AQA GCSE PHYSICS

SeismicTectonic

Main Contents

PHYSICS

ElectricityForces

Waves

Radioactivity

Space

Energy

Voltage

Energy

Mains Cost Charge Control

Graphs

Acceleration

Friction

Moments

Momentum

Circular

Characteristics

Electromagnetic

Optical

Sound

SolarUniverseThermalEfficiency

Resources

Work

Electromagnetism

Induction

Types

Structure

Extras: Electricity, Forces, Waves, Space, Energy, Radioactivity, Links, Terms, Physics

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Electricity Idea map

1

Voltage Energy

Cost

Mains

Charge

Control

Current

Atom

Electron Proton Neutron

Stationary Moving

Electricity Voltage Idea map

Energy Electrons

Circuit

Voltage Current

Components

LDRAmmeter Voltmeter Thermistor

Series Parallel

causes...

1.1

Electricity Voltage Energy and Electrons

• Electricity is fundamentally about 2 things…

• Electrons• Tiny particle• Carry charge• Carry Energy• Effectively Invisible

• Energy• Ability to do• Invisible

Electricity Voltage Current

• Electric Current• Current• Flow of charge• Electricity• Moving Electrons• Symbol I

Mean the same

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

Low Voltage

Electricity Voltage Voltage Idea

High Voltage

• Energy per electron• Voltage• Potential Energy• Potential• Symbol V

Mean the same

Low energy Electron High energy Electron

Electricity Voltage Potential Difference

En

ergy

• Potential Energy Difference between 2 points on a wire

• Potential Difference • P.D.• Difference in Voltage• Voltage across

Mean the same

Electricity Voltage Voltmeter

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

A voltmeter connected across (in parallel with) the component.

V

4 Volts

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• One causes a change in the other• Link• A formula allows us to calculate a value• Dependent

Mean the same

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-voltage graphs are used to show how the…

• Current through a component varies with the voltage across it.

Voltage

Cu

rren

t

Proportional : As one value increasesso does a second value

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

12 V3 A

Electricity Voltage Series Circuit

• 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

3 A3 A

4 Ω

6 V 6 V

2 Ω2 Ω

Electricity Voltage Parallel Circuit

12 V

12 V

3 A2 A

1 A• 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

12 V

3 A

Electricity Voltage Filament Bulb

• The resistance of a filament lamp increases…• As the temperature of the filament increases.

Res

ista

nce

Temperature

Electricity Voltage Diode

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

• The diode has a very high resistance in the reverse direction.

VOLTAGE

CU

RR

EN

T

normal flow

no flow

Electricity Voltage Light Dependent Resistor

• 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…

1000 Ω 10 Ω

Electricity Voltage Thermistor

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

1000 Ω 10 Ω

Electricity Voltage Symbols

V

A

Switch (open) Switch (closed)Cell

Battery

Resistor

Voltmeter

Ammeter

Diode

Variable resistor

Thermistor

L.D.R

Lamp

Fuse

Electricity Energy Ideas map

Voltage

Energy (J) Time (s)

Current

Watt (J per s)Power

1.2 Electrons Coulomb

deliver… in a certain…

to give us…

x

Electricity Energy Electrons carries energy

£2010 J

• 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

• 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.

£30

£20 £10

30 J

20 J 10 J

Bank

Shop Shop

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• 1 Watt = 1 J of energy in 1s

10 J10 J

Power = Current x Potential Difference

P = I x V

10 Watts = 2 Amp x 5 Volt

1km

1km

1km

2 cubic kilometres contain about 6 billion billion grains of salt

1km

1km

1km

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.

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

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

Equals 15 Coulombs

Charge = Current x Time

Q = I x t

15 Coulombs = 3 Amps x 5 seconds

Ability to do

Electrons

Change

Charge per Time

Energy per Charge

Obstacle

Energy per Time

Energy

Charge

Time

Current

Voltage

Resistance

Power

E

Q

t

I

V

R

P

Joule (J)

Coulomb (C)

Second (s)

Amp (A)

Volt (V)

Ohm (Ώ)

Watt (W)

DESCRIPTION NAME SYMBOL UNIT

Electricity Energy Table of 7 key ideas

E Q t

R

V I

P

1 . V = I R

2. E = V Q

3. E = P t

4. Q = I T

5. P = I V

Electricity Energy 7 ideas connected

Electricity Mains Ideas map

Plug Safety

Circuit BreakerLive Fuse

Mains

Types of Current

Direct Alternating

Neutral Earth

1.3

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

Cable grip

Copper Core

Plastic Layer

Plastic Case

Neutral Pin

Fuse

• Brass Pins and Copper Wires are conductors, plastic is an insulator

Live pin

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

• 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.

a.c. d.c.

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

• 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.

12 A

Fuse : 13 A

14 A

Fuse : 13 A

Normal Fault

Electricity Mains Fuse selection

• 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.

3

5

10

13

2

The Goldilocks and the Three

Bears Theory of Fuse Selection™

Melts too soon

Melts too late

Just right

Safe Dangerous

Electricity Mains Circuit Breaker

• 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.

Normal Fault

Safe Current

Weak Magnetic Force

High Current

Strong Magnetic Force

Electricity Mains Earth 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 overloads the fuse.

Earth WireNo Earth Wire

Exposed Wire

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

Force

Electrolysis

Electrons & Protons

Equal

Attraction

Lack of Electrons Extra Electrons

Force

Neutral PositiveNegative

PrinterPhotocopier

Uses

Electricity Charge Balance of Protons and Electrons

+ -+ -

-+

+ -++

+ -+ -

--

+

-

Equal Lack of Electrons Extra Electrons

Neutral PositiveNegative

Electrons

Protons

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

Mean the same

Electricity Charge Multiple Terms

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

Mean the same

• Negatively Charged: Extra Electrons• Positively Charged: Electrons missing

Both Electrically Charged

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

• 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.

-+ +

+

+

++

+

+ +

++++ +

+

+

+

+

+

+- -

-

-

-

-

-

-

-

-

-

-

-

-

-

--

-

--+ +

+

+

++

+

+ +

++++ +

+

+

+

+

+

+- -

-

-

-

-

-

-

-

-

-

-

-

-

-

--

-

-

Positive NegativeNeutral Neutral

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.

A

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

• 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.

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

Electricity Control Ideas Map

1.6

ProcessorLogic Gates

Sensor

Output device

AND, OR, NOT

Potential Divider

Relay

Capacitor

Time Delay

Variable Resistor

Transistor

Switches

Modifiers

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

• Output devices include:

• Lamps and LEDs (light emitting diode) which produce light• Buzzers which produce sound• Motors which produce movement• Heaters which produce heat

M

Electricity Control Variable Resistor

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

PO

TE

NT

IAL

EN

ER

GY

• 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).

Thermistor Variable ResistorV outV in

Electricity Control Potential Divider

0 V

1 V

5 V

4 V

3 V

2 V

0 Ω

1000 Ω

5000 Ω

4000 Ω

3000 Ω

2000 Ω

Electricity Control Equal Resistance

• If the two resistors change by the same amount..• They will continue to share the voltage equally

Vout

0 V

1 V

5 V

4 V

3 V

2 V

0 Ω

1000 Ω

5000 Ω

4000 Ω

3000 Ω

2000 Ω

Electricity Control Unequal Resistance

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

Vout

Forces Idea Map

2 Fie

ld

Acceleration

Co

nta

ct

Forces

Circular

Momentum

Moments

Friction Gravity

MagnetismMuscular

Around PivotUnbalanced 90o to Motion

Graphs

Changing Velocity

No Acceleration

Balanced

Mass

Constant Velocity

Forces Graphs Summary

Time

Stop

Time

Constant Velocity

Stop

Faster Constant Velocity

Constant Velocity Acceleration

Greater Acceleration

2.1 Graphs

Distance Velocity

Dis

tan

ce (

m)

Vel

oci

ty (

m/s

)

Forces Graphs Distance Time

DIS

TA

NC

E

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 lines

• Objects moving with a steady speed are represented by sloping straight lines.

• The steeper the slope of the graph, the greater the speed it represents.

• If an object moves in a straight line, how far it is from a certain point can be represented by a distance-time graph.

Time

Faster Constant Velocity

Constant Velocity

Dis

tan

ce (

m)

Stationary

StationaryConstant Velocity

Faster Constant Velocity

Stationary

Stationary

Forces Graphs Velocity

• The velocity of an object is its speed in a given direction.

Speed: ConstantDirection: Changing

Velocity : Changing

Speed: ConstantDirection: Constant

Velocity : Constant

Forces Graphs Velocity 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..

VE

LO

CIT

Y

TIME TIME TIME

Forces Graphs Acceleration

• 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:

VE

LO

CIT

Y

Time

Velocity Change

TIME

Velocity Change = Acceleration x Time

v - u = a x t

10 m/s = 2 m/s2 x 5 seconds

Forces Graphs Gradient for Speed

• Candidates should be able to calculate the gradient / slope of a distance-time graph.

DIS

TA

NC

E

TIME10

0 km

2 hr

100 km ÷ 2 hr = 50 km/h

Forces Graphs Gradient for Acceleration

• Candidates should be able to calculate:• The gradient of a velocity-time graph and interpret this as acceleration.

VE

LO

CIT

Y

TIME60

m/s

20 sec

60 m/s ÷ 20 sec = 3 m/s2

Forces Graphs Area for Distance

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

VE

LO

CIT

Y

6 m/s

5 secV

EL

OC

ITY

15m

6 m/s

5 sec

30m

Forces Acceleration Ideas Map

Newton

F = maAcceleration

Balanced Unbalanced

Forces

Constant Velocity

eg 0 m/s or 10 m/s eg 2 m/s2 or 9 m/s2

2.2

Forces Acceleration Horizontal

AccelerationSpeedDirection

No??

AccelerationSpeedDirection

Yes??

Forces Acceleration Vertical

AccelerationSpeedDirection

No??

AccelerationSpeedDirection

Yes??

Forces Acceleration Constant Motion

• 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.

STOP

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

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

• The greater the force, the greater the acceleration.

VE

LO

CIT

YV

EL

OC

ITY

VE

LO

CIT

Y

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

1 kg

1 2 300

1

2

3

• 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

Time (sec)

Spe

ed (

m/s

)

Forces Acceleration Falling Objects

4 kg

2 kg1 kg

Forces Acceleration Falling Objects II

Acceleration = Force (Weight) ÷ Mass

a =

40 N

4 kg

=

20 N

2 kg

= 10 N

1 kg

= 10 m/s2

x Gravity (10 N/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.

40 N

4 kg

≠

20 N

2 kg

≠ 1 kg

- 5 N

- 5 N

- 5 N

Forces Acceleration Changing Mass

Masskg

GravityN/kg

WeightN

Distancem

FrictionN

ResultantN

Accelerationm/s2

Times

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

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

0 2 4 6 8 10 12

Forces Acceleration Mass vs Descent Time

Mass (Kg)

Tim

e (s

)

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.

40 N40 N

4 kg

≠ ≠

- 5 N - 10 N

4 kg 4 kg

40 N

- 15 N

Forces Acceleration Changing Friction

Masskg

GravityN/kg

WeightN

Distancem

FrictionN

ResultantN

Accelerationm/s2

Times

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

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

1.50

0 100 200 300 400 500 600

Forces Acceleration Friction vs Descent Time

Friction (N)

Tim

e (s

)

Forces Acceleration Time Formula

s = distance travelled u = initial velocity v = final velocity a = acceleration t = time taken

acceleration = velocity change ÷ time

a = v - u ÷ t1. v = u + at

average speed = distance ÷ time2. (u + v) ÷ 2 = s ÷ t1. into 2. (u + u + at) ÷ 2 = s ÷ t

u is zero so…½at = s ÷ t

s = ½at2

2s ÷ a = t2

t = √(2s ÷ a)

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

Friction2.3Fluids Solid

Air Water

Terminal Velocity

Reaction Braking

Stopping

Brakes

Friction = Weight

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

• 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.

friction

Forces Friction Braking

• 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

TIME

SP

EE

D

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.

long stopping distance

short stopping distance

reaction time

braking time

Forces Friction Stopping Time

• The overall stopping distance is greater if:• The vehicle is initially travelling faster• The driver's reactions are slower (due to tiredness,

drugs, alcohol)• There are adverse weather conditions (wet/icy roads,

poor visibility)• The vehicle is poorly maintained (e.g. worn brakes/tyres)

Stopping time

Spe

ed

• The stopping distance of a vehicle depends on:• The distance the vehicle travels during the

driver's reaction time.• The distance the vehicle travels under the

braking force.

Forces Friction Terminal Velocity

• 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

time

forc

e

weight

friction

60 m/s 4 m/s

acce

lera

tio

n

term

inal

vel

oci

ty

dec

eler

atio

n

on

gro

un

d

term

inal

vel

oci

ty

Forces Friction Terminal Velocity II

Friction

Weight

Friction = Weight therefore there is no acceleration

Forces Friction Driving

• When a vehicle has a steady speed …• The frictional forces balance the driving force.

driving forcefrictional forces

Forces Momentum Ideas Map

2.5

Momentum

Objects have… Velocity

Mass

x

=

Before Collision

After Collision

Before

After

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

• 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).

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

50 Kg m/s

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

50 Kg m/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 Time10 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

5.4Work (J)

Energy (J)

Useful Energy Wasted Energy

Gravity

ElasticMovement against force

Friction

Inertia

Power (J/s)

Calculated by

Energy Work Joule

• Energy is measured in joules (J).

Jam

es P

resc

ott

Jo

ule

(18

18 -

188

9)

1 Newton

1 metre

0.0 J

0.2 J

0.4 J

0.6 J

0.8 J

1.0 J

Energy Work Examples

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

1,000,000,000,000,000 J 10,000,000,000,000 J 100,000,000 J 1,000 J

100 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

Work = Force x Distance

Gravitational Potential Energy = Weight x Change in Height

GPE = W x Δh

50 J = 10 N x 5 m

10 N

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.

WEIGHT

MASS

Energy Work Mass, Gravity and Weight

MASS

GRAVITY FIELD

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 = ½ m x v²

10 J = 0.5 x 5 kg x 4 (m/s)2

Energy Work Power

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

200,000,000 W 500,000 W

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)

800700685545475440400265210125120 083

Activity

playing basketballcycling (21 km/h)climbing stairs (116 steps/min)skating (15 km/h)swimming (1.6 km/h)playing tenniscycling (15 km/h)walking (5 km/h)sitting with attention focusedstanding at restsitting at restsleeping

Radioactivity Ideas Map

6

Uses

Radioactivity

Structure

Atoms

PropertiesTypes

Decay

Radioactivity Types Ideas Map

Gamma

Beta

Alpha

6.1

Uses

Types

Tracer

Measuring

Sterilisation

SourceBackground

SpecificRadioactivity

Half Life

Speed of Decay

Radioactivity Types Atoms

• Iron on Copper The Kanji characters for "atom."

• Every thing is made of atoms

Radioactivity Types Stable vs Unstable

• There are two kinds of atoms…

Stable Unstable: Will emit radiation randomly once

Radioactivity Types Alpha Beta Gamma

PA

PE

R

ALU

MIN

IUM

LEA

D

ALPHA

BETA

GAMMA

2 Protons2 Neutrons

High EnergyElectron

High Frequency Wave

• Unstable atoms emit 3 types of radiation…

Radioactivity Types Sources

• 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. • The radiation from all these sources is called background radiation.

carpets

loft insulation

Radioactivity Types Ions

• When radiation from radioactive materials collides with neutral 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.

-1

+1+ 1

-1

+1+ 1

-1

Normal Atom Ion

Radioactivity Types Ionising Radiation

• 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

ALPHA

BETA

GAMMA

most dangerous

leastdangerous

most dangerous

leastdangerous

Used as tracer

Radioactivity Types Monitoring Dosage

• Workers who are at risk from radiation often wear a radiation badge to 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.

Low Dosage High Dosage

Radioactivity Types Half Life

• 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.

100

50

0

0 14 28

Time (s)

Un

dec

ayed

Ato

ms

Radioactivity Structure Ideas Map

6.2

DatingElement

Fission

Atomic Structure

Isotope

Discovery

Scattering Exp.

Nucleus

Nucleons

Proton Neutron Electron

Type of atom

Radioactivity Structure Relative Size

• 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.

ProtonNeutron Electron

Radioactivity Structure Rutherford Expectation

Lo

rd E

rnes

t R

uth

erfo

rd (

1871

- 1

937)

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

gold leafalpha particle source alpha detectors

What they expected….

Radioactivity Structure Rutherford Result

deflection

• What actually happened….

• Conclusion 1 : The plum pudding model must be wrong

straight through

reflected back

Radioactivity Structure Rutherford Conclusion

++

++

• Conclusion 2 : Nuclei are positive and far apart

++

++

++

simplified gold nucleus

Radioactivity Structure Masses

Neutron

Electron

• 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

Radioactivity Structure Notation

• 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.

Ne+ = 20

= 10

Radioactivity Structure Proton Number

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

3 protons therefore Lithium

Radioactivity Structure Elements

• Atoms of different elements have different numbers of protons.

1 proton therefore Hydrogen 2 protons therefore

Helium

3 protons therefore Lithium 4 protons therefore

Berylium

Radioactivity Structure Isotopes

• Atoms of the same element which have different numbers of neutrons are called isotopes.

normalHydrogen 1 extra

neutron

2 extraneutrons 3 extra

neutrons

isotopes of hydrogen

Radioactivity Structure Beta Decay

• Radioactive isotopes (radioisotopes or radionuclides) are atoms with unstable nuclei. When an unstable nucleus splits up (disintegrates):

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

Radioactivity Structure Fission

• 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

• 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.

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

Radioactivity Structure Carbon Dating

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

The tomb of Rameses IX lies in the centre of the Valley of

the Kings

Wooden Bowl dated to 1000 BC

Radioactivity Structure Carbon Dating

• 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.

5,000yr 10,000yr

74%

100%

1,00

0yr

Radioactivity Structure Non-Carbon Dating

58%

15,0

00 y

r

42%

• Uranium isotopes, which have a very long half-life, decay via a series of relatively short-lived radioisotopes to produce stable isotopes of lead.

• 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

ELECTRICITYAlternating currentAmmeterAmpereAnodeBatteryCapacitorCathodeCellChargeCircuit breakerConductorCoreCoulombCurrentDiodeDirect currentDynamoEarthingElectrical energyElectrical chargeElectric currentElectrodeElectrolysisElectrolyteElectromagnetElectromagnetic inductionElectronElectrostatic forcesFree electronFrictionFuseGeneratorHertzInput sensorInsulationInsulatorIonIoniseJouleKilowattKilowatt hourLight-dependent resistorLogic gateMagnetMagnetic fieldMotor effectOhmOutput deviceParallel/series circuitsPotential differencePotential dividerPowerPrimary coilProcessorRelayResistance

FORCEAccelerationAir resistanceBraking distanceCentre of massCentripetal forceDecelerateDragElastic collisionFrictionGravityKinetic energyMassMomentMomentumNewtonPivotSpeedTerminal velocityThinking distance VelocityWeight

WAVESAmplitudeAnalogue signalCompression Converging lensCoreCrestsCritical engleCrustCycleDiffractionDigital signalsDiverging lensElectromagnetic spectrumElectromagnetic wavesFetal imaging FetusFocusFrequencyHertzLithosphereLongitudinal waveMagmaMantleNormalP wavesRarefractionReal imageRefractionSeismic wavesSeismographS wavesSubduction zoneTectonic platesTotal internal reflectionTransverse wavesTroughsUltrasoundVibrationVirtual imageWavelengthWavesWave speed

SPACEArtificial satelliteBig bangBlack holeCometFusionGalaxyGeostationary satelliteGravityLight yearMilky wayMoon OrbitPlanetRed planetRed giantRed shiftSatelliteSolar systemStarSunUniverseWhite dwarf

ENERGYConductionConvectionEfficiencyElastic potential energyElectrical energyFossil fuelsFree electronsGeneratorGeothermal energyGlobal warmingGravitational potential energyGreenhouse effectHydroelectricKinetic energyNon-renewable resourcesPowerRadiationRenewable energyTurbineWork

RADIOACTIVITYActivityAlphaAtomAtomic numberBackground radiationBetaChain reactionCosmic rayCount rateDecayElectronsElectromagnetic spectrumElement GammaGieger-Muller tubeHalf-lifeIoniseIsotopeMass numberNeutronNuclear fissionNucleonNucleusProtonRadiationRadioactive datingRadioactive decayRadioactive emissionsRadioactive tracerRadioactivityRadioisotopesRandom

ResistorSecondary coilSolenoidThermistorTransformerTransistorVoltVoltageVoltmeterWatt

Connections

SeismicTectonic

PHYSICS

Electricity

Forces

Waves

Radioactivity

SpaceEnergy

Voltage

Energy

Mains

Cost

Charge

Control

GraphsAcceleration

Friction

MomentsMomentum

Circular

Characteristics

Electromagnetic Spectrum

Optical

SoundSolar

Universe

Thermal

Efficiency

Resources

Work

Electromagnetism

Induction

Types

Structure

Amplitude

Analogue signal

Compression

Core

Critical angle

Crests

Converging lens

Crust

Digital signals

Diverging lens

Diffraction

Cycle

Focus

Frequency

Fetal imaging

Hertz

Lithosphere

Magma

P waves

Refraction

Mantle

Rarefraction

Normal

Longitudinal

Subduction zone

Total internal reflection

Seismograph

S waves

Real image

Transverse

Troughs

Vibration

Virtual image

Wave speed

Wavelength

Ultrasound

Air resistance

Braking distance

Centre of mass

Centripetal force

Decelerate

Drag

Pivot

Speed

Terminal velocity

Thinking distance

VelocityWeight

Elastic collision

Gravity

Kinetic energy

MassNewton

Artificial satelliteLight year

Big bang

Milky way

Black holeOrbit

Moon

Comet

Planets

FusionRed giant

GalaxyRed shift

GeostationaryPolar

SatelliteStar

Solar system

Sun

White dwarf

Conduction Convection

Elastic potential energy

Electrical energy

Fossil fuels

Generator

Geothermal

Stopping Distance

Direction

HertzInsulation

Input sensor

Insulator

Joule

Kilowatt

Kilowatt hour

Light-dependent resistorLogic gate

Output device

Ohm

Circuits

Potential difference

Potential divider

Power

Processor

RelayResistor

Resistance

Thermistor

Transistor

VoltVoltage

Watt

Voltmeter

Alpha

Atom

Atomic number

Background radiation

Beta

Chain reaction

Cosmic ray

Count rate

Nuclear fission

Nucleon

Nucleus

Proton

Dating

DecayEmissions

Tracer

Electrons

Electromagnetic spectrum

Element

Gamma

Gieger-Muller tube

Half-life

Isotope

Mass number

Neutron

Radioisotopes

Random

Global warming

Gravitational potential energy

Hydroelectric

Greenhouse effect

Kinetic energy

Non-renewable

Power

Renewable Radiation

Turbine

Uses

Magnet

Magnetic field

Motor effect

Primary coil

Secondary coil

Solenoid

Transformer

ATOM small unit of matter

ELECTRON part of atom, can leave

MEASUREMENT what units are used to count electrons

COULOMB a word for a large number of electrons

ABILITY TO MAKE THINGS MOVE charge, there are two types. negative and positive

MOVING ELECTRONS current, flow of charge, electricity

WORDS FOR LARGE NUMBERS are convenient eg the word ‘year’ instead of 31,536,000 seconds

PROPERTIES what features or attributes does an electron have

EFFECTS things that happen because of electrons

STATIONARY ELECTRONS very large numbers of electrons grouped together. static electricity, ’static’, electrostatics

REPELLED move away from other electrons

PROTON part of atom, cannot leave

ATTRACTED move towards protons

EXTRA ELECTRONS negatively charged

ELECTRONS HAVE A NEGATIVE CHARGE sometimes electrons are referred to as ‘charge’.The charge on proton is positive LACK OF ELECTRONS

positively charged

MEASUREMENThow many electrons passing a point

ENERGY electrons can deliver energy

ELECTRONS PER SECONDmeasured in amps

ENERGY DELIVERED PER SECOND measured in watts, joules per second

ENERGY PER ELECTRON measured in volts

- - +-

EASE OF MOVEMENTTYPES OF MOVEMENT

BACKWARDS AND FORWARDS alternating current

ALWAYS ONE WAY direct current

MAINS delivers energy to the home

BATTERY

EASY conductor eg copper

DIFFICULT SOMETIMES DIFFICULT

IMPOSSIBLEinsulator eg plastic

EXCESSIVE ENERGY IS DANGEROUS

DIFFICULTY SET BY USER variable resistor

WHEN COLD thermistor

WHEN DARK light dependent resistor

ENERGY COSTS MONEY

IF 1000 JOULES of energy is delivered per second…

…for 1 HOUR

..the electricity company call it a UNIT or kilowatthour…a unit costs about £0.08

SAFETY MEASURES

INDIRECT CONTROL

DELIBERATE WEAK POINT

AUTOMATIC OFF SWITCH

RELAY a small safe current switches on a big unsafe current

FUSEwhen the current surges a thin section of wire melts

CIRCUIT BREAKER very quick off switch

NORMAL NUMBER OF ELECTRONS no charge, neutral

-+++

- - - - -+++

- -+++

1. Charged objects attract neutral ones2. Positive and negative objects attract3. Like charged objects repel

1. Electrons move round circuits 2. A circuit is a number of components eg bulbs connected by wires3. A battery provides a stream of electrons

WIRE IS THIN

WIRE IS LONG

POOR CONDUCTORfixed resistor

Env

ironm

ent

Dep

ende

nt

-

ELECTRICITY phenomena explained by electrons

SPEED m/s

DISTANCE metres

TIME seconds

DIRECTION

SIZE measured in newtons

EXAMPLES

INCREASE acceleration

DECREASE deceleration

CONSTANT SPEED

D

T

S

T

CHANGING SPEED CHANGING DIRECTION

TEMPORARY FORCE direction changes

CONSTANT FORCE direction always changes

Circular eg ball swung round on a string moon orbiting earth

OBJECTS HAVE...

FORCES ACTING ON THEMBALANCED FORCES

UNBALANCED FORCES

CONSTANT VELOCITY eg 0 m/s or 100 m/s

CHANGING VELOCITY

CHARACTERISTICS how can we describe a force

DIRECTION

CONTACT FORCES muscular, friction

NONCONTACT FORCES field forces. gravity, magnetism

GRAPHS representing motion

CHANGING SPEED

D

T

S

T

VELOCITY

sober, well rested, good brakes, dry road

drunk, tired, bad brakes, icy road

stop

stop

braking

braking

weight

friction

Friction = WeightAcceleration = 0Speed = 60 m/s

Terminal Velocity

Momentum

Mass

FORCE AND MOTION a push or a pull which creates movement

TYPES OF MOVEMENT

OSCILLATION also known as vibration

A to BSIDE TO SIDE UP AND DOWN

KNOCK-ON EFFECTS original movement causes movement elsewhere

WAVES

CHARACTERISTICS how do we describe waves

BEHAVIOUR what do waves do

TYPES

How big is the oscillation?The AMPLITUDE is 2 metres

How long is the wave from peak to peak?The WAVELENGTH is 5 metres

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

How fast is the wave travelling?The SPEED of the wave is 10 metres per second

CHANGE SPEED eg moving from air to glass

CHANGE DIRECTION

SPREAD OUT when passing thru a gap: diffraction

OSCILLATION AT 90O

TO DIRECTION OFTRAVELtransverse waves

OSCILLATION IN DIRECTION OFTRAVEL longitundinal waves

Sound SLINKY

EARTHQUAKES

ROPE SEA WAVES ELECTROMAGNETIC300,000 km/s

CAN CARRY INFORMATION analogue or digital

BENDINGlight refracts when it hits glass at an angle

BOUNCING OFF reflection

BENT TOWARDS each other by a convex lens

BENT AWAY FROM each other by a concave lens

MANY PARALLEL WAVES

ISOLATED original movement only

GAMMA X RAY ULTRAVIOLET LIGHT INFRARED MICROWAVE RADIO

SINGLE WAVE

AM

PLI

TU

DE

WAVELENGTH

digital is better because the message is preserved even if the wave is distorted

distorted wave still readable as 1 or 0

WAVES movement of energy but not matter

HISTORY

UNIVERSEeverything we can see

STRUCTURE

OUR GALAXY100 billion stars called the milky way

OTHER GALAXIES100 billion

OUR STAR, THE SUNis orbited by..

8 OTHER PLANETS

Mercury, Venus, (Earth), Mars, Jupiter, Saturn, Uranus, Neptune, Pluto

THE EARTHis orbited by..

SATELLITESobjects held in circular path by earth’s gravity

NATURAL ARTIFICAIL

MOONcauses tides

USES

MONITOR EARTHweather, military

COMMUNICATIONSMONITOR SPACEeg hubble space telescope

TYPES OF ORBIT

APPARENTLY FIXED IN THE SKYgeostationary orbit

MOVES IN THE SKYpolar orbit

STARSmassive nuclear furnaces

ENERGY SOURCE LIFE CYCLE

NUCLEAR FUSIONhydrogen and helium fusing together to create..

HEAT AND LIGHT

HEAVIER ATOMS which make life possibleeg carbon

PASTgravity pulls dust together. fusion begins

PRESENTexpansive nuclear forces = gravity

FUTURE

MEDIUM STAR BIG STAR VERY BIG STAR

STAR SWELLSinto a red giant

STAR EXPLODESsupernova

BLACK HOLE ultra dense, no light escapes

expansive forces win over gravity

PAST PRESENT FUTURE

MASSIVEEXPLOSIONBig Bang

EXPANDING

EVIDENCE FOR EXPANSION

RED SHIFTlight from distance stars has a longer wavelength than we would ‘expect’ if universe were static

CONTRACTION?Big Crunch?

LIFEEvidence for

DIRECT INDIRECT

Chemical changes in atmosphere Eg O2

Finding live or fossilised organisms

Broadcast signals

SPACE universe, galaxy, solar system, star, planet, satellite

ENERGY

CHARACTERISTICS

CANNOT BE DESTROYED

TYPES

POTENTIAL ENERGY stored energy KINETIC ENERGY movement energy

SMALL SCALE can’t seeLARGE SCALE can see SMALL SCALE can’t seeLARGE SCALE can see

BONDS BETWEEN ATOMS chemical

UNSTABLE ATOMS nuclear

MATERIAL UNDER TENSION strain

HEIGHT gravitational potential energy

ATOMS VIBRATING heat or thermal energy

MOVING CAR

ENERGY USEFUL TO HUMANS known as work eg a moving car

maximising the useful energy makes the car EFFICIENT

eg coal, gas, oil, wood

eg water behind dam, sky diver

MEASURED in joules

1. ATOMS COLLIDE WITH THEIR NEIGHBOURS conduction

3. WAVE TRANSMISSION radiation

2. ATOMS MOVE TO A NEW LOCATION convection

VIBRATIONS CAN SPREAD IN 3 WAYS

eg uraniumeg bow and arrow, spring

CANNOT BE CREATED

ENERGY CAN CHANGE TYPErate of change is measured in watts

STORED ENERGY eg petrol is changed into…

ENERGY NOT USEFUL TO HUMANS known as dissipated energy eg heat from car engine

CURRENT CREATES MOVEMENT motor

MOVEMENT CREATES CURRENT generator

ROTATIONof magnet

ELECTRONS FLOWING magnetic field created

F

D

F

D F

D

GREATER FORCE means greater energy

GREATER DISTANCE means greater energy

eg saucepan base

eg warmth from sun

eg boiling water

NS NS N SN S

MAGNET MOVING WIRE MOVING

Creating current without contact (Induction)

ENERGY the ability to make things happen

STRUCTUREwhat is an atom made of

UNSTABLE ATOMSbreak apart, pop, decay RANDOMLYby kicking out (emitting) particles and energy

STABLE ATOMS stay the same forever

ATOMsmall unit of matter

CENTRAL COREnucleus

.

.NUCLEONvery small unit of matter

PROTON

positively charged(exerts a force)

NEUTRON

not charged(exerts no force)

OUTER CLOUD

.ELECTRONsmallest unit of matternegatively charged(exerts a force)

HYDROGEN ATOMSalways have one proton

HELIUM ATOMSalways have two protons

a LITHIUM ATOMalways has three protons

normal atom

isotopes have extra neutrons

proton number

mass number

TYPES OF ATOM elements

STABILITY OF ATOM

2 PROTONS & 2 NEUTRONS EMITTEDalpha radiation

1 ELECTRONEMITTEDbeta radiation

.

HIGH ENERGY WAVE EMITTEDgamma radiation

WHAT ATOMS EMIT

BLOCKED BY(absorbed by)

card

alum

iniu

m

lead

FORMATION

NATURAL

UNNATURAL

bombarded with neutrons

CONTROLLEDnuclear reactor

RAPIDnuclear bomb

HOW UNSTABLE IS THE ATOM?how long does it take for…

Li7

3chemical symbol

ALL ATOMS TO DECAY

HALF THE ATOMS TO DECAY

DIFFICULT TO PREDICT

EASY TOPREDICT

VERY UNSTABLEshort halflife

50%

1ms

VERYSTABLElong halflife

50%

1mil. yr.

DESCRIPTION AND NOTATION

alpha

beta

gamma

alpha

beta

gamma

INS

IDE

BO

DY

skin cell: dead

tissue cell: live

damaged cell

OU

TS

IDE

BO

DY

MEDICAL USE

98%

1%1%

protons inatoms

protons in alpha particleslike charges repel

Rutherford used alpha particle to show that nuclei are far apart

RADIOACTIVITY fast moving particles and high energy waves

Frequency (f) Wavelength (λ)

Gravitational Field Strength (g)

Weight (w)

Change in Height (Δh)

Distance (d)

Force (F)

Acceleration (a)

Power (P)

Charge (Q)Resistance (R)

Time (t)

Voltage (V)

Current (I)

Energy (E)

ELECTRICAL

Unit Cost

Total Cost

Efficiency

Useful Energy

Momentum

Mass (m) Velocity (v)

ELECTRICALWORKKINETICGPE

Moment

Impulse

½ mv2

Links