky as it travels towards your partner?



   2. What is the distance between you and your partner (1 square tile = 1 foot)? How long (in
      seconds) does it take the pulse to travel from you to your partner (one way)?

                        distance:__________________              time: ___________________

   3. Using this data, determine the speed of the pulse. Show your work, and unit!




   4. Does the speed of the pulse depend on the size of the pulse (meaning how far back you ―flick‖
      your wrist)? Conduct a short experiment to find out, recording all data in the table below.

       Independent variable: ________________ Dependent variable:_______________

             size of pulse            distance                  time (in sec)   speed (in ft/sec)
                                should be kept constant!
           Small (1 block)

          Medium (2blocks)

           Large (3 blocks)

The pulse you created is called an incident pulse, which means it travels in only one direction. Based
on your data, is there any significant change in the speed of the incident pulse based on its size?
Explain.




                                                           94
   5. When the pulse travels to one end, it will turn around and come back. This is called reflection;
      you see a reflected pulse. This time use the same LARGE pulse used before. How does the
      speed of the reflected pulse compare to the speed of the incident pulse in #4? Conduct a short
      experiment to find out, recording all data in the table.

       HINT: If you are having trouble getting good times for the reflected pulse, calculate the time down and
       back, and then subtract the time from your data table in number 4 for the large pulse size!

                Trial                  distance                    time (in sec)     speed (in ft/sec)
                                 should be kept constant!
                   1

                   2

                   3


                                                                 Average of 3 trials: _________________

       Based on your data, how does the speed of the reflected pulse (#5) compare to the speed of the
       large incident pulse (#4)?



   6. Ideally, after reflection the speed, size, and shape of the pulse stays the same! Are your results
      consistent with this? If not, suggest why.




Now, you will need to change the tension in your slinky. Increasing the tension in the slinky decreases
the density (amount of material) through which the pulse travels. Likewise, decreasing the tension in
the slinky increases the density (amount of material) through which the pulse travels.
    7. What could you do, without changing your location on the floor, to decrease the tension in
        the slinky?


       Increase the tension in the slinky?



   8. Does altering the tension in the slinky change the shape of the pulse? Describe what you see.




                                                            95
   9. Does altering the tension in the slinky change the speed of the pulse? Conduct a short
      experiment to find out, recording all data in the table below.

       IV: _______________________________ DV: _______________________________

              tension            density?              distance               time (in sec)         speed (in ft/sec)
                                                 should be kept constant!
          Lot of tension
            Medium
             tension
          Little tension

       Based on your data, does altering the tension in the slinky change the speed of the pulse?
       Explain.



Still holding the far end of the slinky firmly against the floor, create a single pulse disturbance in your
stretched slinky. Observe the shape of the pulse as it is reflected from the fixed end.



   10. What happens when a pulse reflects after striking a fixed end of the slinky? Is the reflected
       pulse upside down (USD) or right side up (RSU)? Meaning, is the pulse reflected back on the
       opposite side (USD) or on the same side (RSU)?




                    BEFORE                                                  AFTER
      (Draw incident pulse. Indicate direction          (Draw reflected pulse. Indicate direction
                   with arrow)                                        with arrow)

Now tie a piece of string about 1 meter in length to one end of the slinky. While your partner holds the
end of the string, generate a single pulse from the other end of the slinky. Observe the way the pulse is
reflected from the free end.

   11. What happens when a pulse reflects after striking a free end of the slinky? Is the reflected
       pulse upside down (USD) or right side up (RSU)?




                    BEFORE                                            AFTER
      (Draw incident pulse. Indicate direction       (Draw reflected pulse. Indicate direction
                   with arrow)                                     with arrow)


 Compare your answers from questions 10 and 11 and suggest an explanation for your observations.

                                                          96
Part 2 – Relationship between Frequency and Wavelength

Instead of sending single pulses down the slinky, try to generate a wave train (many pulses) by having
one person move their hand back and forth with a constant frequency. The other person should keep
one end of the slinky fixed, or held in place.

   1. Generate a low frequency wave train. Remember that frequency is the number of cycles (or
      waves) per second. Describe the resulting wavelength – are the wavelengths short or long?
      Draw what the low frequency wave train looks like.




   2. Now generate a high frequency wave train. Describe the resulting wavelength – are the
      wavelengths short or long? Draw what the high frequency wave train looks like.

   3. Based on your observations, what changes in the wavelength do you see when you increase the
      frequency? When you decrease the frequency? Explain your results.




Part 3 – Challenge Exercise!
      How can you change the frequency of a wave?

      How can you change the speed of a wave?

      How can you change the amplitude of a wave?

      How can you change the wavelength of a wave?


Practice generating waves with the characteristics in the table below. Call your instructor over when you
are ready to demonstrate each of these. S/he will randomly choose one of these for you to demonstrate. You
will earn points based on your performance and ability to answer any questions asked of your team.

        Frequency              Speed             Amplitude           Wavelength         Teacher Check

            high                 fast                large
            low                 slow                 large
                                 fast                small               long
                                slow                 small               short




                                                   97
Part 4 – Transverse & Longitudinal Waves

   1. The picture below illustrates a transverse wave. Keeping the slinky on the floor, try to make a
      transverse wave that looks like the one below.
                                                                    direction of wave




          a) In which direction does the wave move?      HORIZONTAL          VERTICAL

          b) In which direction do the coils of the slinky move?
                HORIZONTAL          VERTICAL

          c) Make a statement about a transverse wave, relating the direction of motion of the
             separate coils of the slinky to the path taken by the wave:

                     ―A transverse wave has oscillations _______________________ to the direction
                     the wave moves.
   2. The picture below illustrates a longitudinal wave. Keeping the slinky on the floor, try to make
      a longitudinal wave that looks like the one below.
                                                                            direction of wave




          a) In which direction does the wave move?      HORIZONTAL          VERTICAL

          b) In which direction do the coils of the slinky move?
                  HORIZONTAL         VERTICAL

          c) Make a statement about a longitudinal wave, relating the direction of motion of the
             separate coils of the slinky to the path taken by the wave:

                      ―A longitudinal wave has oscillations ____________________ to the direction
                     the wave moves.‖




                                                 98
Lab Analysis
  1. In Part One, how should the speed of the reflected pulse compare to the speed of the incident
     pulse? Does your data from number 5 support this? If not, suggest a reason(s) why.




  2. You learned that the size of the pulse does NOT affect speed.
              a) What is the relationship between tension in the slinky and the density of the
                 material? Explain.



              b) What is the relationship between tension in the slinky and the speed of the pulses?
                 Explain.



              c) Predict what would affect the speed of a pulse through a material.



  3. When you create a pulse in the slinky,
             In what direction(s) does the slinky itself move?


             Which way does the pulse move in relation to the slinky? Try to use the word perpendicular in
              your answer.


  4. Does the slinky itself ever cover any distance? Explain your answer.



  5. Based on your observations in Part Two, what is the relationship between frequency and
     wavelength? Explain what you observed.




  6. Could you show how to find the speed of a wave (v) using its frequency (f) and wavelength (λ)
     in a three variable equation? Hint! Read pages 438-439 in your textbook!




                                                     99
7. In Part Four, you used the slinky to make a transverse wave and a longitudinal wave. Read
   page 436 in your textbook. Then in a different color, put a star by the letters in Part Four you
   have correct. If any information is incorrect based on your reading, fix it in a different color!

8. Read the following quote before answering the question below:
           “The essentially new thing here is that for the first time we consider the motion of something
           which is not matter, but energy propagated through matter.”
                                                            -Albert Einstein and Leopold Infeld

   What is transferred in a wave – matter, energy, or both? Explain your answer, using what you
   observed with the slinky as an example.




                                                 100
  MiniLab: Interference & Superposition

Purpose
The goal of this lab is for two members of your team (at                                 opposite
ends of the slinky) to send pulses at the same time to                                   investigate
what happens when waves collide; a process known as
interference.


Part A
   1. To begin, one team member will send a BIG pulse and the other should send a little pulse
       down the slinky. Both pulses should be on the same side. When the two pulses meet on the
       slinky, do they bounce off of each other or pass through each other? Support your answer based
       on your observations.




   2. When the pulses meet on the slinky, how does the size of the combined pulse compare to the
      size of the individual pulses? Sketch your answer in the box below (in pencil!) by showing
      what the slinky looks like as the pulses meet in the middle.




                                                 101
Part B
   1. Again, one team member will send a BIG pulse and the other should send a little pulse down
       the slinky. This time, pulses should be on opposite sides. When the two pulses meet on the
       slinky, do they bounce off of each other or pass through each other? Support your answer based
       on your observations.




   2. When the pulses meet on the slinky, how does the size of the combined pulse compare to the
      size of the individual pulses? On which side of the slinky is the combined pulse? Sketch your
      answer in the box below (in pencil!) by showing what the slinky looks like as the pulses meet
      in the middle.




MiniLab Analysis
Read pages 444-445 in your textbook. Then answer the questions below, in complete sentences.

   1. What is it called when two wave pulses meet to make a single large pulse? What side of the
      equilibrium point (same or opposite) do the pulses have to be on to make a larger amplitude?


   2. Was it Part A or Part B in the lab that illustrated this interference pattern? Explain your
      observations.




                                                  102
3. What is it called when two waves pulses meet and the wave flattens out? What side of the
   equilibrium point (same or opposite) do the pulses have to be on to cancel each other out?




4. Was it Part A or Part B in the lab that illustrated this interference pattern? Explain your
   observations.




5. Describe the superposition principle. Then discuss why in reality, single waves are quite rare.




6. In the lab, you should have seen that after the pulses met in the middle, they separated again
   and traveled off on their own. Why does this happen? Think in terms of energy!




                                               103
BASIC WAVE PROPERTIES – SLINKY LAB DISCUSSION

What does this quote mean in relation to waves?
       “The essentially new thing here is that for the first time we
       consider the motion of something which is not matter, but energy
       propagated through matter.” (-Albert Einstein and Leopold Infield)

What does matter do in a wave?

.
KEY IDEA:


What did we learn in the Slinky Lab?

Properties of Waves




Interference of Waves




Relationship between Frequency and Wavelength




Passage from one medium to another




Note: All of these properties work for all types of waves




                                                  104
TYPES   OF   WAVES – PEOPLE DEMO DISCUSSION
Transverse Waves




Longitudinal Waves




                                    105
                                    LAB: Standing Waves
Purpose
The goal of this lab is for your team to investigate standing                             waves. These
waves are the product of interference, or when waves                                      collide.
However, standing waves are unique because they occur in                                  a confined
space.


Part A – Learning about standing waves
You will first read p. 440 in the textbook to learn more about standing waves and how they are created.

   3. What is a standing wave, according to your textbook?


   4. A classic way to experiment with standing waves is using a _____________________.

   5. Sketch the first five harmonics of a vibrating string, as shown in the picture on the left in your
      textbook.




       a) The lowest natural frequency, labeled ―1,‖ is called the _____________________.

       b) The other natural frequencies, labeled ―2‖ through ―5‖ are called ______________.
       c) How can you determine which harmonic is present?



   6. Draw the third harmonic and label the nodes and antinodes.




       a) Nodes are points where the string…

       b) Antinodes are points where the string…

   7. Why do you only see a wave-shaped blur with a standing wave? If you could ―pause‖ the string
      at any one moment in time, what would you see?


                                                                           teacher initials



                                                  106
Part B – Creating standing waves in the lab
   1. You will now create standing waves using the slinky. Try shaking the slinky back and forth,
       keeping one end fixed. You will produce waves that will travel down to the other end and be
       reflected back. As you continue to vibrate the slinky, waves traveling in both directions will be
       present. Quite a jumble results because the waves traveling in opposite directions interfere with
       each other.

                What is meant by the term ―interference‖?



   2. Now try shaking the slinky with specific frequencies (also known as resonant frequencies),
      where the regions of constructive and destructive interference will occur at certain fixed points,
      and a standing wave will be produced. The points of complete destructive interference are
      called nodes and the points of maximum constructive interference are called antinodes.

       a) Try to set up a standing wave on your slinky. Sketch the wave pattern below. What
          harmonic is illustrated?




       b) How does the distance between adjacent nodes compare to the distance between adjacent
          antinodes? equal? bigger? smaller?



       c) A basic property of a standing wave pattern is that the distance between adjacent nodes is
          equal to ½ a wavelength. Show (through a drawing) and explain why this is so. Remember
          what you have learned about waves so far.




   3. The simplest, or fundamental, frequency of vibration for a string (or in this case a slinky) fixed
      at both ends is a standing wave with a node at each end and one antinode in the middle.

       a) Produce a standing wave on your slinky that corresponds to this fundamental frequency.
          The fundamental is also called the first harmonic. Sketch the wave pattern below.




       b) Now DOUBLE the frequency you used the produce the pattern in (a) above. Sketch the
          resulting wave pattern below. This pattern is called the second harmonic.




                                                  107
       c) How did the wavelength of the second harmonic compare to that of the first harmonic?
          shorter? longer?




       d) Try to obtain the third and fourth harmonics. How do the frequencies of these harmonics
          compare to the frequency you used for the fundamental?



            CHECK OUT! When you are finished, call your instructor over to verify that
            you have completed the lab successfully. To do so, your team must be able to
              demonstrate a standing wave AND point out the node(s) and antinode(s).

In Summary…

      You can get a standing wave if you have 2 identical waves traveling in opposite directions on
       the same medium. This makes a standing wave an interference pattern.

      They are called standing waves because they appear to _______________________, or do not
       appear to propagate down the medium.

        Point A in the medium that oscillates back                                        and forth
         is

           called an _________________________.

        Point B in the medium with NO displacement                                        is called a
         ___________________________.

STANDING WAVES DEMO!

NOTE: A vibrating string moves so fast that your eye sees a wave-shaped blur. At any one moment
however, the string is in ONLY one place within the blur. We can verify this by using a standing wave
generator to create standing waves and then shining a strobe light on it to verify the movement of the
string!




                                                 108
Ranking Exercises…Waves
Rank and explain! For each not only do the ranking from smallest to greatest, but also explain why
you chose that ranking.

     1. Rank these waves that all occur on the same medium, in terms of:


 A                                              B



 C                                              D



Rank these waves (that are all traveling in the same medium) in terms of the following. For ties, put in
parentheses.


     1. Wavelength: biggest ______ _____ _____ _____ smallest
        Explain:



     2. Frequency: biggest ______ _____ _____ _____ smallest
        Explain:



     3. Period: biggest ______ _____ _____ _____ smallest
        Explain:



     4. Speed: biggest ______ _____ _____ _____ smallest
        Explain:




                                                  109
                  Properties of Waves Problems
                                 Homework

PERIOD AND FREQUENCY
The period of a pendulum is the time it takes to move through one cycle. As the ball on the string is
pulled to one side and then let go, the ball moves to the side opposite the starting place and then
returns to the start. This entire motion equals one cycle.

Frequency is a term that refers to how many cycles can occur in one second. For example, the
frequency of the sound wave that corresponds to the musical note ―A‖ is 440 cycles per second or 440
hertz. The unit hertz (Hz) is defined as the number of cycles per second.

The terms period and frequency are related by the following equation:




Use the equations above to solve the following problems. Show all of your work!

1. A string vibrates at a frequency of 20 Hz. What is its period?




2. A speaker vibrates at a frequency of 200 Hz. What is its period?




3. A pendulum takes 10 seconds to swing through 2 complete cycles.

a. How long does it take to complete one cycle?




b. What is its period?




c. What is its frequency in Hertz?




                                                  110
 WAVES: PART A
 A wave carries energy from one place to another and is produced when matter oscillates. A high point of a wave
 is called a crest. A low point is called a trough. The amplitude of a wave is half the distance from a crest to a
 trough. The distance from one crest to the next is called the wavelength. Wavelength can also be measured from
 trough to trough or from any point on the wave to the next place where that point occurs..

 4. On the graphic at right label the following parts of a
 wave: one wavelength, half of a wavelength, the
 amplitude, a crest, trough and equilibrium.

 a. How many wavelengths are represented in the wave
 above?


 b. What is the amplitude of the wave shown above in centimeters?


 PART B
       5. Look at graphs I – VI below and answer the following questions for each in the spaces
          provided under the graphs.
             a. How many cycles (waves) are shown?
             b. What is the amplitude?
             c. What is the period (T) in seconds?
             d. What is the frequency (f) in Hertz ?


  I.                                                          II.




         a. _________       b. _________                                 a. _________        b. _________
         c. _________       d. _________                                 c. _________        d. _________



III.                                                          IV.




         a. _________       b. _________                               a. _________        b. _________
         c. _________       d. _________                               c. _________        d. _________

                                                       111
PART C
6. Use the grids below to draw the following waves. Be sure to label the y-axis to indicate the
measurement scale. The x-axis will represent wavelength or time

a. Draw 3 wave cycles with an amplitude of 1 cm and a wavelength of 2 cm.




b. Draw 4 wave cycles with an amplitude of 1.5 cm and a time of 3 sec




PART D     Wave Speed Problems: v = fλ or v = λ/T or T= 1/f or f = 1/T
7. a. A water wave has a frequency of 2 hertz and a wavelength of 5 meters. Calculate its
speed.



   b.    What is the period of the wave?



8. A wave has a speed of 50 m/sec and a frequency of 10 Hz. Calculate its wavelength.



9. A wave has a speed of 30 m/sec and a wavelength of 3 meters. Calculate its frequency.


10. A wave has a period of 2 seconds and a wavelength of 4 meters. Note: Recall that the
frequency of a wave equals 1/period and the period of a wave equals 1/frequency.

   a. Calculate its frequency

                                             112
   b. Calculate its speed.



11. A sound wave travels at 330 m/sec and has a wavelength of 2 meters. Calculate its
frequency and period.




12. What determines the speed of a wave?




                                            113
114
Warm-up - Standing Wave Patterns


              115
   1. In the table below, draw the picture of what the standing wave looks like for each harmonic.
      Label the nodes and antinodes.

       What do you notice about the harmonic number and the number of nodes and antinodes?
   _______________________________________________________________________________
   ___________________________________________________________

   2. In the table below, the frequency of the first harmonic is given.
          a. Predict the frequencies of the 2nd through 4th harmonic by filling in the table.

         b. What is the relationship between the frequency of the fundamental and frequencies of
            the second, third, and fourth?
   _______________________________________________________________________________
   ___________________________________________________________

   3. In the table, indicate the number of wavelengths for each harmonic. The fundamental is done
      for you. Give an explanation for why those numbers are correct.
   _______________________________________________________________________________
   ___________________________________________________________

   4. Why are standing waves important?
   _______________________________________________________________________________
   ___________________________________________________________


Properties of Standing Waves
   Harmonic                      Picture                    Frequency             # of
                                                                               Wavelengths
                                                                                  ½ of a
1st (fundamental)                                              8 Hz
                                                                                wavelength


       2nd                                                                     1 wavelength


       3rd                                                                    1.5 wavelengths


       4th                                                                     2 wavelengths




                                                  116
                WAVE PROPAGATION IN WATER

Purpose: In this investigation you see how waves move in water,                               a much
different medium then a slinky!

Procedure
Plane and Circular Waves
   1. Fill the tray with about 0.5 cm of colored water. The color helps you see the waves. Put white
       paper under the tray to see the waves better.
   2. Roll the wave tube forward about 1 cm in a smooth motion. This launches a nearly straight
       wave called a plane wave.
   3. Next, poke the surface of the water with your fingertip. Disturbing a single point on the surface
       of the water makes a circular wave.

Reflection – waves bounced off and go in a new direction.
        1. Put two metal blocks side by side so they are spanning the width of the wave tray. Position
           them so they are in the middle of the tray.
        2. Make a plane wave pulse with the dowel. Record your observations about what happens
           when the wave strikes the barrier.



                 a. What does the reflected wave pulse look like? You may want to draw pictures.



       3. Now make many plane wave pulses with the dowel. Keep doing that until the waves start
          reflecting on themselves. Record your observations about what happens when many waves
          are reflected.

           b.    Do the waves appear to interfere with each other? How could you tell?



       4. Now make many plane wave pulses at a certain frequency. Increase the frequency.
          Describe what happens to the wavelength as you increase the frequency.



       5. Can you find the frequency in which the waves appear to be standing still (standing wave!)?
          Show your instructor!


Diffraction – waves bend around corners or pass through openings.
    1. Arrange the two blocks so have a 1 cm opening between them. They should be in the middle of
       the wave tray.
    2. Make many plane waves that move toward the blocks. Observe what happens to the wave that
       goes through the opening. Record your observations.

                                                  117
Analysis Questions – Please answer these questions in COMPLETE sentences.
  1. The wave front of a water wave is an imaginary line drawn to show the shape of the wave.
      Draw a sketch that shows the wave front of your plane wave. Draw an arrow in your sketch that
      shows the direction the wave moves.


   2. Is the wave front parallel or perpendicular to the direction the wave moves in a plane wave?


   3. Draw another sketch that shows the circular wave fronts and include at least four arrows that
      show the direction in which each part of the wave moves.



   4. Are the wave fronts more parallel or perpendicular to the direction in which the circular wave
      moves? (Pick one point of the circle: is the wave move perpendicular or parallel from that
      point.)



   5. Sketch the shape of the wave fronts before and after the wave passes through the 1 cm opening.
      (See page 443 of your textbook for a hint!)



   6. How did the plane wave change shape when it passes through the opening between the blocks?



   7. When a wave passes through a narrow opening, the wave changes shape and bends around
      corners. This is called diffraction. Sound travels in waves. Diffraction explains why you can
      hear someone in the other room even though the door is only open a tiny crack. Think of
      another example where sound might be diffracted.


   8. Add diffraction, plane wave, and circular wave to your list of vocabulary words




                                                118
119
120
121
122
Exploration - Sound and Resonance

       Vocab to know:

       Resonance:

       Natural Frequency:

       Sympathetic Resonance:

       Fundamental Wave:

Station 1: Metal Grate on a String
Pick up the grate by the strings; knock it against the side of a table.

    Summary of Your Observations:
     a. Write a brief description of the sound that you hear.


       b. What medium does the sound of the vibrating grate travel through to reach your ears?

Now, with your index fingers, press the ends of the strings against your ear on that little flap of flesh that
protrudes over the opening of the ear. Again swing the grate into the side of a table.
       c. Write a brief description of the sound that you hear with the strings pressed against your ears.

       d. What medium does the sound of the vibrating grate travel through to reach your ears?

       e. Which medium is the better resonator?

Station 2: Boomwackers
Lightly tap the boomwackers on the table top and listen to the pitch for each tube.

       a. Which tube produces the lowest pitch? Highest pitch?


Add the cap to each tube and repeat tapping.
       b. How does adding the cap change the pitch played by the tube?

       c. Given that the tube without cap produces ½ wavelength compared to the tube with the cap that
          produces ¼ wavelength, describe what happens to the wave frequency when you add the cap?


       d. Try to play a simple tune. Write the notes…by color.




                                                            123
Station 3: Talking Tapes
Run your thumb nail down the side of the red tape with ridges on it. Use the one without the cup first.
           a. What do you hear?

        Now try the one with the cup.

            b. What do you hear?

            c. What is the resonator? In terms of oscillators, explain why this happens.

Station 4: Cone-A-Graph
      Turn the record player on speed 33. Carefully and gently place the pin in the cone as shown:
                      Pin it here



                a. Describe the sound that you hear.


                b. What amplifies the pin‘s oscillation?


        Put the pin in a smaller cone.

                c. Compare the sound to the bigger cone.



Station 5: Music Box – BE CAREFUL!
      Wind the music box mechanism and hold it in the air.
             a. Do you actually hear music or just the ‗plinker‘ in the air?

        Now place the mechanism back in the box while it is playing.

                b. Do you actually hear music or just the ‗plinker‘ on the table?


                c. What is the resonator at this station?


                d. Relate this application to speakers.




                                                              124
Station 6: Kazoos
      Look at the kazoo.
             a. What part is the oscillator? What is the purpose of                          this?

              b. What part is the resonator?


              c. If there are extras, take a kazoo and practice playing with it.

Station 7: Twirl- A- Tube
Twirl a tube at various speeds. Find the fundamental frequency (the lowest note).
              a. How do you have to twirl the tube to get the fundamental frequency?


              b. How do you need to twirl the tube to get the different notes?

              c. Describe the tone with the slow twirl.


              d. Describe the tone with the fast twirl.


Station 8: Cricket Anyone
While holding the wooden cricket, move the stick back and forth over the ridges on the cricket.

              a. Describe what you hear.

              b. What causes the sound?

              c. Why is the cricket semi-hollow like a guitar?


Station 9: Palm Pipes
      Tap the pipes on your hand to play them. Practice a song 

              a. Which pipes produce the lowest pitch? Highest?


       Inside these pipes, standing waves are produced. This is an OPEN pipe so the fundamental standing
       wave created has an antinode on either end and one node which lies in the middle.
       b. Sketch this wave below.                           Palm Pipe




                                                          125
Station 10: Star Wars
      Try to produce a sound that sounds like special effects in a Star Wars movie.
              a. Could you produce that sound without the cups on the end of the spring?

                b. What is the role of the cups on the end of the spring?


       Station 11: What’s the big Whoop?
       Have someone sit on the cushion.

           a. How is the sound produced? What medium does the sound travel through?

       This time just squeeze the cushion without covering the small hole in the center.

           b. How is the sound different?



           c. Explain in terms of the medium it is traveling through.




Station 12: Resonating Guitar
       This is Mrs. Riendeau‘s guitar so be nice or she‘ll be not so nice!!

       Pluck a string on the guitar.
          a. Did you produce a standing or traveling wave?

       Pluck the string on the table.

           b. Describe the difference in sound.


           c. What is the resonator in each instance?


       Now, place your finger at one of the frets of the guitar to shorten a string Pluck the string now. (Look! A
       standing wave!!!)

           d. What happened to the pitch when the string was shortened?


           e. How did the wavelength of the standing wave change? Shorten? Lengthen?


           f.   Make a statement relating wavelength, pitch , frequency!




                                                              126
                                                  Resonance
Station 13: Tuning Forks with Resonators
       Face the open ends of the boxes towards each other.

       Predict: What will happen when you strike ONE of the forks with the rubber mallet?


       Strike one of the forks with the rubber mallet provided. Dampen (stop it from vibrating) the one you
       struck after a few seconds.

                  a. Was your prediction correct? Describe what you hear to support this.


       Stop it from vibrating then repeat the strike with the mallet, only this time suspend the ping-pong ball
       so it is lightly touching the 2nd tuning fork (the one you didn‘t strike).

                  b. Record your observations of the ping pong.

       Attach the special metal clip Strike the tuning fork without the metal ―clip,‖ and after a moment,
       dampen it.

                  c. What do you hear? Why do you think this happened?


                  d. What is the purpose of the wooden box?


Station 14: Identifying Natural Frequencies
         Close your eyes while your lab partner drops several objects on the floor, one at a time. Try to
         identify each of the objects by the sound of its impact.

                  a. Record your results and determine the percentage of objects correctly identified.



                  b. Identify the physical property where you listening for - natural resonance, natural
                     frequency, or natural amplitude.




                                                          127
Station 15: Dude Magic

      Be gentle with Mrs. Riendeau‘s dude!!! Provide an oscillation to get it in motion.

      What is the evidence that you were able to get the dude to reach its natural frequency?

Station 16: Reflect it

      Get the reflector oscillating at its natural frequency.
             a. Sketch its motion.

      Increase the frequency until you reach the second harmonic.
             b. Sketch the motion now.

Station 17: Saw Blade Oscillations

      Observe the 2 saw blades attached to the block of wood. Note that one saw blade is longer than the
      other. By only moving the board back and forth on the table, make the shorter saw blade oscillate with
      a large amplitude.

             a. What do you notice about the larger saw blade as the smaller one is oscillating?



      Now repeat the process by get the longer blade to oscillate with a large amplitude.
            b. What do you notice about the smaller saw blade as the larger one is oscillating?



             c. What variable did you change to get one board to oscillate while the other rested?




                                                           128
Nikola Tesla (1856 - 1943) - Master of Resonance
It was an innocent experiment. Tesla had attached a small vibrator to an
iron column in his New York City laboratory and started it vibrating.
At certain frequencies specific pieces of equipment in the room would
jiggle. Change the frequency and the jiggle would move to another part
of the room. Unfortunately, he hadn't accounted for the fact that the
column ran downward into the foundation beneath the building. His
vibrations were being transmitted all over Manhattan.
For Tesla, the first hint of trouble came when the walls and floor began
to heave (ref 1). He stopped the experiment just as the police crashed
through the door. It seems he'd started a small earthquake in his
neighborhood smashing windows, swayed buildings, and sending
panicked neighbors rushing into the streets. The police had frequently
responded to complaints about Tesla's unusual activities.



Although Tesla was not the first to discover resonance he was obsessed with it and created some of the most
incredible demonstrations of it ever seen. He studied both mechanical and electrical versions. In the process he
created an artificial earthquake, numerous artificial lightning storms, knocked an entire power plant off line in
Colorado, and nearly caused the steel frame of a sky scraper under construction in Manhattan to collapse. Tesla
realized that the principles of resonance could be used to transmit and receive radio messages well before
Marconi. In fact, many knowledgeable sources now credit Tesla as the inventor of radio rather than Marconi. This
includes the Supreme Court which in 1943 ruled that Tesla's radio patents had preceded all others including
Marconi's .
Tesla was a one-of-a-kind neurotic genius who had a profound influence on our technology and culture. He was
obsessed with germs and the number three yet his inventions almost single handedly enabled the creation of our
modern AC power distribution system. He was a contemporary of Edison and for a time worked for the famous
inventor. Unlike Edison (who Tesla considered something of a bumpkin), Tesla used theory and calculations as
well as experimentation to conduct his research and was the more modern of the two in his approach. He was also
far more interested in pursuing his inventions for their own sake than in becoming rich and famous.
Unfortunately, Tesla's obsession with pursuing grand ideas and projects proved to be his undoing. He became
convinced that energy could be transmitted through the air without wires and spent a small fortune on a
demonstration project. He built a giant Tesla coil in Colorado Springs which used electrical resonance to build up
incredibly high voltages and caused fantastic lightning shows. Unfortunately, his dream of transmitting wireless
power was never commercialized and, partly because of it, Tesla ended dying a poor man .

The mad scientist stereotype came from Tesla. Tesla's Manhattan
Lab was a mysterious place with buzzing electric arcs, eerie
lighting, and bizarre contraptions. The lab undoubtedly inspired
mad scientist scenes in 1930's horror pictures such as
Frankenstein, with Boris Karloff, in which high voltage arcs are
used to give the monster life. Although Tesla never attempted to
create life he did create the first radio controlled robotic vehicles
and claimed that one day robots would free humanity of drudgery
work. He also claimed to have invented a powerful death beam.
For entertainment, Tesla once convinced his good friend Mark
Twain to test out a vibrating platform in his Manhattan lab. Twain

                                                  129
took him up on the offer and found it to his liking. When Tesla
commanded Twain to come down off the platform Twain refused
because he was having a good time. A few minutes later Twain ran
from the device. It seems that Tesla had deliberately neglected to
tell Twain that the vibration tended to cause diarrhea.
Had Tesla been less eccentric and more interested in personal fortune he would
have avoided the grandiose projects which were his undoing. If he had simply
avoided making outrageous statements, he would have had more scientific
credibility and easily overshadowed Edison. Today, Tesla would be far more
famous and the subject of resonance would probably receive far more attention in
science textbooks. Resonance was certainly one of Tesla's greatest passions and,
like Tesla, seems almost too mysterious to be real.




                                             130
Freshman Physics       Name:_______________________________________ Per:___
ACT-Waves of a Heartbeat                          Due Date:_________________

The Heart Rate
       A normal heart beat is initiated by a small pulse of electric current. This tiny electric "shock"
spreads rapidly in the heart and makes the heart muscle contract. If the whole heart muscle
contracted at the same time, there would be no pumping effect. Therefore the electric activity starts
at the top of the heart and spreads down, and then up again, causing the heart muscle to contract in
an optimal way for pumping blood. A heartbeat is a two-part pumping action.
                                                                              Pacemaker (S-A node)
Where does the electricity come from?
         In the heart there are cells specialized in producing electricity.
These are called pacemaker cells and are located in a part of the
heart called the sinoatrial node (S-A node). They produce electricity
by quickly changing their electrical charge from negative to positive and
back. Because of the heart muscle cell's ability to "spread" its electric
charge to adjacent heart muscle cells, this initial wave will be enough to
start a chain reaction.
     The first electric wave in a heartbeat is initiated at the top of the
heart. As blood collects in the upper chambers (atria), the heart's              RIGHT SIDE LEFT SIDE
natural pacemaker (the SA node) sends out an electrical signal that causes
the atria to contract. When the heart muscle contracts or beats (called systole), it pumps
blood to the ventricles. The ventricles then contract to propel blood out of the heart. Then the
heart muscle relaxes (called diastole) before the next heartbeat therefore allowing blood to
fill up the heart again.

The Electrocardiogram
        The electrocardiogram or ECG (sometimes called EKG) is today used worldwide as a
relatively simple way of diagnosing heart conditions. An electrocardiogram is a recording of
the small electric waves being generated during heart activity.
        The electric currents in the heart have been measured for more than a hundred years,
but the fundamental function of the ECG as we know it today was developed by the Dutch
scientist Willem Einthoven in the beginning of the 20th century. In 1924 Einthoven was
awarded the Nobel Prize in Physiology or Medicine "... for his discovery of the mechanism of
the electrocardiogram." Through ECG analysis, it is possible to trace the conduction through
the heart, estimate the size and orientation of the heart, and even to locate the regions of the
heart which have suffered injury, ischemia (oxygen deprivation), or necrosis (tissue death).
Here are a few examples of what these electrical impulses would look like as measured by an
                                               ECG machine:




                                                  131
QUESTIONS:
  1. How does the S-A node (pacemaker) regulate heart rates in normal individuals? (i.e.-
     what kind of message does it send to the heart muscles?)



   2. Why doesn’t the heart contract all at once?



   3. What types of actions/substances could affect an individual’s heart rate? List 3
      examples and include what it would do to the heart rate (increase/decrease).
         a.



         b.



         c.



   4. What does an electrocardiogram show?



   5. How would you know if one complete heart beat cycle has been completed from an
      ECG?


So what do the waves mean??
        When the heart muscle is
at rest, the pacemaker cells are
negatively charged and when the
heart contracts they are
positively charged. When a
positive wave is recorded by a
positive electrode, the ECG
curve will be pointing upwards
and vice versa. There are a few
ways doctors can attach the
electrodes that measure the
electrical impulse, so sometimes
these ECGs can look different.
Normal heartbeats are so
consistent doctors even know
                                             132
what is happening in the heart during each ―wave‖ that is produced by these electrical
impulses:
ECG Waves and Intervals:
What do they mean?
    The P-Wave: The impulse across the atria to the A-V Node (middle of the heart)
    The QRS Complex: The impulse as it travels across the ventricles (lower chambers)
    The T-Wave: The repolarization of the ventricles

Paging Dr. Frysics!! Paging Dr. Frysics!!
       Let’s try your hand at interpreting an ECG…Just like our ticker tapes from earlier in the
year, an ECG is created by punctuated ink marks on paper. However, this paper is fed
through the machine at a constant speed so heart rate can be determined based on how
much space (or time) has elapsed between successive P-P crests or R-R crests.

       Each little line represents 0.04 seconds and each larger line represents 0.20 seconds.




For regular rhythm, the heart rate can be calculated by:
                            1 R-R cycle               60 sec
heart rate (bpm) = -------------------------- * -------------------
                           R-R interval (sec)          1min



                     R-R interval (sec)
Period        =      --------------------------
                          1 R-R cycle


                                                  133
For the following ECG rhythm strips, label the P, QRS complex and T waves.




   6.

         a. What is the period of this heart beat? (T=time (s)/# cycles)




         b. What is the frequency (heart rate), in bpm, of this heart beat?




   7.

         a. What is the period of this heart beat? (T=time (s)/# cycles)



         b. What is the frequency (heart rate), in bpm, of this heart beat?




   8.
         a. What is the period of this heart beat? (T=time (s)/# cycles)



         b. What is the frequency (heart rate), in bpm, of this heart beat?


                                            134
TABLE 1 – CARDIAC RYHTHMS
Normal       Normal, adult pulse
Sinus
Rhythm
P-R          0.12 to 0.20
             seconds
QRS Interval 0.04 to 0.12
             seconds
Rate         60 to 100 beats per
             minute
Bradycardia Slowed pulse
Rhythm
P-R          0.12 to 0.20
             seconds
QRS Interval 0.04 to 0.12
             seconds
Rate         less than 60 beats
             per minute
Tachycardia Quickened pulse
Rhythm
P-R          0.12 to 0.20
             seconds
QRS Interval 0.04 to 0.12
             seconds
Rate         more than 100
             beats per minute
Arrhythmia Irregular heart
Rhythm       beats
P-R          0.12 to 0.20
             seconds
QRS Interval 0.04 to 0.12
             seconds
Rate         60 to 100 beats per
             minute with periods
             of irregularity




                                   135
For the following ECGs, indicate the heart rate. If it is fast, slow, or irregular then state what
this condition is called (refer to Table 1). If it is normal, then state normal cardiac rhythm.




       Heart Rate:                                        Condition:




   Heart Rate:                                            Condition:




   Heart Rate:                                            Condition:




   Heart Rate:                                             Condition:




                                                136
Heart Rate:         Condition:




              137
           DEMO LAB: Properties of Sound
Purpose
As a class, we will investigate some of the properties of sound like             frequency and
pitch, and interference of sound waves.

Pre-Lab Questions
   1. What type of wave is sound – longitudinal or transverse? _________________

   2. How is sound created? What is actually vibrating (or oscillating) in a sound wave?

   3. Does sound travel in one direction or in all directions? _____________________

Part A: Frequency and Pitch
As a class we will investigate the relationship between frequency and pitch.

   1. I am going to adjust the frequency control. (Keep the volume at 2 or 3 bars on the volume
      display).
          a) How does the sound change when you adjust the frequency?


           b) What is the relationship between frequency and sound pitch?


   2. How high can you hear? Adjust the frequency according to the table below up to 20,000 Hertz.
      Record whether or not you can hear the sound by putting a check mark in the box if you CAN
      hear the frequency!

                                20
                                50
                               100
                               200
                               400
                               600
                               800
                              1000
                              2000
                              4000
                              6000
                              8000
                            10,000
                            15,000
                            20,000




                                                  138
Part B: Interference of Sound

   1. Two sets of speakers will be used. One set will be at 440 Hz and one will be at 445 Hz. Listen
      to the two sounds simultaneously. You should hear alternating loud and soft sounds. These are
      called beats. What is happening when these two sound waves meet? (Think interference!)




   2. Keep one sound generator at 440 Hz and adjust the frequency of the other between 430 and 450
      Hz. What happens to the frequency of the beats? (Does the sound quiver faster or slower?)




   3. Set both speakers at a frequency of 440 Hz. Do you hear beats at the same frequency? Why or
      why not? (Use in-phase in your answer)




   4. Is there a point where the frequencies are far enough apart where you don‘t hear beats
      anymore? What are the frequencies? What do you think is happening here?



Part C: Analysis Questions
Please answer in complete sentences. You may have to refer to the information in your reading
packet on Interference (26.9) and Beats (26.10)!

   1. Circle the correct answer:
      When frequency of the sound wave ( increases / decreases ),
      the pitch – the highness or lowness of the sound – ( increases / decreases ).
      This is a ( direct / inverse ) relationship.


   2. What do beats sound like? What produces beats?




   3. Below is a graph of the interference of two out-of-phase sound waves – in other words, this is a
      graph of the interference that causes beats. Circle the parts of the graph where the sound would
      be softer. Box the parts of the graph where the sound is louder.


                                                 139
4. Consider the graph above in #3.
      a. Consider the parts of the graph that you label as ―soft.‖ What type of interference is
         happening here – destructive or constructive? Why? Explain your choice.




       b. Consider the parts of the graph that you label as ―loud.‖ What type of interference is
          happening here – destructive or constructive? Why? Explain your choice




       c. What can you say about the relationship between the amplitude of the wave and the
          loudness of the sound?



5. What happens to frequency of the beats when the two sound frequencies are farther apart or
   closer together (for example, 800 Hz plus 845 Hz compared to 800 Hz plus 805 Hz)?




6. When musicians tune their instruments they listen for the frequency of the beats. How do they
   know when they are in tune?




7. Be sure to add the following words to your growing vocabulary list! Pitch, Beats




                                              140
141
Freshman Physics            Name:________________________________________ Per:___
LAB: Rock Band                                         Due Date:_________________

INTRO:
        Many instruments produce sound by vibrating a column of air inside a
tube, e.g. flute, trumpet, and saxophone. As waves of air move inside a
tube, they vibrate in wholes, halves, thirds, fourths, and fifths — fractions in
the harmonic series. This series of harmonics can be played on a garden
hose trumpet, a Whirly-tube, sports bottle straw, as well as any
homemade flute or bugle. There are also instruments in which the sound
is produced as a result of vibrations of a string, e.g. guitars, banjos, and
violins.
        In the pre-lab activity, you will see the scientific properties for each
wave, and hear the sounds of each harmonic on a violin (string), pan pipe
(closed-end tube), and a trumpet (open-end tube). In this lab, you will explore the
relationship between variables for each instrument and its effect on pitch.

PRE-LAB ACTIVITY
Go to this website: http://www.philtulga.com/harmonics.html
Make sure the computer you are using can play sound and has Macromedia Flash Player 7.
There is a link to a free download of the application if you do not have it already installed.

    1. Scroll to the bottom of the page and click the ―Physics‖ button. The ―string‖ instrument
       should be selected also.
    2. For each harmonic number, highlight which note on the musical scale that harmonic
       aligns to.
    3. Finally, draw (with labels) the node and antidotes for the string for that harmonic.

Table 1-Harmonics of a String Instrument
Harmonics Musical Scale           Nodes/Antinodes
1




2




                                              142
3




4




5




6




    4. What do you notice about the pitch of the music as the harmonic number increases?


    5. Click on the ―open-end tube‖. Compare and contrast the sound of each harmonic to
       that of a string instrument.




    6. Click on the ―closed-end tube‖. Compare and contrast the sound of each harmonic to
       that of a string instrument.




                                            143
MATERIALS:
PAN PIPE                                        BOTTLE XYLOPHONE
   2 ft of PVC pipe, ½‖ schedule 40                5-20oz Sobe® bottles (glass)
     sprinkler grade cut as below:                       o Bottle 1-570mL
        o 6-1/16‖ (or 15.4cm)                            o Bottle 2- 390mL
        o 5-3/8‖ (or 13.6cm)                             o Bottle 3-330mL
        o 4-3/4‖ (or 12.0cm)                             o Bottle 5-240mL
        o 3-15/16‖ (or 9.6cm)                            o Bottle 6-180mL
        o 3-7/16‖ (8.7cm)                           100mL graduated cylinder
   5 pennies                                       Water
   2‖ wide duct tape                               Metal Spoon
MELODIC TUBE DRUM                               SIMPLE GUITAR/BANJO
   10ft of ABS pipe, 2‖ diameter                   Piece of wood 32‖x1‖x1/2‖
        o Tube 1-70.4cm                             Nylon fishing line (40-60lb test)
        o Tube 2-62.6 cm                            Permanent Marker
        o Tube 3-55.0cm                             Metric Ruler
        o Tube 5-45.2cm                             4 Large Eye Hook screws
        o Tube 6-40.3cm                             Screwdriver and pliers
   Duct Tape                                       5-Wooden coffee stirrers or thin craft
   Glue                                             sticks cut-1‖ long
   Plastic Top (from baby wipe box)                Sandpaper

PROCEDURE:
Building a 5-note set of Panpipes
   1. Begin by getting approximately 2 feet of 1/2-inch/schedule-40 PVC sprinkler pipe.
   2. Cut the tubing into the five sizes PRECISELY.
   3. Place a penny over one end of each pipe and
      cover each penny with a 2" X 2" square piece
      of duct tape.
   4. Once this is complete, align the untaped
      edges so that they are straight. Have
      someone help you with this!
   5. Wrap about 18 inches of duct tape around the
      set as shown in the diagram below.
   6. Blow across the top of each pipe — it's just
      like blowing on a soda bottle.
   7. Just like any instrument—Practice, Practice, Practice!

Building a Bottle Xylophone
   1. Empty your 5 Sobe® bottles, rinse thoroughly with
      water, and dry completely.
   2. Number your bottles 1, 2, 3, 5, and 6 with a
      permanent marker.
   3. Precisely fill each bottle with the amounts of water
      indicated in the materials section above.
   4. Mark the water level with a permanent marker so
      you can tell if some of your instrument has
      evaporated…

                                             144
   5. Arrange them in order— 1 on your left and 6 on your right.
   6. Gently tap the middle of the bottle with a metal spoon.
   7. Just like any instrument—Practice, Practice, Practice!

Building a 5-note set of Melodic Tube Drums
   1. Begin by getting approximately 10 feet (3 meters) of 2-inch diameter ABS pipe.
   2. Cut the tubing into the five sections listed on the materials list.
   3. Cut five 2-inch circles from a rectangular plastic baby wipe container (use a compass).
   4. Glue a plastic circle on top of each tube — allow the glue to set.
   5. Arrange tubes 1, 2 & 3 over a piece of duct tape that is
       76 centimeters long.
   6. Apply a drop of glue between each tube in line with the
       duct tape.
   7. On tubes 1-3, apply drops of glue (in line with the duct
       tape) where 5 & 6 will make contact.
   8. Carefully place tubes 5 & 6 on top of tubes 1, 2 & 3.
       Position tubes 5 & 6 to be 3 centimeters higher than
       tubes 1, 2 & 3.
   9. Apply a drop of glue between tubes 5 & 6, and tightly
       wrap the duct tape around the 5-tube set — allow the
       glue to dry before moving the instrument.
   10. After the glue is completely dry, hold the instrument
       under your left arm and play with your right hand.
   11. Quickly strike/tap the drum heads (plastic circles) near
       the center to produce the best sound.
   12. Just like any instrument—Practice, Practice, Practice!

Building a 5-note Simple Guitar/Banjo
   1. Sand down your piece of wood so that you will not encounter splinters
      during your creative process. You may paint the wood for decoration—
      do so after sanding.
   2. You are now going to screw the eye hooks into the wood—two near the
      top of your piece of wood and two near the bottom. Be sure they are in
      line with each other! (You can use a nail to make it easier to get the
      hooks in).
   3. Be certain that each eye screw can turn and will not bump into its
      neighboring screw. NOTE: You do NOT want to screw the hook eyes in
      as tightly as they can be yet.
   4. Measure the length from eye hook to eye hook, in cm, and record in the
      table. This will be your l1 (length of fret 1).
   5. Use the equation ln=l1(0.9439)n-1 to figure out the various distances (in
      cm) that will correspond to frets you will need to draw on your guitar to
      produce other notes. GET THIS CHECKED BY YOUR TEACHER!



   6. Using your permanent marker and a metric ruler, measure these
      distances from your top eye hook and make a mark on your wood.
   7. Glue a wooden coffee stirrer (or craft stick) on each line.
                                             145
   8. Include the fret number (n) above the line for ease of play later.
   9. Cut 2 pieces of nylon fishing line so that they are about 11cm longer than the distance
       from top eye hook to bottom eye hook.
   10. Tie the fishing line strings tightly between each top and bottom hook.
   11. Pluck the first string and listen to the pitch that is generated. You will continue to
       tighten the top eye hook until the pitch of your guitar matches the pitch of Middle C
       (pipe 1) of your pan pipe.
   12. Once you have matched the pitch of Middle C (pipe 1) from your pan pipe on the first
       string repeat step #11 for the second string.
   13. You are now ready to play—only play ONE string at a time—the other string is a drone
       string.
   14. Add decorative elements to your guitar—maybe a colorful sound box (see diagram)?
   15. Just like any instrument—Practice, Practice, Practice!

Data Table 1- Fret calculations for Simple Guitar/Banjo

      Fret # (n)   Work: Formula : ln=l1(0.9439)n-1                               Length (cm)
      1



      2



      3



      5



      6




PLAYING YOUR INSTRUMENTS
       All of your instruments have been created
in the pentatonic scale—meaning there are 5
notes. For those of you who read music, here
are the notes those harmonic numbers match up
to. For those of you who do not read music, the
―play-by-number‖ option will be easiest.




                                            146
ANALYSIS QUESTIONS:
    PAN PIPE ANALYSIS

  1. Having longer tubes for the pan pipe _________________ the pitch of the musical
     note.

  2. Having shorter tubes for the pan pipe ________________ the pitch of the musical
     note.

  3. Length of pan pipe tubes and pitch are ______________________ related.

     XYLOPHONE ANALYSIS

  4. Having more water for the xylophone __________________ the pitch of the musical
     note.

  5. Having less water for the xylophone __________________ the pitch of the musical
     note.

  6. Amount of water and pitch are __________________________ related.

     MELODIC TUBE DRUM ANALYSIS

  7. Having longer tubes for the drum _________________ the pitch of the musical note.

  8. Having shorter tubes for the drum ________________ the pitch of the musical note.

  9. Length of drum tubes and pitch are ______________________ related.

     GUITAR/BANJO ANALYSIS

  10. Having longer length of string for the guitar _________________ the pitch of the
      musical note.

  11. Having shorter length of string for the guitar ________________ the pitch of the
      musical note.

  12. Length of string for the guitar and pitch are ______________________ related.

     GENERAL ANALYSIS

You may find this website to be a helpful resource!
     http://www.physicsclassroom.com/Class/sound/

  13. Sound waves are ______________________waves.


  14. How are pitch and frequency of a wave related?

                                            147
  15. Draw an example of a low pitch sounding wave and of a high pitch sounding wave.
LOW PITCH                                    HIGH PITCH


___________________________________             ___________________________________




   16. Do high pitch noises have more or less energy than low pitch noises? Explain how
       you know this.




   17. Middle C (#1), has a frequency of 256 Hz. Calculate its period in seconds.




   18. Would note E (#3) have a faster or slower period than Middle C (#1)? Explain how
       you know this.




   19. The diagram below shows how algebra can be used to determine the wavelength (λ)
       for each harmonic of guitar strings. Using the length of your guitar strings (in cm),
       calculate the wavelengths (in cm) for the first three harmonics. SHOW ALL WORK.



                                                                                    λ1=




                                                                                    λ2=




                                                                                    λ3=


                                             148
C Pentatonic Scale         More Music Activities




                     149
Mary Had A Little Lamb   Music Printouts




                  150
Twinkle Twinkle Little Star




            151
152
153
154
Freshman Physics        Name:______________________________________ Per:____
NOM: Light, Color and Optics                       Due Date:_________________

INTRO: To become familiar with and understand the nomenclature associated with light,
color and optics. These terms are associated with Ch 22, 23 and 24 in your textbook.

NOMENCLATURE:
Additive Color Process:




Additive Primary Colors:




Angle of Incidence:




Angle of Refraction:




CMYK Color Process:




Color:




Electromagnetic Spectrum:




Fiber Optics:




Index of Refraction




Intensity:

                                           155
Optics:




Polarizer:




Prism:




Reflection:




Refraction:




RGB Color Process:




Subtractive Color Process:




Subtractive Primary Colors:




Translucent:




Transparent:




White Light:




                              156
Freshman Physics             Name: __________________________________ Per:____
LAB: Glowsticks

PRE-LAB QUESTIONS
You are working on the light crew for the school play and you need to shine
red, blue and green lights onto the stage to create all of the colors of the
rainbow.

      1. What color do you get when you mix a green and red light?
         ______________________

      2. What color do you get when you mix a yellow and blue light?
         _____________________

      3. What color appears when you mix a red, blue and green light?
         ____________________

PROCEDURE:
1. On the transparency or glass on your lab bench, place one drop (two for blue) of each
color listed in the box. Mix the colors together with a toothpick or your fingers (careful it stains
your clothes!).

2. In the corresponding box in the table below, describe the color that was formed and write
the correct name of the color that was formed.

3. Using crayons, color in each box on this sheet with the color that you saw.


  1                RED                2               GREEN               3              BLUE




  4          RED & GREEN              5        GREEN & BLUE               6          RED & BLUE




  7         YELLOW & BLUE             8          CYAN & RED               9      MAGENTA & GREEN




                                                157
ANALYSIS QUESTIONS
  1. Circle the word that makes the sentences true.
        a. The three colors in the first row of the chart (squares 1, 2, and 3) are the
             PRIMARY       /      SECONDARY            /        COMPLEMENTARY
                    colors of LIGHT!

          b. The three colors produced in the second row (squares 4, 5, & 6) are the
             PRIMARY       /      SECONDARY            /        COMPLEMENTARY
                    colors of LIGHT!

          c. Yellow light is made up of:

              BLUE & GREEN        /        RED & GREEN          /   RED & BLUE             light

          d. CYAN         /       MAGENTA       /      YELLOW       light is made up of blue
             and green light.

          e. Magenta light is made up of:

             BLUE & GREEN         /        RED & GREEN      /       RED & BLUE             light



          f. When you mix Red, green and blue light together, the resulting color of light is
             WHITE      /      BLACK

   2. When two colors of light are added together to produce white light they are called
      complementary colors.
        a. Which row in the chart – first, second or third – show the complementary
           colors?

          b. Complete the statements:

                 i. Blue is complementary to ______________.

                 ii. Green is complementary to _____________.

                iii. Red is complementary to ______________.


   3. You have heard the expression ―yellow and blue make green‖.
         a. Is this what happen when you mixed the light colors yellow and blue?


          b. Describe a situation (remember your kindergarten days!) when yellow and blue
             combine to give green. How is this different than what you did in this lab?
                                              158
Freshman Physics         Name:_______________________________________ Per:____
ACT: Color Filters: Absorption and Transmission     Due Date:_________________

What you should know already:
You know that when light shines on something like paper or fabric, one color
is absorbed and its complement is reflected. This applies to opaque objects.

      What’s an opaque material? _________________________________

      What’s an example? _______________________________________

What happens when light shines on something transparent?
A transparent object is the opposite of an opaque object.

      What’s a transparent object? ____________________________________

      What’s an example of a transparent object? _________________________

      What does transmitted mean? ____________________________________

      What happens when different colors of light shine on a colored filter?



Using Color Filters
In the activity today, you will be looking at different colors through green, blue, and red filters.
Let’s make some predictions about what each filter will transmit and absorb.

      Green filters transmit ________ light and absorb (block) __________________ light

      Blue filters transmit _______ light and absorb (block) ____________________ light

      Red filters transmit _______ light and absorb (block) _____________________light.

How might we diagram white light shining on a green filter?




                            By the end of this activity
                    you should be able to answer this question:
                    Why do colors look different through filters?
                                                159
PROCEDURE:
Each group should have a green, red, and blue filter. Practice looking through the filters at the circles of primary and secondary colors
of light on the screen.
1. Describe the color of each number in regular white light. Write it underneath the corresponding number in the table below. The
number ―one‖ is done for you.

2. View the numbers projected on the screen through each filter. Describe the color each number looks through the different filters. If it
is the same color, write ―NC‖ for no change.

Numbers on Black Background
  Filter         1          2                       3               4               5               6               7               8
                  White .     __________      __________      __________      __________      __________      __________      __________
    Red


   Green


   Blue



Numbers on White Background
  Filter        1           2                       3               4               5               6               7               8
               __________     __________      __________      __________      __________      __________      __________          Black      .

    Red


   Green


   Blue
ANALYSIS QUESTIONS
1. Why do colors look different through colored filters than they do with just
   white light?



2. Why does a red number look black through a green filter?



3. What would a blue number look like through a….

       a. cyan filter ___________________________

       b. magenta filter ________________________

       c. yellow filter __________________________


4. What would a green number look like through a …

       a. cyan filter ____________________________

       b. magenta filter ________________________

       c. yellow filter ___________________________


5. In the following diagrams, decide what color the filter absorbs and what
   color will be transmitted.




6. In photography, you can attach a Yellow filter to your camera. How would
   this look for a landscape with lots of green grass, green leaves, and blue
   sky?




                                                                              161
More Practice: Color Filters and Transmission
For each picture, decide what colors are absorbed and what colors are
transmitted. The filter is marked with a letter indicating what color filter it
is.




                                                                                  162
Freshman Physics
      Name:________________________________________ Per:____
ACT: Paint by Numbers




        Date:_______________________




Determine the color you would see based on the description.

   #                  Description                             Color
   1                Reflects Red Light

   2                Absorbs Blue Light

   3              Absorbs Magenta Light

   4              Reflects Magenta Light

   5               Blocked by Red Filter

   6         Red, Green & ____ Primary Color

   7          ___ + Magenta + Cyan = Black

   8              White light – green light

   9                Reflects Blue light

   10              Absorbs Green Light

   11                 Reflects all light




                                                                      163
 12          Reflects Yellow Light

 13       Blocked by Magenta Filter

 14    Yellow + Magenta + _=Secondary

 15     __ + Blue + Red = White light

 16         Blocked by Cyan Filter

 17          Reflects Cyan Light

 18            Absorbs All Light

 19          Absorbs Cyan Light

 20          Reflects Green Light

 21         Blocked by Blue Filter

 22        Blocked by Yellow Filter

 23         Absorbs Yellow Light

 24           Absorbs Red Light

 25        Blocked By Green Filter

 26      White Light – Yellow Light =

 27       Passes Through red filter

 28       Passes through blue filter

 29       Passes through green filter

 30      Passes through yellow filter

 31        Pass through cyan filter

32 –
Make
your
own!




                                        164
Using C, M, and Y (the subtractive primary colors of paint), how would
make the following paints:

 Red:                              Black:                         White:


 Blue:                             Yellow:                        Cyan:


Green:                            Magenta:




                                                                         165
166
COLOR REVIEW OF EVERYTHING!

   1. When white light shines on a fabric or paper that has pigment, some
      light is ____________ and some light is ______________. The color
      we see is the light that is ___________________.

   2. Pure ____________ absorb one color of light and reflect its ________________
      color.
          a. Blue paints (or pigments) absorb ______________ and reflect blue.
          b. Green paints absorb ____________ and reflect green.
          c. Red paints absorb ______________ and reflect red.
          d. Magenta paints absorb ____________ and reflect magenta (red + blue).
          e. Cyan paints absorb ______________ and reflect cyan (blue + green)
          f. Yellow paints absorb ___________ and reflect yellow.


Fill in the blanks. (Some may require more than one color!)

1. Red, blue, and green light are the primary colors of ____________.

2. Cyan, magenta, and yellow are the primary colors of ___________.

3. Red light + blue light = _________________.

4. White light - red light = _________________.

5. White light - blue light = ________________.

6. Green light + blue light =________________.

7. Green light + blue light + red light = _________________.

8. Magenta light + cyan light = _____________________.

9. Magenta light + green light = _____________________.

10. A piece of cyan paper illuminated with red light will look __________________.

11. A piece of magenta paper illuminated with red light will look.________________.

12. A piece of blue paper illuminated with red light will look ___________________.

13. Yellow paint absorbs _________________________light and reflects yellow.




                                                                                      167
14. A magenta filter absorbs_______________________light but lets _______ and
________ pass through.

15. A cyan filter allows ________ and _________ light to pass through it but absorbs
____________.

16. A piece of blue paper illuminated with yellow light will look _______________.

17. A cyan filter placed over a magenta filter will allow _________________ light to
pass through it.

18. A red filter placed over a magenta filter will allow __________________ light to pass
through it.

19. A red filter placed over a cyan filter will allow ________________________light to
pass through it.

20. In order to get a true green color, an artist would mix___________and ___________
paints.

21. In order to get a true red color, an artist would mix____________ and ___________
paints.

22. Magenta paint mixed with yellow and cyan paints produces___________________




                                                                                       168

								
To top