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Team Members: Louie McTall Paul Muskopf Tom Noble Shane Reilly Ben Rissing Paul Tucker Former Team Members: Gavin Duncan Gavin Jackson Charlie Safley Day 1: Science vs. Engineering and Catapult Introduction Overview: The students will learn the difference between scientists and engineers. They will also learn about the engineering design process and how it differs from scientific experimentation. A basic introduction to catapults as well as catapult history will be presented to familiarize the students with our project. Teacher Prep Time: 20 min Make copies of Science vs. Engineering Worksheet (W1.1) and Catapult History Handout (H1.1) for all students Prepare the demonstration video o Get TV and VCR Prepare the catapult demonstration o Read Teacher Manual to understand catapult operation Objectives: Students will be able to understand the engineering design process Students will compare and contrast this process with scientific experimentation Teach students basic catapult history and build student interest in catapults Teaching Standards: Virginia SOLs: PS.1 The student will plan and conduct investigations in which n) an understanding of the nature of science is developed and reinforced Massachusetts Science and Technology / Engineering Curriculum Framework: 2.1: Identify and explain the steps of the engineering design process, i.e., identify the need or problem, research the problem, develop possible solutions, select the best possible solution(s), construct a prototype, test and evaluate, communicate the solution(s), and redesign. ITEA’s Standards for Technological Literacy: Standard 7: Students will develop an understanding of the influence of technology on history. Standard 9: Students will develop an understanding of engineering design. Materials: Science vs. Engineering Worksheet (W1) Catapult History Handout (H1) Operational ETK Catapult Demonstration video Description of Class: Science v. Engineering (25 min) 1. T. distributes both worksheet and handout to students. Students will fill in answers as the class progresses 2. T. asks students what they know about scientific experimentation. T. has students write steps on board. 3. T. discusses how scientists use scientific experimentation to explore the world around them Scientist will research and experiment to test a general theory or question and see if it is true or false. 4. T. asks students to individually write 5 words that describe a scientist. T. writes students words on board as they call them out. T. discusses words with class 5. T. asks students “Using what you know about scientific experimentation, what do you think the engineering design process is?” To start them off, T. will draw the first block of the engineering process on the board and say “Instead of starting with a question, engineers start with a design problem.” With student aid, T. completes the engineering design process on the board. 6. T. asks students to individually write 5 words that describe an engineer. T. writes students words on board as they call them out. T. discusses words with class (similarities and differences between the words used for the scientist and the engineer) 7. T. sums up the differences between science and engineering (reference Teacher Manual) Catapult Introduction (25 min) 8. T. shows demonstration video 9. T. uses video to transition into a brief outline of what the catapult ETK will cover and of the design challenge. 10. T. shows the students the catapult they will be working with and gives a brief demonstration of how it works. 11. T. leads discussion on catapult history using the History Handout (H1.1) W1.1: Science vs. Engineering Worksheet Scientific Experimentation The Engineering Design Process 5 Words that Describe a Scientist 5 Words that Describe an Engineer 1. 1. 2. 2. 3. 3. 4. 4. 5. 5. W1.1: Science vs. Engineering Worksheet (teacher’s copy) Scientific Experimentation The Engineering Design Process Question Identify Problem Form Brainstorm Hypothesis Ideas Experiment Develop Design Revise Design Collect and Test Analyze Data Design Form Develop Conclusion Final Report 5 Words that Describe a Scientist 5 Words that Describe an Engineer 1. 1. 2. 2. 3. 3. 4. 4. 5. 5. H1.1: Catapult History Handout Catapults Catapults were the first form of field artillery used during battles by the Greeks. They were used as "siege" machines. The word "siege" means the surrounding and blockading of a town or fortress by an army trying to capture it. The word Catapult comes from the two Greek words "kata" and "pultos". "Kata" means downward and "pultos" refers to a small circular shield carried in battle. Katapultos was then taken to mean "shield piercer". The Ballista The first catapults used by the Greeks were based on the bow and arrow but of a much larger size. The "Ballista" was the name given to the first Greek Catapult. It fired spears instead of arrows and its bow worked very differently from a normal bow. The Ballista worked like the small wooden propeller and rubber band air planes that children play with today. Top view of a Ballista. A Ballista being set into firing position. The Trebuchet It is believed that the Trebuchet originated in China around 300 BC. Its use in Western Europe can be traced to the crusades of the 12th century. There were two types of trebuchets. 1. The traction trebuchet used people as a power source. The people would haul down the shorter end of the beam which flipped up the longer end. A sling was attached to the longer end of the beam. As the longer end reached its apex, the sling opened releasing a large stone or other object. The traction trebuchet was good for throwing incendiaries and heads. Traction Trebuchet about to be fired. 2. The Counterweight Trebuchet replaced the people power with a weight on the short end. The longer end was pulled down, lifting the weighted end. Upon release, the weight pull down the shorter end down and the longer end swung up. A stone was released from the sling at the apex of the swing. Counterweight Trebuchet prepared to fire. Day 2: Energy Overview: Students will gain an appreciation of energy principles, including kinetic and potential energy. They will also examine the basic equations governing energy. The teacher will lead a discussion of the Law of Conservation of Energy and the SI unit system. Students will complete an activity on the subjects of spring constants and potential energy. Teacher Prep Time: 20 min Make copies of Energy Worksheet (W2.1) and Spring Constant Worksheet (W2.2) for all students Obtain supplies for Spring Constant Experiment o A spring scale for each group o A ruler for each group o Rubber bands of different thickness and sizes for each group Objectives: Students will be able to understand the both kinetic and potential forms of energy Students will become familiar with the equations governing kinetic and potential energy Students will learn about the Law of Conservation of Energy Students will be able to identify SI units pertaining to the ETK Students will learn how potential and kinetic energy relates to springs and rubber bands. Teaching Standards: Virginia SOLs: PS.1 The student will plan and conduct investigations in which b) length, mass, volume, density, temperature, weight, and force are accurately measured and reported using the International System of Units; c) conversions are made among metric units applying appropriate prefixes; d) triple beam and electronic balances, thermometers, metric rules, graduated cylinders, and spring scales are used to gather data; PS.5 The student will investigate and understand changes in matter and the relationship of these changes to the Law of Conservation of Matter and Energy. Key concepts include a) physical changes. PS.6 The student will investigate and understand states and forms of energy and how energy is transferred and transformed. Key concepts include a) potential and kinetic energy; b) mechanical, chemical, and electrical energy; and c) heat, light, and sound. PS.10 The student will investigate and understand scientific principles and technological applications of work, force, and motion. Key concepts include c) work, force, mechanical advantage, efficiency, and power Math 8.14 The student will a) describe and represent relations and functions, using tables, graphs, and rules Math 8.17 The student will create and solve problems, using proportions, formulas, and functions. Math 8.18 The student will use the following algebraic terms appropriately: domain, range, independent variable, and dependent variable. Materials: Every student receives Energy and Spring Constant Worksheets Each group needs: o Rubber bands A, B, C, and D o Ruler o Spring Scale Description of Class: Introduction to Energy (25 min) Note: Students will use the information in 1, 2, 3, and 4 to complete Energy Worksheet (W2.1) 1. T. passes out energy worksheet. Students fill in answers as teacher covers concepts. 2. Forms of Energy: T. states that all forms of energy can be put into one of two main categories. T. writes the two categories on board: Potential & Kinetic. T. has students brainstorm examples of Potential and Kinetic energy. 3. T. discusses Law of conservation of energy: T. states that energy can NOT be created or destroyed, it can only change forms. о Example: T. lifts a book up into the air and says that it now has potential energy. If T. drops the book the potential energy will be converted into kinetic energy as the book falls. When the book hits the floor, the kinetic energy of the book moving will be converted into sound and heat. T. drops the book. 4. Equations that Govern Energy: T. states that the Potential Energy related to the height of an object is known as gravitational potential energy. T. writes the equation for gravitational potential energy on the board and describes each term. о PEgravity = Mass x gravity x height о To demonstrate T. gets book from before and drops on floor from a height of approximately 6 inches. Then T. drops book on floor from a height of several feet above. T. explains that the book will go faster and make more noise at impact as the height it is dropped from increases. This is because its potential energy increases as height increases. T. talks about springs and how they are one way to store potential energy. T. writes states that Hookes Law allows us to calculate the amount of potential energy contained in a spring, writes the equation on the board, and describes each term. о Hookes Law: K = spring constant о PEspring = ½ K x (Length2 – Length1)2 о To demonstrate T. shoots a rubber band at the board, but only pulls the rubber band back an inch or two. T. then shoots a rubber band at the board, pulling the rubber band back as far as possible. T. explains that the rubber band goes faster and farther as the length you pull it back increases. This is because its potential energy increases as length increases. T. states that an object in motion has kinetic energy. T. writes the equation for kinetic energy of motion on the board and describes each term. о KEmotion = ½ mass x velocity2 о T. explains the transformation of energy in the two previous cases (book and rubber band). When the book is dropped, the PE becomes KE as it falls. Because of the Law of Conservation of Energy, no new energy is created. PE is converted to KE! When the rubber band is shot at the board, the PE becomes KE in the same manner. 5. Spring Constant Activity (25 min) 6. T. divides students into groups. 7. T. passes out spring constant worksheet and materials to each group. 8. T. reminds students and writes on board the conversion between centimeters and meters. 9. T. goes around and makes sure that each group of students completes the activity. See picture below for a more detailed view of the experiment setup It is easier to hold the spring stationary if a bolt is passed through one end of the spring. Measure displacement from the spring scale/spring connection. Make sure to position the spring scale so that you read Newtons. 10. If class period ends before students can complete Activity 2, T. assigns it for homework. W2.1: Energy Worksheet (Teacher’s copy) There are two main categories of energy, potential and kinetic. Write at least 3 examples of each: Potential (Stored Energy) Kinetic (Objects in Motion) 1. Holding Object in Air 1. Moving Car 2. Stretched Rubber band/Spring 2. Baseball after being hit 3. Roller Coaster at top of hill 3. Roller Coast at bottom of hill As the teacher goes over the following material, fill in the empty spaces: The Law of Conservation of Energy says that energy cannot be created or destroyed. There are several types of energy (you listed six above). We will talk about two specific types of potential energy and one specific type of kinetic energy. Potential Energy related to the height of an object is called Gravitational Potential Energy. The equation used to calculate the amount of this energy follows: PEgravity = Mass x Gravity x Height Springs are one device used to store potential energy. The equation used to calculate the amount of this energy follows: PEspring = ½ K x (Length2 – Length1)2 In this equation K = Spring Constant Moving objects have Kinetic Energy of Motion. The equation used to calculate the amount of this energy follows: KEmotion = ½ Mass x Velocity2 W2.1: Energy Worksheet There are two main categories of energy, potential and kinetic. Write at least 3 examples of each: Potential Kinetic 1. 1. 2. 2. 3. 3. As the teacher goes over the following material, fill in the empty spaces: The Law of Conservation of Energy says that energy cannot be created or destroyed. There are several types of energy (you listed six above). We will talk about two specific types of potential energy and one specific type of kinetic energy. Potential Energy related to the height of an object is called Gravitational Potential Energy. The equation used to calculate the amount of this energy follows: PEgravity = Mass x Gravity x Height Springs are one device used to store potential energy. The equation used to calculate the amount of this energy follows: PEspring = ½ K x (Length2 – Length1)2 In this equation K = Spring Constant Moving objects have Kinetic Energy of Motion. The equation used to calculate the amount of this energy follows: KEmotion = ½ Mass x Velocity2 W2.2: Spring Constant Worksheet Activity 1: We will determine the spring constants (K) of different springs. Procedure: 1) Attach one end of the spring to the spring scale and the Pull this other end around a bolt. Position the ruler so that 0 is at direction the spring scale – spring connection. 2) Stretch the spring a little bit to get rid of slack. RULER 3) Write down length (Length 1) and reading on the scale (Force 1) in the chart below. Spring scale 4) Stretch spring 5 more centimeters and record length (Length 2) and spring scale reading (Force 2) (Remember 100 centimeters = 1 meter). 5) Repeat procedure for each of the different springs (B, C, and D). Spring 6) Calculate spring constant (K) using the rearranged equation from the energy worksheet: K = (Force 2 – Force 1)___ Hold this end (Length 2 - Length 1) Spring Length 1 (m) Force 1 (N) Length 2 (m) Force 2 (N) K (N/m) A B C D Activity 2: We will determine how much potential energy is stored in each spring if we stretch it 15 cm? 30 cm? Hints: Don’t forget about the units! 1 joule = 1 N m Use the appropriate K value from the chart you just completed PEspring = ½ K x (Length 2 – Length 1)2 Spring K (N/m) PE at (Length 2 – Length 1) = PE at (Length 2 – Length 1) = (from above) 15 cm (0.15 m) 30 cm (0.3 m) A B C D Day 3: Simple Machine (Levers) & Projectile Motion Overview: Students will gain knowledge of simple machines, specifically levers and how they apply to catapults. Students will gain an interactive, conceptual knowledge of projectile motion. Teacher Prep Time: 20 min T. must set up three catapults for the lever demonstration. The fulcrum of each catapult arm will be at a different point, one in the middle, one on the extreme right, and one on the extreme left. Each lever has a weight on the right end (see diagrams below). T. make enough copies of Simple Machine Handout and Lever Worksheet for the entire class Objectives: Students will recognize the 6 types of simple machines. Students will understand the 3 classes of levers. Students will understand the relationship f1d1 = f2 d2 Students will see real life applications of projectile motion. Students will gain experience with equations and substitution. Teaching Standards: Virginia SOLs: PS.10 The student will investigate and understand scientific principles and technological applications of work, force, and motion. Key concepts include a) speed, velocity, and acceleration; c) work, force, mechanical advantage, efficiency, and power; and d) applications (simple machines, compound machines, powered vehicles, rockets, and restraining devices). Math 8.17 The student will create and solve problems, using proportions, formulas, and functions. Math 8.18 The student will use the following algebraic terms appropriately: domain, range, independent variable, and dependent variable. Materials: Simple Machine Worksheet (W3.1) for each student Levers Worksheet (W3.2) for each student Styrofoam (5” diameter) ball 3 Catapults and 3 equal weights 1 fully prepared Catapult Description of Class: Simple machines and Levers (25 min) 1. T. asks students what they think simple machines are 2. T. explains that simple machines are tools used to make work easier. 3. T. describes the 6 types: inclined plane, wedge, screw, lever, wheel and axle, pulley. Students fill in worksheet (W3.1) as teacher goes over material. 4. T. talks about how simple machines are all around us. T. asks students to point out simple machines just within the classroom. Then T. asks students to identify simple machines they use at home every day. 5. T. moves discussion specifically to levers T. goes over the important terms “Load, pivot, and effort” describing each T. says there are three classes of levers: Class I, Class II, Class III The classes are based upon where the pivot point is relative to the load and effort Load 20 lbs Effort Fulcrum See Teacher’s Copy of W3.1 for explanation of lever classes о Note: “Nutcracker” in the worksheet is not the soldier-type cracker, but the one pictured below 6. T. then says we will be using levers with the catapults 7. T. does lever demonstration using catapult pieces and weights. T. selects student to help with demonstration T. and student go to catapult with fulcrum at point A and weight on one end. Student pushes on side of lever opposite the weight, raising the weight. A B C Student then moves catapult with fulcrum at point B and repeats the process. A B C Student moves to catapult with fulcrum at point C and repeats process. A B C Student then reports to class which point was easiest and hardest to lift the weight. (it should be Point A) 8. T. then explains why it is easier to raise weight at one point than another using the f1 d1 = f2d2 relationship. T. works out example problem from Lever worksheet on the board using the equation and draws a diagram to help students understand. Projectile Motion (25 min) 9. T. begins with some review questions: What is velocity? о How fast something is moving and in what direction What is acceleration? о How quickly an object’s velocity is changing о Good example would be to talk about riding in a car At a stop you have zero velocity and acceleration You start moving (accelerating) and your velocity increases until you hit the speed limit, acceleration goes to zero because velocity is staying the same. Same principle with slowing down and stopping. 10. T. introduces gravity as a type of acceleration 11. T. does Gravity demonstration T. Drops Styrofoam ball, asks students why the ball fell о Fell because of gravity T. describes how gravity affects all objects equally о Drops two objects, one light, one heavy, simultaneously о Two objects hit ground at same time, proving the point 12. T. introduces horizontal and vertical components of velocity T. stands still in front of the blackboard tossing ball up and down. T. discusses vertical velocity with students о By throwing the ball you are giving it a velocity upward о Because gravity is a type of acceleration, it caused the ball to come back down. о Draw up and down motion of ball on board T. walks across front of backboard with ball in hand. о T. discusses with students how walking with the ball gives it horizontal velocity о Draw horizontal motion of ball on board. T. then asks “What happens if I combine the two by walking while throwing the ball up?” о The board should have two arrows on it, as such: T. then walks and tosses the ball at the same time. о Ball moves in an arc, draw arc on board: T. then asks, “What happens if I walk faster or slower?” о The ball will take a different path о Draw faster or slower arcs on the board over the original arc: о Tomorrow we’re going to talk about adjusting these two variables (horizontal and vertical velocity) to make the best catapult. W3.1: Simple Machines Worksheet (Teacher Copy) Fill in the blanks as the teacher goes through the information. Identify the Simple Machine by writing its name below the picture Simple machines are use to make work easier There are six basic types of simple machines, they are… Inclined Plane Lever Wedge Pulley Wheel and Axle Screw Simple machines can be found in the world all around us. List some of the simple machines you found in the classroom… Light switch (lever), Bottom of sink (Inclined plane), Handicap ramp (Inclined Plane), Stapler (Lever), Staple (wedge), Push pin (wedge), Cap to soda bottle (screw), Knobs on sinks (screw), Rolling Chair (wheel and axle), Scissors (lever) There are also simple machines that we use every day at home, list some of those below… Compound bow (Pulley), Broom (lever), Car wheels (wheel and axle), Bikes (wheel and axle, lever), Stairs (inclined plane), Salad tongs (lever), Corkscrew (screw), Knife (wedge) The simple machine we will use with the catapults is the Lever There are three classifications of levers. The classes are based upon where the pivot is relative to the load and effort. In the picture below, label the load, pivot, and effort. Effort Fulcrum Load Write short description of each class below… First Class: The pivot is between the effort and load Second Class: The load is between the pivot and effort Third Class: The effort is between the pivot and load W3.1: Simple Machines Worksheet Fill in the blanks as the teacher goes through the information. Identify the Simple Machine by writing its name below the picture Simple machines are use to There are six basic types of simple machines, they are… Simple machines can be found in the world all around us. List some of the simple machines you found in the classroom… There are also simple machines that we use every day at home, list some of those below… The simple machine we will use with the catapults is the There are classifications of levers. The classes are based upon where the pivot is relative to the load and effort. In the picture below, label the load, pivot, and effort. Write short description of each class below… First Class: Second Class: Third Class: W3.2: Levers Worksheet Object Class Scissors Wheelbarrow Seesaw Tongs Fishing rod Nutcracker Use f1d1 = f2d2 f2 f1 d1 d2 _______________________________ Ex. f1 = 3 f2 = ? d1 = 4 d2 = 1 f1d1 = f2d2 (3) x (4) = (f2) x (1) 12 / 1 = (f2) 12 = f2 1. f1 = 1 f2 = 3 d1 = 2 d2 =___ 2. f1 = 2 f2 = 2 d1 = ___ d2 = 3 3. f1 = 4 f2 =___ d1 = 3 d2 = 2.5 4. f1 =___ f2 = 3.5 d1 = 1.5 d2 = 2 W3.2: Levers Worksheet (Teacher Copy) Object Class Scissors 1 Wheelbarrow 2 Seesaw 1 Tongs 3 Fishing rod 3 Nutcracker 2 Use f1d1 = f2d2 f2 f1 d1 d2 _______________________________ Ex. f1 = 3 f2 = ? d1 = 4 d2 = 1 f1d1 = f2d2 (3) x (4) = (f2) x (1) 12 / 1 = (f2) 12 = f2 1. f1 = 1 f2 = 3 d1 = 2 d2 = 0.67 2. f1 = 2 f2 = 2 d1 = 3 d2 = 3 3. f1 = 4 f2 = 4.8 d1 = 3 d2 = 2.5 4. f1 = 4.67 f2 = 3.5 d1 = 1.5 d2 = 2 Day 4: Introduction to Competition and Design Parameters Overview: Students will be introduced to the design competition, will conduct an experiment, and will begin design of their team’s catapult. Teacher Prep Time: 20 min Objectives: Students will investigate how angels affect horizontal and vertical velocity Students will conduct scientific experiment using catapults Students will begin to exercise the engineering design process. Materials: Catapult for each team Rubber bands, springs, and nuts/bolts Reusable ammunition for each group (for multiple launches) Experiment worksheet (W 5.1) Design Competition Worksheet (W 5.2) Measuring tape for each “Launch Station” Description of Class: Experiment (15 min) 1. T. distributes experiment worksheet (W 5.1) 2. T. begins experiment In the experiment, the catapult will be launched with the same ammunition and rubber band, but from 5 different release angles Firing distance will be measured at each angle using a measuring tape. Height is estimated. Students will put distance and height into chart on worksheet and plot the resulting points on the given graph. Suggest T. involves students as much as possible. The experiment is not exact. T. should run through the experiment beforehand and practice stretching the spring an equal distance on each launch. Design Competition Introduction (35 min) 3. T. hands out design competition worksheet (W 5.2), rubber bands, springs, nuts/bolts and a catapult to each group 4. T. explains rules of design process T. establishes rule that you cannot launch anything if you are not at the teacher’s launch station wearing safety goggles T. goes over what design variables you can and cannot change T. sets up “Launch Station” о Each team must design for a minimum of 10 minutes before they can go to the launch station о The launch station is only open to one team at a time and each team only gets one shot when they are there о After firing, the team returns to their table and improves/changes their design. W4.1: Experiment Worksheet In this experiment you will launch the catapult from five different angles. After each shot is fired, measure and record the horizontal and vertical distance traveled. Angle Horizontal Distance Vertical Height 15 30 45 60 75 Now Graph the data you’ve collected: Angle vs. Distance 20 Distance (feet) 15 10 5 0 0 15 30 45 60 75 90 Angle (degrees) Angle vs. Height 10 8 Height (feet) 6 4 2 0 0 15 30 45 60 75 90 Angle (degrees) W4.1: Experiment Worksheet (teacher’s copy) In this experiment you will launch the catapult from five different angles. After each shot is fired, measure and record the horizontal and vertical distance traveled. (The values here are approximations, but the graphs should have the same general shape) Angle (and position of stop bar in relation to pivot, see pictures on next page for more detail) Horizontal Vertical 15 (down 1 over 2) 6 7 30 (down 2 over 2) 10 6 45 (down 4 over 3) 15 5 60 (down 3 over 1) 10 4 75 (down 2 over 0) 6 3 Now Graph the data you’ve collected: Angle vs. Distance 20 Distance (feet) 15 10 5 0 0 15 30 45 60 75 90 Angle (degrees) Angle vs. Height 10 8 Height (feet) 6 4 2 0 0 15 30 45 60 75 90 Angle (degrees) Pictures of locations of pivot and stop for experiment: The down __ over ___ directions are for the location of the stop bar in relation to the pivot. 15 degrees: 30 degrees: Down 1, Over 2 Down 2, Over 2 45 degrees: 60 degrees: Down 4, Over 3 Down 3, Over 1 75 degrees: Down 2, Over 0 W 5.2: Design Competition Worksheet Use this worksheet to keep a record of your design process as you modify and improve your catapult. Each time you test your catapult, quickly label the catapult’s layout and make some notes regarding its performance. If you run out of room on this sheet ask your teacher for another. Example: Design 1: Design worked just ok ______________________ Ball traveled 15 feet ______________________ Design 2: Design 3: __________________________ __________________________ __________________________ __________________________ Design 4: Design 5: __________________________ __________________________ __________________________ __________________________ Design 6: Design 7: __________________________ __________________________ __________________________ __________________________ Day 5: Competition and Wrap-up Overview: Students will complete their design and compete against one another. T. leads wrap-up conversation at end Teacher Prep Time: 20 min Objectives: Students will put their engineering design into practical application Students will have fun and learn Teaching Standards: Materials: Catapult for each team Rubber bands, springs, and nuts/bolts Reusable ammunition for each group (for multiple launches) Measuring tape for each “Launch Station” Cardboard “Town” The student’s W5.2 which contains their design history Description of Class: Finalize Design (10 min) 1. Students finalize their design based upon parameters as discussed in day 4 2. Students decide on team name Competition (35 min) 3. T. draws team names out of hat to decide who goes first, second, third, etc… 4. Each team rotates through trying for accuracy first (Hitting fortress wall) 5. After completion of accuracy competition, teams get 5 min to adjust catapults for distance competition 6. Each team rotates through distance competition 7. T. scores final results and announces winner Wrap Up (5 min) 8. T. collects supplies and left over ammunition from students 9. T. asks students what they’ve learned from the week 10. What was the most fun part? What was the worst part? What do they still not understand? Teacher Manual / Supplement to Experiments and Examples Simple Machines: 1. Inclined Plane – A sloped surface used to move objects up a certain distance. Allows one to use less force over a longer distance instead of a large force over a shorter distance. 2. Lever – A long board or rod that pivots about a point known as the fulcrum. On one side of the fulcrum is the load while the effort, or force, is placed at the opposing end. By adjusting the fulcrum relative to the load and effort, it is possible to minimize the force needed to lift the load. 3. Wedge – Two inclined planes joined together, back to back. A wedge is used to split objects, such as wood. 4. Pulley – A grooved wheel, typically with a rope around it. By pulling down on the rope at one end, a person can lift an object at the other end. If a series of pulleys is used, the force required to lift a load may be significantly reduced. 5. Wheel and Axle – A wheel and axle consists of a cylindrical rod through the center of the wheel. When the axle is turned, the wheel turns a greater distance, which is how you get your mechanical advantage. Also, turning the axle requires less force over a longer distance than turning the wheel alone. 6. Screw – An inclined plane wrapped around a shaft or cylinder. The screw gives mechanical advantage by raising or lowering objects as it is turned. The force required to turn the screw is less than that of lifting the object directly (think of a car jack). (Information based upon: http://edheads.org/activities/simple-machines/sm-glossary.htm) Levers: Force-Distance Relationship f1d1 = f2d2 f1 = force #1 Doesn’t matter which side is #1 or which side is #2, as long as f1 and d1 are on the same side. d1 = distance #1 f2 and d2 are just like f1 and d1, but on the other side The relationship essentially states that for a given weight (f1) at a specified distance from the fulcrum (d1), you can apply a corresponding force (f2) at a certain distance (d2) such that the lever is balanced.
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