# GCSE physics whole course ammended to P2 2010

Document Sample

```					AQA GCSE PHYSICS ►

Use arrow keys to advance within a slide
Cost   Charge
Mains                        Control
Graphs
Energy                                                      Acceleration
Voltage                                                                      Friction
Electricity
Structure                                                              Forces                   Moments

Induction                                           PHYSICS                                            Circular

Waves                     Characteristics
Electromagnetism                Energy
Electromagnetic
Work                                                                                Optical
Space                                Sound
Resources
Efficiency                                               Seismic
Thermal                          Tectonic
Universe   Solar

Electricity ► Idea map

1                Electron
Atom

Proton   Neutron

Moving               Stationary

Current               Charge

Voltage           Energy          Mains        Control

Cost
Electricity ► Voltage ► Idea map

1.1               Energy              Electrons

causes...
Voltage                         Current

Circuit

Series        Parallel              Components

Ammeter          Voltmeter      Thermistor         LDR
Electricity ► Voltage ► Energy and Electrons

•   Electricity is fundamentally about 2 things…

•   Energy                       •   Electrons
•   Ability to do                •   Tiny particle
•   Invisible                    •   Carry charge
•   Carry Energy
•   Effectively Invisible
Electricity ► Voltage ► Current

•    Electric Current
•    Current
•    Flow of charge         Mean the same
•    Electricity
•    Moving Electrons
•    Symbol I

Small Current         Large Current
Electricity ► Voltage ► Amps

A

•   The current flowing through a component in a circuit is measured in amperes (A).

•   An ammeter is connected in series with the component.

•   1 Amp = 6 billion billion electrons per second
Electricity ► Voltage ► Voltage Idea

•     Energy per electron
•     Voltage                        Mean the same
•     Potential Energy
•     Potential
•     Symbol V

Low Voltage                High Voltage

Low energy Electron          High energy Electron
Electricity ► Voltage ► Potential Difference

•   Potential Energy Difference
Mean the same        between 2 points on a wire
•   Potential Difference
•   P.D.
•   Difference in Voltage
•
Energy

Voltage across
Electricity ► Voltage ► Voltmeter

V
4 Volts

The p.d. across a component in a circuit is measured in volts (V)

A voltmeter connected across (in parallel with) the component.
Electricity ► Voltage ► Relationship Concept

• The next four slides make essentially the same point about the
relationship between current and voltage…

•   Relationship
•   Proportional
•   Connection
•   One can be worked out from the other
Mean the same
•   One causes a change in the other
•   A formula allows us to calculate a value
•   Dependent
Electricity ► Voltage ► Voltage needed

• A current will flow through an electrical component (or device)…

• Only if there is a voltage or potential difference (p.d.) across its ends.
Electricity ► Voltage ► More voltage, more current

• The bigger the potential difference across a component…

• The bigger the current that flows through it.
Electricity ► Voltage ► Graphing Relationship

Current

Proportional : As one value increases
so does a second value

Voltage

•   Current-voltage graphs are used to show how the…

•   Current through a component varies with the voltage across it.
Electricity ► Voltage ► V = I R

• The current through a resistor (at constant temperature) is
proportional to the voltage across the resistor.

Voltage      =     Current        x          Resistance
V         =          I         x              R
10 Volts     =     2 Amps         x           5 Ohms
Electricity ► Voltage ► Series Circuit

3A      12 V

3A
3A
6V            6V
2Ω           2Ω

4Ω

•   When components are connected in series:

•   Their total resistance is the sum of their separate resistances.
•   The same current flows through each component.
•   The total potential difference of the supply is shared between them
Electricity ► Voltage ► Parallel Circuit

12 V
3A

3A
12 V          2A

12 V

1A
•   When components are connected in parallel:

•   The current in the branches equals that leaving the battery
•   The current may vary from branch to branch
•   The total potential difference of the supply is same for each branch
Electricity ► Voltage ► Filament Bulb

Resistance

Temperature

• The resistance of a filament lamp increases…
• As the temperature of the filament increases.
Electricity ► Voltage ► Diode

CURRENT
normal flow

VOLTAGE

no flow

• The current through a diode flows in one direction only.

• The diode has a very high resistance in the reverse direction.
Electricity ► Voltage ► Light Dependent Resistor

1000 Ω                          10 Ω

•   Could be called “darkness dependent resistor”
•   The resistance of a light dependent resistor decreases…
•   As the light intensity increases.
•   It resists when it is dark…
Electricity ► Voltage ► Thermistor

1000 Ω                    10 Ω

•   A “coldness dependent resistor”
•   The resistance of a thermistor decreases…
•   As the temperature increases.
•   Resists when it is cold
Electricity ► Voltage ► Symbols

Cell     Switch (open)
Battery                                           Switch (closed)

Variable resistor                                           L.D.R

Fuse                                                       Diode

A

Resistor
V              Ammeter
Lamp
Thermistor
Voltmeter
Electricity ► Energy ► Ideas map

1.2                 deliver…
Electrons

in a certain…
Coulomb

Energy (J)         Time (s)

to give us…
Power                        Watt (J per s)

Voltage       x    Current
Electricity ► Energy ► Electrons carries energy

10 J                                 £20

•   This is an electron
•   It collects energy at the battery…
•   Travels around a circuit…
•   And delivers it to a component
Electricity ► Energy ► Electrons deliver Energy

30 J                                          £30

Bank

Shop         Shop

20 J          10 J                          £20          £10

• As an electric current flows through a circuit, energy is transferred

• The energy is transferred from the battery or power supply…

•   …to the components in the electrical circuit.
Electricity ► Energy ► Heat from a wire

•   When Charge flows through a resistor, electrical energy is
transferred as heat.
Electricity ► Energy ► Energy per Time
Electricity ► Energy ► Power

• Power is energy transferred per second
• Power is measured in Joules per Second known as a Watt
10 J
10 J
• 1 Watt = 1 J of energy in 1s

Power      =    Current     x     Potential Difference
P        =       I        x              V
10 Watts    =     2 Amp      x            5 Volt
Electricity ► Energy ► Coulomb

• Seconds are inconveniently small to measure the age of a person.
• We use a word which means 31,536,000 seconds.
• The word is year.

• Electrons are inconveniently small to measure everyday numbers of electrons.
• We use a word which means 6,000,000,000,000,000,000 electrons
• The word is Coulomb.

1km                   1km

1km                   1km

1km                    1km

2 cubic kilometres contain about 6 billion billion grains of salt
Electricity ► Energy ► E = VQ

• The higher the voltage of a supply…
• the greater the amount of energy transferred for…
• a given amount of charge which flows.

Energy        =   Potential Difference   x       Charge
E          =            V             x          Q
10 Joules      =         5 Volts          x      2 Coulombs
Electricity ► Energy ► Q = I t

3 Coulombs / Sec             …For 5 Seconds…
(3 Amps)

Equals 15 Coulombs

Charge      =       Current      x          Time
Q        =         I          x            t
15 Coulombs    =       3 Amps       x       5 seconds
Electricity ► Energy ► Table of 7 key ideas

DESCRIPTION         NAME         SYMBOL   UNIT

Ability to do       Energy       E        Joule (J)

Electrons           Charge       Q        Coulomb (C)

Change              Time         t        Second (s)

Charge per Time     Current      I        Amp (A)

Energy per Charge   Voltage      V        Volt (V)

Energy per Time     Power        P        Watt (W)

Obstacle            Resistance   R        Ohm (Ώ)
Electricity ► Energy ► 7 ideas connected

R

1.V=IR
V            I
2. E = V Q

3. E = P t
E           Q          t

4. Q = I T

5. P = I V
P
Electricity ► Mains ► Ideas map

1.3              Direct
Types of Current

Alternating

Mains

Plug                                  Safety

Live     Neutral        Earth             Fuse        Circuit Breaker
Electricity ► Mains ► Mains voltage

• The UK mains supply is about 230 volts.

• Mains can kill if it is not used safely.
Electricity ► Mains ► Plug

Earth pin
Copper Core

Plastic Layer                                                                Fuse

Live pin

Plastic Case

Neutral Pin                                Cable grip

• Brass Pins and Copper Wires are conductors, plastic is an insulator
Electricity ► Mains ► Alternating Current

• An alternating current (a.c.) is one which is constantly changing
direction.

• Mains is an a.c. supply.

• In the UK it has a frequency of 50 cycles per second or 50 hertz
(Hz) which means that it changes direction and back again 50
times each second.
Electricity ► Mains ► Direct Current

• Cells and batteries supply a current which always flows
in the same direction.

• This is called a direct current (d.c.).
Electricity ► Mains ► Oscilloscope Trace

a.c.                                 d.c.

•   Candidates should be able to compare the voltages of d.c.
supplies…

•   And the frequencies and peak voltages of a.c. supplies from
diagrams of oscilloscope traces.
Electricity ► Mains ► Safety

• If a fault in an electrical circuit or an appliance causes too great
a current to flow, the circuit is switched off by a

• fuse
• or a circuit breaker.
Electricity ► Mains ► Fuse

Normal                                            Fault

12 A                                     14 A

Fuse : 13 A                               Fuse : 13 A

• When the current through a fuse wire exceeds the current rating
of the fuse..

• The wire becomes hot and will (eventually) melt breaking the
circuit and switching off the current.
Electricity ► Mains ► Fuse selection

13                      The Goldilocks and the Three
Melts too late
Bears Theory of Fuse Selection™

10

Just right   5

Melts too soon    3
2

Safe   Dangerous

• The fuse should have a value higher than, but as close as possible
to, the current through the appliance when it is working normally.

• The manufacturer will normally recommend a fuse.
Electricity ► Mains ► Circuit Breaker

Normal                             Fault

Weak Magnetic Force                   Strong Magnetic Force

Safe Current                          High Current

•    A circuit breaker uses an electromagnet to detect a surge and
operate a very quick automatic off switch.

•    When the fault is fixed the circuit breaker can be reset.
Electricity ► Mains ► Earth Wire

No Earth Wire                        Earth Wire

Exposed Wire

• Appliances with metal cases need to be earthed.
• The earth pin is connected to the case via the yellow/green wire.
• If a fault in the appliance connects the case to the live wire, and the
supply is switched on, a very large current flows to earth and
Electricity ► Mains ► Live Wire

• The live terminal of the mains
supply alternates between a
positive and negative voltage
with respect to the neutral
terminal.

• The neutral terminal stays at a
voltage close to zero with
respect to earth.
Electricity ► Charge ► Idea Map

1.5             Extra Electrons
Electrons & Protons

Equal           Lack of Electrons

Negative            Neutral             Positive

Force                                    Force
Attraction

Uses

Photocopier      Electrolysis          Printer
Electricity ► Charge ► Balance of Protons and Electrons

Electrons
-
Protons           -
+ -           + -             +
+ -           + -             +
+ -           + -             + -

Extra Electrons        Equal        Lack of Electrons

Negative        Neutral            Positive
Electricity ► Charge ► Multiple Terms

•   Charge
•   Property of Electrons and Protons           Mean the same
•   Particles which can exert a force
•   Ability to create movement

•   Stationary Electrons
•   Electrostatics
•   Static Electricity
•   Static                                      Mean the same
•   Trillions of Electrons ‘flooding in’
•   Trillions of Electrons leaving an area
•   The balance between Electrons and Protons

•   Negatively Charged: Extra Electrons         Both Electrically Charged
•   Positively Charged: Electrons missing
Electricity ► Charge ► Phenomena

•   When certain different insulating materials are rubbed against each
other they become electrically charged.

•   Electrically charged objects attract small objects placed near to
them.
Electricity ► Charge ► Charges cause Repulsion and
Attraction

-
-
+ -                                       +
+ -                                       + -
-     -
-     -
+ -     - +
+ -     - +

•   When two electrically charged objects are brought close together,
they exert a force on each other.
•   These observations can be explained in terms of two types of charge
called positive (+) and negative (-).
•   Two objects which have the same type of charge repel.
•   Two objects which have different types of charge attract.
Electricity ► Charge ► Charge is conserved

Positive
Neutral                             Negative
Neutral

- +- - ++ - -                       - +- - ++ - -
+     +                             +     +
-
- + + + + ++                             -
- + + + + ++
- - - - + - -                       - - - - + - -
+           +                       +           +
+ + -- + - - -
- + -                                 + + -- + - - -
- + -
+     +                             +     +

•   When two different materials are rubbed against each other,
electrons, which have a negative charge, are rubbed off one material
on to the other.

•   The material which gains electrons becomes negatively charged. the
material which loses electrons is left with an equal positive charge.
Electricity ► Charge ► Discharge

•   A charged conductor can be discharged by connecting it to earth
with a conductor.
Electricity ► Charge ► Sparks

•   The greater the charge on an isolated object, the greater the voltage
(potential difference) between the object and earth.

•   If the voltage becomes high enough, a spark may jump across the
gap between the object and any earthed conductor which is brought
near it.
Electricity ► Charge ► Safety

• Refuelling can be
dangerous because a
spark could ignite the
fumes.

• A wire is used to conduct
the electrostatic charge
away safely (discharging).
Electricity ► Charge ► Metal

•   Metals are good conductors of electricity because some of the
electrons from their atoms can move freely throughout the metal
structure.
Electricity ► Charge ► Photocopier

•    Copying plate is electrically charged.
•    An image of the page you want to copy is projected on to the plate.
•    Where light falls on the plate, the Charge leaks away.
•    The parts of the plate that are still charged attract bits of black powder.
•    The black powder is transferred from the plate to a sheet of paper.
•    The paper is heated to make the black powder stick.
•    There is now a copy of the original page.

A
Electricity ► Charge ► Electrolysis

•     In solid conductors, an electric current is a
flow of electrons.

•     When some chemical compounds are
melted or dissolved in water they conduct
electricity.

•     These compounds are made up of
electrically charged particles called ions.

•     The current is due to negatively charged
ions moving to the positive terminal
(electrode) and the positively charged ions
moving to the negative electrode.

•     Simpler substances are released at the
terminals (electrodes). This process is
called electrolysis.
Electricity ► Charge ► Electrolysis Deposition

1 amp 1 min               2 amps 1 min              2 amps 2 min

•   During electrolysis the mass and/or volume of the substance
deposited or released at the electrode increases in proportion to:

•   The current.
•   The time for which the current flows.
Electricity ► Control ► Ideas Map

1.6
Sensor                      Capacitor

Variable Resistor
Modifiers
Potential Divider

Relay
Switches
Transistor

Logic Gates         Processor                    Time Delay

AND, OR, NOT
Output device
Electricity ► Control ► Electronic Systems

• Electronic systems have:

• Input sensors which detect changes in the environment.
• A processor which decides what action is needed.
• An output device creates a signal or action.
Electricity ► Control ► Input Sensors

• Input sensors include:

• Thermistors which detect changes in temperature
• LDRs which detect changes in light
• Switches which respond to pressure, tilt, magnetic fields or moisture.
Electricity ► Control ► Output Devices

M

• Output devices include:

•   Lamps and LEDs (light emitting diode) which produce light
•   Buzzers which produce sound
•   Motors which produce movement
•   Heaters which produce heat
Electricity ► Control ► Variable Resistor

•   The flow of electricity through a circuit (the current) can be
controlled by using a fixed or a variable resistor.
Electricity ► Control ► Potential Divider

POTENTIAL ENERGY

V in                      Thermistor      Variable Resistor
V out

•   The voltage that is supplied to the potential divider V in ….
•   is shared across the two resistors.
•   If either resistance is increased (or reduced), the share of the voltage across it
also increases (or reduces).
Electricity ► Control ► Equal Resistance

5000 Ω                                5V

4000 Ω                                4V

3000 Ω                                3V

2000 Ω                                2V

1000 Ω                                1V

0Ω                                 0V           Vout

•   If the two resistors change by the same amount..
•   They will continue to share the voltage equally
Electricity ► Control ► Unequal Resistance

5000 Ω                                 5V

4000 Ω                                 4V

3000 Ω                                 3V

2000 Ω                                 2V

1000 Ω                                 1V

0Ω                                   0V             Vout

•    It is the proportion of the resistance that is important.
•    Here the variable resistor setting affects V out.
Forces ► Idea Map

2
Contact
Friction                 Gravity

Field
Muscular                 Magnetism

Forces

Balanced                     Unbalanced                 Around Pivot   90o to Motion

No Acceleration                 Acceleration                 Moments        Circular

Constant Velocity             Changing Velocity

Graphs                       Momentum                     Mass
Forces ► Graphs ► Summary

2.1                                                    Graphs

Distance                                     Velocity

Stop                                          Constant Velocity

Velocity (m/s)
Distance (m)

Faster Constant Velocity                        Greater Acceleration

Constant Velocity                           Acceleration
Stop

Time                                        Time
Forces ► Graphs ► Distance Time

DISTANCE

TIME           TIME          TIME

Distance   =   Speed    x    Time
d       =       s    x      t
24 km     =   6 km/h   x   4 hours
Forces ► Graphs ► Distance II

•     On a distance-time graph :
•     Stationary objects are
represented by horizontal                                         Stationary
lines
•     Objects moving with a

Distance (m)
represented by sloping                                            Faster Constant
straight lines.                                                   Velocity
•     The steeper the slope of the
graph, the greater the speed
it represents.
•     If an object moves in a                                    Constant Velocity
straight line, how far it is                  Stationary
from a certain point can be                                Time
represented by a distance-
time graph.
Forces ► Graphs ► Velocity

Speed: Constant
Velocity : Constant
Direction: Constant

Speed: Constant
Velocity : Changing
Direction: Changing

•   The velocity of an object is its speed in a given direction.
Forces ► Graphs ► Velocity Time

VELOCITY

TIME                   TIME                      TIME

•   Velocity-time graphs can represent the motion of a body.
•   The steeper the slope of the graph, the greater the acceleration it represents
•   Constant velocity it is represented by a horizontal line.
•   Constant acceleration it is represent by a straight sloping line..
Forces ► Graphs ►Acceleration

VELOCITY
Velocity Change

Time

TIME

• The acceleration of an object is the rate at which its velocity changes.

• For objects moving in a straight line with a steady acceleration, the
acceleration, the change in velocity and the time taken for the change are
related as shown:

Velocity Change      =     Acceleration     x            Time
v-u     =           a          x              t
10 m/s   =         2 m/s2       x         5 seconds
Forces ► Graphs ► Gradient for Speed

DISTANCE

100 km ÷ 2 hr = 50 km/h

100 km
2 hr

TIME

• Candidates should be able to calculate the gradient / slope of a distance-
time graph.
Forces ► Graphs ► Gradient for Acceleration

VELOCITY

60 m/s ÷ 20 sec = 3 m/s2

60 m/s
20 sec

TIME

• Candidates should be able to calculate:
• The gradient of a velocity-time graph and interpret this as acceleration.
Forces ► Graphs ► Area for Distance

6 m/s                                  6 m/s

VELOCITY
VELOCITY

30m
15m
5 sec                                  5 sec

• The area under a velocity-time graph. for an object moving with constant
acceleration represents distance travelled.
Forces ► Acceleration ► Ideas Map

2.2                        Forces                         Newton

Balanced               Unbalanced

Constant Velocity          Acceleration                F = ma

eg 0 m/s or 10 m/s      eg 2 m/s2 or 9 m/s2
Forces ► Acceleration ► Horizontal

Acceleration   No         Acceleration   Yes
Speed          ?          Speed          ?
Direction      ?          Direction      ?
Forces ► Acceleration ► Vertical

Acceleration   No       Acceleration   Yes
Speed          ?        Speed          ?
Direction      ?        Direction      ?
Forces ► Acceleration ► Constant Motion

STOP

Balanced: 0 km/h                        Balanced: 60 km/h

• Balanced forces will have no effect on the movement of an object:
• It will remain stationary or,
• If it is already moving it will continue to move at the same speed and in the
same direction.
Forces ► Acceleration ► Balanced Forces

•   The forces acting on an object may cancel each other out
(balance).
•   When an object rests on a surface:
•   The weight of the object exerts a downward force on the surface
•   The surface exerts an upwards force on the object
•   The sizes of the two forces are the same
Forces ► Acceleration ► Unbalanced Forces

• If the forces acting on an object do not cancel each other out…
• An unbalanced force will act on the object.
Forces ► Acceleration ► Scenarios

• A stationary object
will start to move in
the direction of the
unbalanced force

• An object moving in
the direction of the
force will speed up

• An object moving in
the opposite direction
to the force will slow
down
Forces ► Acceleration ► Size of Resultant Force

VELOCITY
VELOCITY
VELOCITY
•   The greater the force, the greater the acceleration.
Forces ► Acceleration ► Effect of Mass

• The bigger the mass of an object…
• The greater the force needed to give the object a particular acceleration.
Forces ► Acceleration ► Newton

3

Speed (m/s)
2

1
1 kg
0
0        1       2    3
Time (sec)

• One newton is the force needed to give a mass of one kilogram an
acceleration of one metre per second squared.
• Force, mass and acceleration are related as shown:

Force                   =       Mass         x    Acceleration
F                   =        m           x          a
100 Newton                 =       2 Kg         x        50 m/s2
Forces ► Acceleration ► Falling Objects

4 kg
2 kg
1 kg
Forces ► Acceleration ► Falling Objects II

Acceleration          =       Force (Weight)         ÷      Mass
x Gravity (10 N/kg)

40 N
20 N
10 N
a=               =              =            = 10 m/s2
1 kg
2 kg
4 kg

• Therefore, all objects fall at the same
speed irrespective of mass
• (if we ignore air resistance, Friction)
Forces ► Acceleration ► Effect of Friction

• Air Friction changes the situation

• Acceleration = Resultant Force (Weight – Friction) ÷ Mass
• Friction makes some of the weight effectively unavailable.

-5N

40 N         -5N
20 N
-5N
≠           ≠
1 kg
2 kg
4 kg
Forces ► Acceleration ► Changing Mass

Mass    Gravity   Weight   Distance   Friction   Resultant   Acceleration   Time
kg      N/kg       N         m          N          N           m/s2          s
1        10       10          2         5            5           5.00    0.89
2        10       20          2         5           15           7.50    0.73
3        10       30          2         5           25           8.33    0.69
4        10       40          2         5           35           8.75    0.68
5        10       50          2         5           45           9.00    0.67
6        10       60          2         5           55           9.17    0.66
7        10       70          2         5           65           9.29    0.66
8        10       80          2         5           75           9.38    0.65
9        10       90          2         5           85           9.44    0.65
10        10      100          2         5           95           9.50    0.65
Forces ► Acceleration ► Mass vs Descent Time

0.95

0.90

0.85

0.80
Time (s)

0.75

0.70

0.65

0.60

0.55

0.50
0   2         4         6          8   10   12
Mass (Kg)
Forces ► Acceleration ► Effect of Friction

• If area changes, friction changes (eg Larger Parachute)

• Acceleration = Resultant Force (Weight – Friction) ÷ Mass
• Friction makes some of the weight effectively unavailable.

-5N         - 10 N       - 15 N

40 N         40 N         40 N

≠            ≠

4 kg         4 kg         4 kg
Forces ► Acceleration ► Changing Friction

Mass    Gravity   Weight   Distance   Friction   Resultant   Acceleration   Time
kg      N/kg       N         m          N          N           m/s2          s
70        10      700          2       100          600           8.57    0.68
70        10      700          2       150          550           7.86    0.71
70        10      700          2       200          500           7.14    0.75
70        10      700          2       250          450           6.43    0.79
70        10      700          2       300          400           5.71    0.84
70        10      700          2       350          350           5.00    0.89
70        10      700          2       400          300           4.29    0.97
70        10      700          2       450          250           3.57    1.06
70        10      700          2       500          200           2.86    1.18
70        10      700          2       550          150           2.14    1.37
Forces ► Acceleration ► Friction vs Descent Time

1.50

1.40

1.30

1.20

1.10
Time (s)

1.00

0.90

0.80

0.70

0.60

0.50
0   100       200         300          400   500   600

Friction (N)
Forces ► Acceleration ► Time Formula

acceleration      = velocity change ÷                  time
a            =       v-u       ÷                    t
1.                    v            =         u       +                    at

average speed =            distance          ÷           time
2.               (u + v) ÷ 2    =             s             ÷             t
1. into 2.     (u + u + at) ÷ 2 =             s             ÷             t

u is zero so…
½at     =               s             ÷             t
s      =              ½at2
2s ÷ a   =               t2

t          =      √(2s ÷ a)

s = distance travelled u = initial velocity v = final velocity a = acceleration t = time taken
Forces ► Acceleration ► Equal and Opposite

•   Whenever two bodies interact…

•   The forces they exert on each other are equal and opposite.
Forces ► Acceleration ► Unbalanced Forces

•   If the surface is not strong enough… we have a problem.
Forces ► Friction ► Ideas Map

2.3                                      Friction

Fluids                             Solid

Brakes
Air            Water

Reaction       Braking
Friction = Weight
Stopping
Terminal Velocity
Forces ► Friction ► Types

• A force of friction acts

• When an object moves through air or water
• When solid surfaces slide (or tend to slide) across each other.
Forces ► Friction ► Effects

friction

•   The direction of this force of friction is always opposite to the
direction in which the object or surface is moving.

•   Friction causes objects to heat up and to wear away at their
surfaces.

•   The friction between solid surfaces is used in brakes which slow
down and stop moving vehicles.
Forces ► Friction ► Braking

SPEED

TIME

• The greater the speed of a vehicle:

• The greater the braking force needed to stop it in a certain distance
• The greater the distance needed to stop it with a certain braking force
Forces ► Friction ► Skidding

•   If too great a braking force is applied…

•   Friction between a vehicle's tyres and the road surface may not be
great enough to prevent skidding.
Forces ► Friction ► Stopping Time

reaction time

braking time
Speed

long stopping distance

short stopping distance

Stopping time
•    The overall stopping distance is greater if:                    •   The stopping distance of a
•    The vehicle is initially travelling faster                          vehicle depends on:
•    The driver's reactions are slower (due to                       •   The distance the vehicle travels
tiredness, drugs, alcohol)                                          during the driver's reaction time.
•    There are adverse weather conditions                            •   The distance the vehicle travels
(wet/icy roads, poor visibility)                                    under the braking force.
•    The vehicle is poorly maintained (e.g. worn
brakes/tyres)
Forces ► Friction ► Terminal Velocity

terminal velocity

deceleration
acceleration

on ground
terminal velocity
weight

friction
force

60 m/s                                      4 m/s
time

•             The faster an object moves through a gas or a liquid (a fluid) the greater
•             the force of friction which acts on it. When a body falls:

•             Initially it accelerates due to the force of gravity
•             Frictional forces increase until they balance the gravitational forces
•             The resultant force eventually reaches zero and the body falls at its
terminal velocity
Forces ► Friction ► Terminal Velocity II

Friction

Weight

Friction = Weight   therefore there is no acceleration
Forces ► Friction ► Driving

frictional forces                        driving force

•   When a vehicle has a steady speed …
•   The frictional forces balance the driving force.
Forces ► Momentum ► Ideas Map

2.5                        Mass

x
Before Collision

After Collision

Before
Objects have…            Velocity
After
=

Momentum               Before

After

Before              After
Forces ► Momentum ► Impact

Question: Would you rather be hit with a heavy or a light object?

Answer: It depends on its speed.
Forces ► Momentum ► Elephant vs Cheetah

• The greater the mass of an object…
• and the greater its speed in a particular direction (its velocity)…
• the more momentum the object has in that direction.

• Momentum has both magnitude (size) and direction.
Forces ► Momentum ► Calculation

Momentum, mass and velocity are related as shown:

Momentum     =         Mass         x       Velocity
960 kg m/s   =        120 kg        x        8 m/s
Forces ► Momentum ► Collision

•   When an object collides with another..
•   The two objects exert a force on each other.
•   These forces are equal in size but opposite in direction.
•   Each object experiences a change in momentum which is equal in
size but opposite in direction.
Forces ► Momentum ► Collision Calculation

2 Kg x 10 m/s               5 Kg x 6 m/s             2 Kg x 5 m/s         5 Kg x 8 m/s

50 Kg m/s                                       50 Kg m/s

•   When a force acts on an object that is moving, or able to move…
•   A change in momentum occurs.

•   In any collision/explosion…
•   the momentum after the collision/explosion is the same as…
•   the momentum before the collision/explosion. (for a particular direction)
•   Momentum is conserved when no other/external forces act on the
colliding/exploding object(s).
Forces ► Momentum ► Collision Calculation II

•   The force, change in momentum and the time taken for the change
are related as shown:

•   Momentum Change (Impulse)       =        Force     x   Time
10 Kg m/s                       =        1,000 N   x   0.01 s
Forces ► Momentum ► Kinetic Energy

• When objects collide, the total kinetic energy after the collision in a
particular direction is normally less than before the collision.

• Elastic collisions are those involving no overall change in kinetic energy
Energy ► Work ► Ideas Map

5.4                                Energy (J)

Useful Energy            Wasted Energy

Power (J/s)             Work (J)

Calculated by                Gravity

Movement against force            Elastic

Inertia

Friction
Energy ► Work ► Joule
James Prescott Joule (1818 - 1889)

1.0 J

0.8 J

0.6 J              1 metre

0.4 J

0.2 J

0.0 J   1 Newton

• Energy is measured in joules (J).
Energy ► Work ► Examples

10,000,000,000,000,000,000,000,000 J                              100,000,000,000,000,000 J

100 J

1,000,000,000,000,000 J 10,000,000,000,000 J   100,000,000 J                  1,000 J
Energy ► Work ► Effect of Force

• When a force moves an object, energy is transferred.

• Energy transferred is also called work
Energy ► Work ► Calculation

Force

Distance

Energy    =        Force   x   Distance
E      =          F     x      d

9,000 J   =        900 N   x    10 m
Energy ► Work ► Gravitational Potential Energy

• Gravitational potential energy
is the energy stored in an
object

• Energy is stored because the
object has been moved against
the force of gravity.

Work                  =   Force    x          Distance
Gravitational Potential Energy    =   Weight   x    Change in Height
GPE                  =     W      x            Δh

50 J                 =    10 N    x            5m

10 N
Energy ► Work ► Mass, Gravity and Weight

MASS
GRAVITY FIELD
WEIGHT
MASS

Force on mass       Amount of matter        Region of influence

Weight   =        Mass          x    Gravity
W   =         m            x       g

10 N    =        1 kg          x    10 N/kg
Energy ► Work ► Elastic Potential Energy

• Elastic potential energy is the
energy stored in an elastic
object.

• Energy is stored when work is
done on the object to change
its shape.

Catapult designed by Leonardo da Vinci
Energy ► Work ► Kinetic Energy

• Kinetic energy is the energy an
object has because of its
movement.

• An object has more kinetic
energy:

• The greater its mass (and
therefore inertia.

• The greater its speed

Kinetic Energy    =           ½ Mass      x   Speed²
KE          =            ½m         x      v²
10 J         =          0.5 x 5 kg   x   4 (m/s)2
Energy ► Work ► Power

200,000,000 W                    500,000 W

• Power (Watts) is a measure of how fast energy is transferred.
• The greater the power, the more energy is transferred in a given time

Energy      =        Power         x         Time
E      =          P           x           t

5,000,000 J   =    500,000 Watts     x          10 s
Energy ► Work ► Power and Human Activity

Power (W)            Activity

700                  cycling (21 km/h)
685                  climbing stairs (116 steps/min)
545                  skating (15 km/h)
475                  swimming (1.6 km/h)
440                  playing tennis
400                  cycling (15 km/h)
265                  walking (5 km/h)
210                  sitting with attention focused
125                  standing at rest
120                  sitting at rest
083                  sleeping

6                                    Atoms

Decay                Structure

Types              Properties      Uses
Radioactivity ► Types ► Ideas Map

Alpha

6.1                           Types        Beta

Gamma

Background
Source
Specific

Speed of Decay                    Measuring

Half Life              Uses    Sterilisation

Tracer

•   Every thing is made of atoms

•       Iron on Copper The Kanji
characters for "atom."
Radioactivity ► Types ► Stable vs Unstable

•   There are two kinds of atoms…

Stable                               Unstable:
Radioactivity ► Types ► Alpha Beta Gamma

•    Unstable atoms emit 3 types of radiation…

2 Protons
ALPHA                                                   2 Neutrons

BETA                                                    High Energy
Electron

ALUMINIUM
High
PAPER

GAMMA

Frequency
Wave

loft insulation

carpets
• There are radioactive substances all around us, including in the ground, in
the air, in building materials and in food.
• Radiation also reaches us from space.

-1

-1                                       -1

Normal Atom                                      Ion

atoms or molecules these may become charged (ionised).
•   When radiation ionises molecules in living cells it can cause
damage, including cancer.
•   The larger the dose of radiation the greater the risk of cancer.

• Higher doses of ionising radiation can kill cells.
• they are used to kill cancer cells and harmful microorganisms.
Radioactivity ► Types ► Measuring Thickness

•   As radiation passes through a material it can be absorbed.
•   The greater the thickness of a material the greater the absorption.
•   The absorption of radiation can be used to monitor/control the
thickness of materials.
Radioactivity ► Types ► Interaction with Body

least        ALPHA
dangerous
BETA
most
dangerous
GAMMA

most
dangerous

least
dangerous

Used as tracer
Radioactivity ► Types ► Monitoring Dosage

Low Dosage               High Dosage

monitor the amount of radiation they have been exposed to over a
period of time.
• The badge is a small packet containing photographic film.
• The more radiation a worker has been exposed to, the darker the film
is when it has been developed.
Radioactivity ► Types ► Half Life

100

Undecayed Atoms
50

0

0     14       28
Time (s)
•   The half-life of a radioactive substance:
•   Is the time it takes for the number of parent atoms in a sample to halve.
•   Is the time it takes for the count rate from the original substance to fall to
half its initial level.
Radioactivity ► Structure ► Ideas Map

6.2                             Atomic Structure

Discovery                Nucleus

Scattering Exp.           Nucleons

Proton         Neutron             Electron

Type of atom              Isotope        Fission

Element                 Dating
Radioactivity ► Structure ► Relative Size

Neutron        Proton        Electron

• Atoms have a small central nucleus made up of protons and neutrons
around which there are electrons.

• To scale above nucleus would be size of a grain of sand.
Radioactivity ► Structure ► Rutherford Expectation

•    The ‘plum pudding’ model of matter said
that atoms were solid and uniformly

(1871 - 1937)
Lord Ernest Rutherford
positive with specks of negativity.

•    If this was the case even a small thickness
of material should block a stream of alpha
particles.

•    Ernest Rutherford decided to test this idea

What they expected….

alpha particle source                         alpha detectors
gold leaf
Radioactivity ► Structure ► Rutherford Result

•    What actually happened….

straight
through

deflection
reflected back

•   Conclusion 1 : The plum pudding model must be wrong
Radioactivity ► Structure ► Rutherford Conclusion

•   Conclusion 2 : Nuclei are positive and far apart

+
+

+
+

+
+

simplified gold nucleus

Electron

Neutron

•   Kilograms are inconvenient for such tiny masses…
•   So the Atom Mass Unit was invented.
•   Protons and neutrons weigh 1 AMU by definition, an electron is 1/2000 AMU

+   =   20
=   10   Ne

•   The number of electrons is equal to the number of
protons in the nucleus therefore…
•   The atom as a whole has no electrical charge.
•   10 - 10 = 0
•   The total number of protons and neutrons (nucleons)
in an atom is called its mass (nucleon) number.
Radioactivity ► Structure ► Proton Number

3 protons therefore Lithium

•   All atoms of a particular element have the same number of protons.

3 protons therefore
1 proton therefore                         Lithium               4 protons therefore
Hydrogen             2 protons therefore                         Berylium
Helium

•   Atoms of different elements have different numbers of protons.

2 extra
normal                               neutrons           3 extra
Hydrogen          1 extra                               neutrons
neutron

isotopes of hydrogen

•   Atoms of the same element which have different numbers of
neutrons are called isotopes.
Radioactivity ► Structure ► Beta Decay

unstable nuclei. When an unstable nucleus splits up (disintegrates):

•   A different atom, with a different number of protons, is formed.
•   For each electron emitted, a neutron in the nucleus becomes a proton.

•   Nuclear reactors use a process called nuclear fission. When an
atom with a very large nucleus is bombarded with neutrons:

•   The nucleus splits into two smaller nuclei.
•   Further neutrons are released which may cause further nuclear
fission resulting in a chain reaction.
•   The new atoms which are formed are themselves radioactive.
Radioactivity ► Structure ► Comparative Energies

=
3,500,000 g of Coal                                1 g of Uranium

• The energy released by an atom during radioactive disintegration or
nuclear fission is very large compared to the energy released when a
chemical bond is made between two atoms.
Radioactivity ► Structure ► Carbon Dating

The tomb of Rameses IX lies                     Wooden Bowl dated
in the centre of the Valley of                     to 1000 BC
the Kings

•   The older a particular radioactive material, the less radiation it emits.
•   This idea can be used to date materials, including rocks.
Radioactivity ► Structure ► Carbon Dating

100%

74%

5,000yr        10,000yr

•   The half life of Carbon 14 is 5,730 years.
•   During one half-life, half of the radioactive atoms initially present in
a sample decay. This idea can be used to date materials.
Radioactivity ► Structure ► Non-Carbon Dating

58%
42%

•   Uranium isotopes, which have a very long half-life, decay via a
series of relatively short-lived radioisotopes to produce stable
•   The relative proportions of uranium and lead isotopes in a sample
of igneous rock can, therefore, be used to date the rock
•   The proportions of the radioisotope potassium-40 and its stable
decay product argon can also be used to date igneous rocks from
which the gaseous argon has been unable to escape.
End of main section
► Key Terms

ELECTRICITY                        FORCE               WAVES                       SPACE                     ENERGY                           RADIOACTIVITY
Alternating current                Acceleration        Amplitude                   Artificial satellite      Conduction                       Activity
Ammeter                            Air resistance      Analogue signal             Big bang                  Convection                       Alpha
Ampere                             Braking distance    Compression                 Black hole                Efficiency                       Atom
Anode                              Centre of mass      Converging lens             Comet                     Elastic potential energy         Atomic number
Battery                            Centripetal force   Core                        Fusion                    Electrical energy                Background radiation
Capacitor                          Decelerate          Crests                      Galaxy                    Fossil fuels                     Beta
Cathode                            Drag                Critical engle              Geostationary satellite   Free electrons                   Chain reaction
Cell                               Elastic collision   Crust                       Gravity                   Generator                        Cosmic ray
Charge                             Friction            Cycle                       Light year                Geothermal energy                Count rate
Circuit breaker                    Gravity             Diffraction                 Milky way                 Global warming                   Decay
Conductor                          Kinetic energy      Digital signals             Moon                      Gravitational potential energy   Electrons
Core                               Mass                Diverging lens              Orbit                     Greenhouse effect                Electromagnetic spectrum
Coulomb                            Moment              Electromagnetic spectrum    Planet                    Hydroelectric                    Element
Current                            Momentum            Electromagnetic waves       Red planet                Kinetic energy                   Gamma
Diode                              Newton              Fetal imaging               Red giant                 Non-renewable resources          Gieger-Muller tube
Direct current                     Pivot               Fetus                       Red shift                 Power                            Half-life
Dynamo                             Speed               Focus                       Satellite                 Radiation                        Ionise
Earthing                           Terminal velocity   Frequency                   Solar system              Renewable energy                 Isotope
Electrical energy                  Thinking distance   Hertz                       Star                      Turbine                          Mass number
Electrical charge                  Velocity            Lithosphere                 Sun                       Work                             Neutron
Electric current                   Weight              Longitudinal wave           Universe                                                   Nuclear fission
Electrode                                              Magma                       White dwarf                                                Nucleon
Electrolysis                                           Mantle                                                                                 Nucleus
Electrolyte                                            Normal                                                                                 Proton
Free electron                                          Seismic waves                                                                          Radioactive tracer
Generator                                              Subduction zone                                                                        Random
Hertz                                                  Tectonic plates
Input sensor                                           Total internal reflection
Insulation                                             Transverse waves
Insulator                                              Troughs
Ion                                                    Ultrasound
Ionise                                                 Vibration
Joule                                                  Virtual image
Kilowatt                                               Wavelength
Kilowatt hour                                          Waves
Light-dependent resistor                               Wave speed
Logic gate
Magnet
Magnetic field              Resistor
Motor effect                Secondary coil
Ohm                         Solenoid
Output device               Thermistor
Parallel/series circuits    Transformer
Potential difference        Transistor
Potential divider           Volt
Power                       Voltage
Primary coil                Voltmeter
Processor                   Watt
Relay
Resistance
► Connections

Output device
Watt          Joule     Transistor      Logic gate                            resistor            Gravity            Terminal velocity
Processor
Element                                                                                      Thermistor
Mass number                 Power                                                                Velocity
Isotope                                                  Kilowatt hour            Input sensor                                                Weight
Potential divider             Energy                                                                 Decelerate
Atomic number                                            Ohm                                                            Direction
Neutron                                                                Kilowatt                               Speed
Drag
Proton                                                                                                       Relay                                Air resistance
Potential difference      Resistor               Insulator                                    Graphs
Nucleon                                                                                                                                                         Braking
Voltage               Hertz             Cost                                      Acceleration                          distance
Nucleus                Resistance                                                                            Friction
Stopping       Thinking
Chain reaction                           Electrons                                                                           Forces                    Distance       distance
Voltmeter                  Mains
Nuclear fission Emissions Decay Atom                                                             Charge                                                  Moments     Centre of
Voltage                                                                    Momentum
Circular                              mass
Structure                                                                                                      Mass
Random    Dating                                                                                   Newton
Gieger-Muller tube                                                                                                                                                        Pivot
Tracer                       Circuits                                                          Centripetal force
Alpha           Uses
Count rate
Beta                                                                                         Cycle                          Elastic collision Kinetic energy
Half-life  Cosmic ray     Gamma                                                                                                         Troughs
Crests
Secondary coil                                         Wave speed                                          Amplitude
Electromagnetic spectrum                                                                                        Frequency
Generator                                                            Wavelength
Primary coil                                                                                                                               Normal
Magnet                                                                                                                                               Diffraction
Turbine                                        PHYSICS
Electrical energy                      Transformer                                           Longitudinal
Magnetic field                                                                                                                                            Refraction       Critical angle
Induction                                                                   Characteristics
Motor effect           Solenoid                                                                              Transverse                        Total internal reflection
Energy                           Space                                                 Converging lens               Virtual image
Electromagnetism
Global warming                                                                                                             Waves Optical                               Focus     Real image
Fossil fuels                                                 Big bang                                                   Diverging lens      Ultrasound
Thermal                             Solar                                                                    Fetal imaging
Greenhouse effect              Resources                                                                         Comet                             Sound
Non-renewable                         Conduction                                 Solar system                                                              Rarefraction
Convection      Universe                                                                 Vibration
Geothermal
Renewable                     Efficiency      Radiation                                                         Tectonic           Seismic                 Compression
Sun
Magma
Black hole              Red shift                                                                     Crust
Hydroelectric                        Gravitational                     Galaxy               Planets                                      Core
Orbit                                                          Lithosphere
Work potential energy                                                            Electromagnetic                                  Mantle
Kinetic energy                                       Milky way                                                               Subduction zone
Star              Satellite            Spectrum
Power
Light year                            Moon Artificial satellite                                  Seismograph
Elastic potential                                 Red giant
energy                           Fusion                              Geostationary
Polar                                Digital signals S waves P waves
White dwarf                          Analogue signal
ELECTRICITY ► phenomena explained by electrons

ATOM small unit of matter

ELECTRON part of atom, can leave                                                                                                                          PROTON part of atom, cannot leave

PROPERTIES                                                                         MEASUREMENT                                              EFFECTS
what features or attributes does an electron have                                  what units are used to count electrons                   things that happen because of electrons

ABILITY TO MAKE THINGS MOVE
charge, there are two types. negative and positive
WORDS FOR LARGE NUMBERS                                  MOVING ELECTRONS                                              STATIONARY ELECTRONS
are convenient eg the word ‘year’                        current, flow of charge, electricity                          very large numbers of electrons grouped together. static electricity, ’static’, electrostatics
ELECTRONS HAVE A NEGATIVE CHARGE
sometimes electrons are referred to as ‘charge’.
The charge on proton is positive                                                                                                                                                                          EXTRA ELECTRONS                    NORMAL NUMBER OF                      LACK OF ELECTRONS
COULOMB                                                                                                                negatively charged                 ELECTRONS                             positively charged
a word for a large number of electrons                                                                                                                    no charge, neutral

REPELLED                         ATTRACTED                                                                                                                                                                    - - - - -                           - - -                                -
move away from other             move towards
electrons                        protons                                                                                                                                                                     + + +                                + + +                                + + +

- -                          -              +
1.          Electrons move round circuits
2.          A circuit is a number of components eg bulbs connected by wires                                            1. Charged objects attract neutral ones
3.          A battery provides a stream of electrons                                                                   2. Positive and negative objects attract
3. Like charged objects repel

MEASUREMENT                                         ENERGY                                        TYPES OF MOVEMENT                                                                           EASE OF MOVEMENT
how many electrons passing a point                  electrons can deliver energy

BACKWARDS AND FORWARDS                    ALWAYS ONE WAY                                    EASY                           DIFFICULT                  SOMETIMES                  IMPOSSIBLE
alternating current                       direct current                                    conductor eg copper                                       DIFFICULT                  insulator eg plastic
ELECTRONS PER SECOND                                ENERGY PER ELECTRON
measured in amps                                    measured in volts

MAINS                                     BATTERY
WHEN DARK
delivers energy to the home
light dependent

Environment
resistor

Dependent
ENERGY DELIVERED PER SECOND measured in watts, joules per second

ENERGY COSTS                    EXCESSIVE ENERGY IS DANGEROUS
WHEN COLD
MONEY
thermistor

DIFFICULTY SET BY USER
IF 1000 JOULES of               SAFETY MEASURES                                                                                                                      variable resistor
energy is delivered per
second…
WIRE IS LONG
INDIRECT                       DELIBERATE WEAK                AUTOMATIC OFF SWITCH
CONTROL                        POINT
…for 1 HOUR
WIRE IS THIN
RELAY                          FUSE                           CIRCUIT BREAKER
..the electricity company       a small safe                   when the current surges        very quick off switch
call it a UNIT or               current switches               a thin section of wire
kilowatthour…a unit             on a big unsafe                melts                                                                                                 POOR CONDUCTOR
costs about £0.08               current                                                                                                                              fixed resistor
FORCE AND MOTION ► a push or a pull which creates movement

OBJECTS HAVE...

VELOCITY                                                          CONSTANT VELOCITY eg 0 m/s or 100 m/s             BALANCED FORCES                            FORCES ACTING ON THEM

CHANGING VELOCITY                                 UNBALANCED FORCES

SPEED m/s               DIRECTION
GRAPHS
representing   CHANGING SPEED                          CHANGING DIRECTION                                   EXAMPLES                                               CHARACTERISTICS
motion                                                                                                                                                             how can we describe a
TIME                    DISTANCE                                                                                                                                                                                      force
seconds                 metres
CONTACT           NON►CONTACT
INCREASE                 DECREASE       TEMPORARY FORCE                   CONSTANT FORCE     FORCES            FORCES
acceleration             deceleration   direction changes                 direction always   muscular,         field forces. gravity,
changes            friction          magnetism
CONSTANT SPEED

D                   S
Circular
Mass
T                     T                                                                               eg ball swung round on a string
moon orbiting earth                                  SIZE                                       DIRECTION
measured in newtons

CHANGING SPEED                                                     Momentum

D                   S                                                                                                                                                                                                   Terminal Velocity

friction
T                     T

Friction = Weight
Acceleration = 0
weight         Speed = 60 m/s
braking
stop
sober, well rested, good brakes, dry road

braking
stop
WAVES ► movement of energy but not matter

TYPES OF MOVEMENT

SIDE TO SIDE                 UP AND DOWN                       A to B

OSCILLATION also known as vibration

KNOCK-ON EFFECTS                ISOLATED
original movement               original
causes movement                 movement only
elsewhere

WAVES

CHARACTERISTICS                                  BEHAVIOUR                                                                                 TYPES
how do we describe waves                         what do waves do

How big is the oscillation?
The AMPLITUDE is 2 metres                                                                                                                  OSCILLATION IN                                                     OSCILLATION AT 90O
CHANGE SPEED                  SPREAD OUT                      CHANGE                      DIRECTION OF                                                       TO DIRECTION OF
eg moving from air            when passing thru a             DIRECTION                   TRAVEL                                                             TRAVEL
How long is the wave from peak to peak?          to glass                      gap: diffraction                                            longitundinal waves                                                transverse waves
The WAVELENGTH is 5 metres

How often does a wave pass?
The FREQUENCY is 2 waves per second or 2 hertz

BOUNCING OFF                         BENDING                                              Sound                    SLINKY                      ROPE               SEA WAVES             ELECTROMAGNETIC
How fast is the wave travelling?                 reflection                           light refracts when it hits glass at an                                                                                                            300,000 km/s
The SPEED of the wave is 10 metres per second                                         angle                                                                         EARTHQUAKES

SINGLE             MANY PARALLEL WAVES
WAVE                                                                                       GAMMA           X RAY            ULTRAVIOLET          LIGHT           INFRARED          MICROWAVE             RADIO
AMPLITUDE

CAN CARRY INFORMATION analogue or digital

BENT TOWARDS                           BENT AWAY FROM
each other by a convex lens            each other by a concave lens

WAVELENGTH

distorted wave still readable as 1 or 0

digital is better because the message is preserved even if
the wave is distorted
SPACE ► universe, galaxy, solar system, star, planet, satellite

UNIVERSE
everything we can see

HISTORY                                                                                                 STRUCTURE                                                                                      LIFE
Evidence for

PAST                         PRESENT                       FUTURE
DIRECT                                   INDIRECT

MASSIVE                      EXPANDING                     CONTRACTION?
EXPLOSION                                                  Big Crunch?                                  OUR GALAXY                                                 OTHER GALAXIES                      Finding live          Broadcast          Chemical changes
Big Bang                                                                                                100 billion stars called the milky way                     100 billion                         or fossilised         signals            in atmosphere
organisms                                Eg O2

EVIDENCE FOR EXPANSION

RED SHIFT
light from distance stars has a longer wavelength                                                       STARS
than we would ‘expect’ if universe were static                                                          massive nuclear furnaces

OUR STAR, THE SUN                                                                                                  ENERGY SOURCE                                     LIFE CYCLE
is orbited by..

NUCLEAR FUSION
THE EARTH                                                         8 OTHER PLANETS                                  hydrogen and helium fusing together to create..   PAST                                PRESENT                  FUTURE
is orbited by..                                                                                                                                                      gravity pulls dust together.        expansive nuclear
fusion begins                       forces = gravity

Mercury, Venus, (Earth),
Mars, Jupiter, Saturn,                           HEAT AND               HEAVIER ATOMS
SATELLITES                                                        Uranus, Neptune, Pluto                           LIGHT                  which make life possible
objects held in circular path by earth’s gravity                                                                                          eg carbon

MEDIUM STAR              BIG STAR          VERY BIG
STAR
NATURAL                       ARTIFICAIL

expansive forces win over gravity

MOON                          USES                                                                                 TYPES OF ORBIT
causes tides
STAR SWELLS              STAR EXPLODES
into a red giant         supernova

BLACK HOLE
ultra dense, no
MONITOR EARTH                      MONITOR SPACE                        COMMUNICATIONS                APPARENTLY FIXED IN THE SKY                   MOVES IN THE SKY                                                                            light escapes
weather, military                  eg hubble space telescope                                          geostationary orbit                           polar orbit
ENERGY ► the ability to make things happen

ENERGY

TYPES                                                                                                                                                              CHARACTERISTICS

POTENTIAL ENERGY stored energy                                                           KINETIC ENERGY movement energy

LARGE SCALE can see                          SMALL SCALE can’t see                       LARGE SCALE can see                                                   SMALL SCALE can’t see                           MEASURED in joules

CANNOT BE DESTROYED
MATERIAL          HEIGHT                     BONDS BETWEEN           UNSTABLE            MOVING CAR                   ROTATION            CURRENT              ELECTRONS              ATOMS
UNDER             gravitational potential    ATOMS                   ATOMS                                            of magnet           CREATES              FLOWING                VIBRATING
TENSION           energy                     chemical                nuclear                                                              MOVEMENT             magnetic field         heat or thermal
strain                                                                                                                                    motor                created                energy                   CANNOT BE CREATED

MOVEMENT                                                             ENERGY CAN CHANGE
CREATES                                                              TYPE
eg bow and        eg water behind dam,       eg coal, gas, oil,      eg uranium                                                           CURRENT                                                              rate of change is measured
arrow, spring     sky diver                  wood                                                                                         generator                                                            in watts

VIBRATIONS CAN SPREAD IN 3 WAYS

F
STORED ENERGY eg petrol is changed into…
D                                   1. ATOMS                   2. ATOMS MOVE TO A          3. WAVE
D                                                      COLLIDE WITH               NEW LOCATION                TRANSMISSION
D                                                F
F
NEIGHBOURS
conduction                                                                            ENERGY USEFUL TO                  ENERGY NOT USEFUL TO
HUMANS                            HUMANS
known as work                     known as dissipated energy
eg a moving car                   eg heat from car engine
eg saucepan                eg boiling water            eg warmth from
base                                                   sun
GREATER FORCE means greater energy
maximising the useful energy
makes the car EFFICIENT
GREATER DISTANCE means greater energy

MAGNET MOVING                                                                       WIRE MOVING

S      N                                        S      N                                                             N                    S
N                      S

Creating current without contact (Induction)
RADIOACTIVITY ► fast moving particles and high energy waves

ATOM
small unit of matter

STRUCTURE                                                                                                                                                       STABILITY OF ATOM
what is an atom made of

STABLE ATOMS                       UNSTABLE ATOMS
CENTRAL CORE                                                       OUTER CLOUD                                                                                  stay the same forever              break apart, pop, decay RANDOMLY
nucleus                                                                                                                                                                                            by kicking out (emitting) particles and energy

.
NUCLEON
very small unit of matter                                                                                    HOW UNSTABLE IS THE ATOM?                                 FORMATION                                                  WHAT ATOMS EMIT                        BLOCKED BY

.                                                    how long does it take for…                                                                                                                                  (absorbed by)

ALL ATOMS              HALF THE ATOMS

aluminium

card
TO DECAY               TO DECAY                           NATURAL           UNNATURAL                                2 PROTONS & 2 NEUTRONS

.
EMITTED
PROTON                              NEUTRON                        ELECTRON                                  DIFFICULT              EASY
smallest unit of matter                   TO PREDICT             TO
positively charged                  not charged                    negatively charged                                               PREDICT                            bombarded with neutrons
(exerts a force)                    (exerts no force)              (exerts a force)

CONTROLLED                RAPID
1 ELECTRON
EMITTED
.
VERY                          VERY                        nuclear reactor           nuclear
UNSTABLE                      STABLE                                                bomb
short half►life               long half►life
HIGH ENERGY WAVE EMITTED
DESCRIPTION AND NOTATION

50%                             50%
TYPES OF ATOM elements
1ms                            1mil. yr.

normal atom                                               HYDROGEN ATOMS                                                                                                                                                        MEDICAL USE
always have one proton

isotopes have
extra neutrons
alpha

INSIDE BODY
HELIUM ATOMS                                                                                                                                                          beta                                     tissue cell: live
always have two protons
Rutherford used alpha particle to show that nuclei are far apart                                              gamma
a LITHIUM ATOM
always has three protons                                                          1%                                                                                                                           damaged cell

OUTSIDE BODY
1%                                                alpha
mass number
7
proton number
Li           chemical
98%
beta

3              symbol
protons in
atoms
protons in
alpha particles
gamma
like charges repel

Frequency (f)     Wavelength (λ)
Acceleration (a)     Time (t)

Mass (m)              Velocity (v)

Gravitational Field
Strength (g)                          Momentum
Current (I)

Force (F)                              Resistance (R)
v2                                                                     Charge (Q)
½m
Weight (w)                 Distance (d)
Impulse                  Voltage (V)
Change in                                      Moment
Height (Δh)
Power (P)

GPE     KINETIC              WORK              ELECTRICAL       ELECTRICAL

Energy (E)
Efficiency                                                                                                  Unit Cost

Useful Energy                                                                             Total Cost

```
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
 views: 17 posted: 11/3/2012 language: English pages: 163