AQA Additional Science

AQA Additional Science
23/04/2017 AQA Additional Science Physics 2 A slideshow that covers the entire AQA 2006 Syllabus Physics 2 Module W Richards

Distance, Speed and Time
23/04/2017 Distance, Speed and Time D T S Speed = distance (in metres) time (in seconds) Seb walks 200 metres in 40 seconds. What is his speed? Lucy covers 2km in 1,000 seconds. What is her speed? How long would it take Freddie to run 100 metres if he runs at 10m/s? Sue travels at 50m/s for 20s. How far does he go? Hannah drives her car at 85mph (about 40m/s). How long does it take her to drive 20km?

Speed vs. Velocity Speed is simply how fast you are travelling…
23/04/2017 Speed is simply how fast you are travelling… This car is travelling at a speed of 20m/s Velocity is “speed in a given direction” (a “vector quantity”)… This car is travelling at a velocity of 20m/s east

Acceleration V-U T A Acceleration = change in velocity (in m/s)
23/04/2017 V-U T A Acceleration Acceleration = change in velocity (in m/s) (in m/s2) time taken (in s) A cyclist accelerates from 0 to 10m/s in 5 seconds. What is her acceleration? A ball is dropped and accelerates downwards at a rate of 10m/s2 for 12 seconds. How much will the ball’s velocity increase by? A car accelerates from 10 to 20m/s with an acceleration of 2m/s2. How long did this take? A rocket accelerates from 1,000m/s to 5,000m/s in 2 seconds. What is its acceleration?

Velocity-time graphs 1) Upwards line = 80 60 40 20 4) Downward line =
23/04/2017 1) Upwards line = 80 60 40 20 4) Downward line = Velocity m/s 3) Upwards line = 2) Horizontal line = T/s

80 60 40 20 23/04/2017 Velocity m/s T/s How fast was the object going after 10 seconds? What is the acceleration from 20 to 30 seconds? What was the deceleration from 30 to 50s? How far did the object travel altogether?

Balanced and unbalanced forces
23/04/2017 Reaction Consider a camel standing on a road. What forces are acting on it? These two forces would be equal – we say that they are BALANCED. The camel doesn’t move anywhere. Weight

23/04/2017 Reaction What would happen if we took the road away? The camel’s weight is no longer balanced by anything, so the camel falls downwards… Weight

Introduction to Forces
23/04/2017 A force is a “push” or a “pull”. Some common examples: Air resistance/drag – a contact force that acts against anything moving through air or liquid Weight (mg) – pulls things towards the centre of the Earth _____ – a contact force that acts against anything moving Upthrust – keeps things afloat

Air Resistance 23/04/2017 Air resistance is a force that opposes motion through air. The quicker you travel, the bigger the air resistance: The same applies to a body falling through a liquid (called “drag” or “upthrust”).

23/04/2017

23/04/2017 1) This animal is either ________ or moving with _____ _____… 2) This animal is getting _________… 3) This animal is getting _______…. 4) This animal is…

Resultant Force Calculate the resultant force of the following: 500N
23/04/2017 Calculate the resultant force of the following: 500N 100N 700N 600N 50N 700N 700N 800N 800N 200N 100N

Force and acceleration
23/04/2017 If the forces acting on an object are unbalanced then the object will accelerate, like these wrestlers: Force (in N) = Mass (in kg) x Acceleration (in m/s2) F A M

Force, mass and acceleration
23/04/2017 A force of 1000N is applied to push a mass of 500kg. How quickly does it accelerate? A force of 3000N acts on a car to make it accelerate by 1.5m/s2. How heavy is the car? A car accelerates at a rate of 5m/s2. If it weighs 500kg how much driving force is the engine applying? A force of 10N is applied by a boy while lifting a 20kg mass. How much does it accelerate by? F A M

Words – increase, small, constant, balance, accelerates
Terminal Velocity 23/04/2017 Consider a skydiver: At the start of his jump the air resistance is _______ so he _______ downwards. 2) As his speed increases his air resistance will _______ 3) Eventually the air resistance will be big enough to _______ the skydiver’s weight. At this point the forces are balanced so his speed becomes ________ - this is called TERMINAL VELOCITY Words – increase, small, constant, balance, accelerates

Words – slowing down, decrease, increases, terminal velocity, weight
23/04/2017 Consider a skydiver: 4) When he opens his parachute the air resistance suddenly ________, causing him to start _____ ____. 5) Because he is slowing down his air resistance will _______ again until it balances his _________. The skydiver has now reached a new, lower ________ _______. Words – slowing down, decrease, increases, terminal velocity, weight

Velocity-time graph for terminal velocity…
23/04/2017 Parachute opens – diver slows down Velocity Speed increases… Terminal velocity reached… On the Moon Diver hits the ground New, lower terminal velocity reached Time

Stopping a car… Tiredness Too much alcohol Too many drugs
23/04/2017 Tiredness Too much alcohol Thinking distance (reaction time) Too many drugs Poor visibility Wet roads Icy roads Braking distance Tyres/brakes worn out Driving too fast

Momentum 23/04/2017 Any object that has both mass and velocity has MOMENTUM. Momentum (symbol “p”) is simply given by the formula: P V M Momentum = Mass x Velocity (in kgms-1) (in kg) (in ms-1) What is the momentum of the following? A 1kg football travelling at 10ms-1 A 1000kg Ford Capri travelling at 30ms-1 A 20g pen being thrown across the room at 5ms-1 A 70kg bungi-jumper falling at 40ms-1

Force and momentum mv T F
23/04/2017 Newton’s second law of motion says that the force acting on an object is that object’s rate of change of momentum. In other words… mv T F Force = Change in momentum Time (in N) (in kgm/s) (in s) Also called “impulse” For example, David Beckham takes a free kick by kicking a stationary football with a force of 40N. If the ball has a mass of 0.5kg and his foot is in contact with the ball for 0.1s calculate: The change in momentum of the ball (its impulse), The speed the ball moves away with

Example questions 23/04/2017 Ben likes playing golf. He strikes a golf ball with a force of 80N. If the ball has a mass of 200g and the club is in contact with it for 0.2s calculate a) the change in momentum of the golf ball, b) its speed. Nick thinks it’s funny to hit tennis balls at Tom. He strikes a serve with a force of 30N. If the ball has a mass of 250g and the racket is in contact with it for 0.15s calculate the ball’s change in momentum and its speed. Dan takes a dropkick by kicking a 0.4kg rugby ball away at 10m/s. If his foot was in contact with the ball for 0.1 seconds calculate the force he applied to the ball. Simon strikes a 200g golf ball away at 50m/s. If he applied a force of 50N calculate how long his club was in contact with the ball for.

Safety features 23/04/2017 Let’s use Newton’s Second Law to explain how airbags work: mv T F Basically: The change in momentum is the same with or without an airbag But having an airbag increases the time of the collision Therefore the force is reduced

Weight vs. Mass 23/04/2017 Earth’s Gravitational Field Strength is 10N/kg. In other words, a 1kg mass is pulled downwards by a force of 10N. W g M Weight = Mass x Gravitational Field Strength (in N) (in kg) (in N/kg) What is the weight on Earth of a book with mass 2kg? What is the weight on Earth of an apple with mass 100g? Dave weighs 700N. What is his mass? On the moon the gravitational field strength is 1.6N/kg. What will Dave weigh if he stands on the moon?

Stopping a car… Tiredness Too much alcohol Too many drugs
23/04/2017 Tiredness Too much alcohol Thinking distance (reaction time) Too many drugs Poor visibility Wet roads Icy roads Braking distance Tyres/brakes worn out Driving too fast

Work done = Force x distance moved
23/04/2017 When any object is moved around work will need to be done on it to get it to move (obviously). We can work out the amount of work done in moving an object using the formula: Work done = Force x distance moved in J in N in m W D F

Example questions 23/04/2017 Bori pushes a book 5m along the table with a force of 5N. He gets tired and decides to call it a day. How much work did he do? Alicia lifts a laptop 2m into the air with a force of 10N. How much work does she do? Martin does 200J of work by pushing a wheelbarrow with a force of 50N. How far did he push it? Chris cuddles his cat and lifts it 1.5m in the air. If he did 75J of work how much force did he use? Carl drives his car 1000m. If the engine was producing a driving force of 2000N how much work did the car do?

Elastic Potential Energy
23/04/2017 Elastic potential energy is the energy stored in a system when work is done to change its shape, e.g:

Kinetic energy = ½ x mass x velocity squared
23/04/2017 Any object that moves will have kinetic energy. The amount of kinetic energy an object has can be found using the formula: Kinetic energy = ½ x mass x velocity squared in J in kg in m/s KE = ½ mv2

Example questions 23/04/2017 Nicole drives her car at a speed of 30m/s. If the combined mass of her and the car is 1000kg what is her kinetic energy? Shanie rides her bike at a speed of 10m/s. If the combined mass of Shanie and her bike is 80kg what is her kinetic energy? Dan is running and has a kinetic energy of 750J. If his mass is 60kg how fast is he running? George is walking to town. If he has a kinetic energy of 150J and he’s walking at a pace of 2m/s what is his mass?

Random questions… 23/04/2017 Sophie tries to run 100m in 12 seconds and succeeds. How fast did she run? Tommy accelerates at a rate of 2m/s2 for 3 seconds. If he started at 10m/s what was his final speed? Charlie decides to lift his book up into the air. His book has a mass of 100g and he lifts it 50cm. Calculate the work done. Lewis accelerates from 0 to 10m/s in 5 seconds. If his mass is 70kg how much force did his legs apply? Rachel rides 1km at a speed of 20m/s. How long did the journey take? Claire thinks it’s funny to push James with a force of 120N. If James has a mass of 60kg calculate his acceleration. Lauren slams on the brakes on her bike and her brakes do 20,000J of work. If the combined mass is 100kg what speed was she travelling at? Tom has a mass of 75kg. If he accelerates from 10 to 20m/s in 2s how much force did he apply?

Random questions… 23/04/2017 Georgina amuses herself by throwing things at Sarah. If she throws a ball with a speed of 20m/s and the distance between her and Sarah is 5m how long will it take to reach her? Mr Richards throws calculators around the room with a force of 20N. If each calculator has a mass of 200g calculate the acceleration. Sam has a mass of 70kg. What is his weight on Earth, where the gravitational field strength is 10N/kg? Zak does some work by pushing a box around with a force of 1N. He does 5J of work and decides to call it a day. How far did he push it? On the moon Matt might weigh 112N. If the gravitational field strength on the moon is 1.6N/kg what is his mass? What will he weigh on Earth? Dan likes bird watching. He sees a bird fly 100m in 20s. How fast was it flying? How much kinetic energy would Richard have if he travelled at a speed of 5m/s and has a mass of 70kg?

Momentum 23/04/2017 Any object that has both mass and velocity has MOMENTUM. Momentum (symbol “p”) is simply given by the formula: P V M Momentum = Mass x Velocity (in kgms-1) (in kg) (in ms-1) What is the momentum of the following? A 1kg football travelling at 10ms-1 A 1000kg Ford Capri travelling at 30ms-1 A 20g pen being thrown across the room at 5ms-1 A 70kg bungi-jumper falling at 40ms-1

Conservation of Momentum
23/04/2017 In any collision or explosion momentum is conserved (provided that there are no external forces have an effect). Example question: Two cars are racing around the M25. Car A collides with the back of car B and the cars stick together. What speed do they move at after the collision? Speed = 50ms-1 Speed = 20ms-1 Mass = 1000kg Mass = 800kg Speed = ??ms-1 Mass = 1800kg Momentum before = momentum after… …so 1000 x x 20 = 1800 x V… …V = 36.7ms-1

Momentum in different directions
23/04/2017 What happens if the bodies are moving in opposite directions? Speed = 50ms-1 Mass = 1000kg Speed = 20ms-1 Mass = 800kg Momentum is a VECTOR quantity, so the momentum of the second car is negative… Total momentum = 1000 x 50 – 800 x 20 = kgms-1 Speed after collision = kgms-1 / 1800 = 18.9ms-1

Another example 23/04/2017 Consider the nuclear decay of Americium-241: α 4 2 Np 237 93 Am 241 95 If the new neptunium atom moves away at a speed of 5x105 ms-1 what was the speed of the alpha particle?

More questions… 23/04/2017 A white snooker ball moving at 5m/s strikes a red ball and pots it. Both balls have a mass of 1kg. If the white ball continued in the same direction at 2m/s what was the velocity of the red ball? A car of mass 1000kg heading up the M1 at 50m/s collides with a stationary truck of mass 8000kg and sticks to it. What velocity does the wreckage move forward at? A defender running away from a goalkeeper at 5m/s is hit in the back of his head by the goal kick. The ball stops dead and the player’s speed increases to 5.5m/s. If the ball had a mass of 500g and the player had a mass of 70kg how fast was the ball moving? A gun has a recoil speed of 2m/s when firing. If the gun has a mass of 2kg and the bullet has a mass of 10g what speed does the bullet come out at?

Force and momentum mv T F
23/04/2017 Newton’s second law of motion says that the force acting on an object is that object’s rate of change of momentum. In other words… mv T F Force = Change in momentum Time (in N) (in kgm/s) (in s) Also called “impulse” For example, David Beckham takes a free kick by kicking a stationary football with a force of 40N. If the ball has a mass of 0.5kg and his foot is in contact with the ball for 0.1s calculate: The change in momentum of the ball (its impulse), The speed the ball moves away with

Example questions 23/04/2017 Ben likes playing golf. He strikes a golf ball with a force of 80N. If the ball has a mass of 200g and the club is in contact with it for 0.2s calculate a) the change in momentum of the golf ball, b) its speed. Nick thinks it’s funny to hit tennis balls at Tom. He strikes a serve with a force of 30N. If the ball has a mass of 250g and the racket is in contact with it for 0.15s calculate the ball’s change in momentum and its speed. Dan takes a dropkick by kicking a 0.4kg rugby ball away at 10m/s. If his foot was in contact with the ball for 0.1 seconds calculate the force he applied to the ball. Simon strikes a 200g golf ball away at 50m/s. If he applied a force of 50N calculate how long his club was in contact with the ball for.

Safety features 23/04/2017 Let’s use Newton’s Second Law to explain how airbags work: mv T F Basically: The change in momentum is the same with or without an airbag But having an airbag increases the time of the collision Therefore the force is reduced

Static Electricity + + - - + - + + + - - - + + - + - -
23/04/2017 Static electricity is when charge “builds up” on an object and then stays “static”. How the charge builds up depends on what materials are used: + + - - + - + + + - - - + + - + - -

Static Electricity 23/04/2017 + - - -

Van de Graaf generators
23/04/2017

Uses of Static – Smoke Precipitators
23/04/2017 Chimney Negatively charged plates - - - - - - Positively charged grid + + +

Uses and dangers of Static Electricity
23/04/2017 Find out how static electricity is used in the following: 1) Photocopiers 2) Paint sprayer Find out how static electricity is dangerous in the following situations: 1) Fuel pipes 2) Hospitals

Circuit Symbols Variable resistor Diode Switch Bulb A V Ammeter
23/04/2017 Variable resistor Diode Switch Bulb A V Ammeter Voltmeter LDR Resistor Cell Fuse Thermistor Battery

By definition, current is “the rate of flow of charge”
Electric Current 23/04/2017 Electric current is a flow of negatively charged particles (i.e. electrons). Note that electrons go from negative to positive - + e- By definition, current is “the rate of flow of charge” e-

Words: volts, amps, ohms, voltage, ammeter, voltmeter
Basic ideas… 23/04/2017 Electric current is when electrons start to flow around a circuit. We use an _________ to measure it and it is measured in ____. Potential difference (also called _______) is how big the push on the electrons is. We use a ________ to measure it and it is measured in ______, a unit named after Volta. Resistance is anything that resists an electric current. It is measured in _____. Words: volts, amps, ohms, voltage, ammeter, voltmeter

More basic ideas… 23/04/2017 If a battery is added the current will ________ because there is a greater _____ on the electrons If a bulb is added the current will _______ because there is greater ________ in the circuit

Current in a series circuit
23/04/2017 If the current here is 2 amps… The current here will be… The current here will be… And the current here will be… In other words, the current in a series circuit is THE SAME at any point

Current in a parallel circuit
23/04/2017 A PARALLEL circuit is one where the current has a “choice of routes” Here comes the current… Half of the current will go down here (assuming the bulbs are the same)… And the rest will go down here…

Current in a parallel circuit
23/04/2017 If the current here is 6 amps And the current here will be… The current here will be… The current here will be… The current here will be…

Some example questions…
23/04/2017 3A 6A

Voltage in a series circuit
23/04/2017 If the voltage across the battery is 6V… V …and these bulbs are all identical… V V …what will the voltage across each bulb be? 2V

Voltage in a series circuit
23/04/2017 If the voltage across the battery is 6V… V V …what will the voltage across two bulbs be? 4V

Voltage in a parallel circuit
23/04/2017 If the voltage across the batteries is 4V… What is the voltage here? V 4V And here? V 4V

Summary Current is THE SAME at any point
23/04/2017 In a SERIES circuit: Current is THE SAME at any point Voltage SPLITS UP over each component In a PARALLEL circuit: Current SPLITS UP down each “strand” Voltage is THE SAME across each”strand”

An example question: 23/04/2017 6V A3 3A A1 V1 A2 V2 V3

Another example question:
23/04/2017 10V A3 3A A1 V1 A2 V2 V3

Resistance V R I Resistance = Voltage (in V) (in ) Current (in A)
Georg Simon Ohm 23/04/2017 Resistance is anything that will RESIST a current. It is measured in Ohms, a unit named after me. The resistance of a component can be calculated using Ohm’s Law: V R I Resistance = Voltage (in V) (in ) Current (in A)

An example question: Ammeter reads 2A A V
23/04/2017 Ammeter reads 2A V A What is the resistance across this bulb? Assuming all the bulbs are the same what is the total resistance in this circuit? Voltmeter reads 10V

What is the resistance of these bulbs?
More examples… 23/04/2017 3A 6V 12V 4V 2A 1A 2V 3A What is the resistance of these bulbs?

Resistance Resistance is anything that opposes an electric current.
23/04/2017 Resistance is anything that opposes an electric current. Resistance (Ohms, ) = Potential Difference (volts, V) Current (amps, A) What is the resistance of the following: A bulb with a voltage of 3V and a current of 1A. A resistor with a voltage of 12V and a current of 3A A diode with a voltage of 240V and a current of 40A A thermistor with a current of 0.5A and a voltage of 10V

Resistors, bulbs and diodes
23/04/2017

Current-Voltage Graphs
23/04/2017 Voltage on powerpack/V Current/A Voltage/V 12 10 … -10 -12

Current-voltage graphs
23/04/2017 I V I V I V 3. Diode 1. Resistor A diode only lets current go in one direction – it has very high resistance in the other direction Current increases in proportion to voltage 2. Bulb As voltage increases the bulb gets hotter and resistance increases

LDRs and Thermistors 23/04/2017

Two simple components:
23/04/2017 1) Light dependant resistor – resistance DECREASES when light intensity INCREASES 2) Thermistor – resistance DECREASES when temperature INCREASES Resistance Amount of light Resistance Temperature

Wiring a plug 1. Earth wire 4. Live wire 5. Fuse 2. Neutral wire 6.
23/04/2017 1. 2. 3. 4. 5. 6. Earth wire Live wire Fuse Neutral wire Cable grip Insulation The neutral wire of a plug stays at a potential close to zero relative to the Earth The live wire of a plug alternates between positive and negative potential relative to the Earth

DC and AC 23/04/2017 V DC stands for “Direct Current” – the current only flows in one direction: Time 1/50th s AC stands for “Alternating Current” – the current changes direction 50 times every second (frequency = 50Hz) 230V T V

Q. What is the voltage and frequency of this supply?
Using an oscilloscope 23/04/2017 Q. What is the voltage and frequency of this supply? This number tells you how many seconds each square on the horizontal axis represents This number tells you how many volts each square on the vertical axis represents

Words – large, harm, safety, melt, live, circuit, fuse
Fuses 23/04/2017 Fuses are _______ devices. If there is a fault in an appliance which causes the ____ and neutral (or earth) wire to cross then a ______ current will flow through the _____ and cause it to _____. This will break the _______ and protect the appliance and user from further _____. Words – large, harm, safety, melt, live, circuit, fuse

Power and fuses 23/04/2017 Power is “the rate of doing work”. The amount of power being used in an electrical circuit is given by: P I V Power = voltage x current in W in V in A Using this equation we can work out the fuse rating for any appliance. For example, a 3kW (3000W) fire plugged into a 240V supply would need a current of _______ A, so a _______ amp fuse would be used (fuse values are usually 3, 5 or 13A).

Power and fuses Copy and complete the following table: Appliance
23/04/2017 Copy and complete the following table: Appliance Power rating (W) Voltage (V) Current needed (A) Fuse needed (3, 5 or 13A) Toaster 960 240 Fire 2000 Hairdryer 300 Hoover 1000 Computer 100 Stereo 80

In other words, 1 Watt = 1 Joule per second
Energy and Power 23/04/2017 The POWER RATING of an appliance is simply how much energy it uses every second. In other words, 1 Watt = 1 Joule per second E T P E = Energy (in joules) P = Power (in watts) T = Time (in seconds)

Some example questions
23/04/2017 What is the power rating of a light bulb that transfers 120 joules of energy in 2 seconds? What is the power of an electric fire that transfers 10,000J of energy in 5 seconds? Farhun runs up the stairs in 5 seconds. If he transfers 1,000,000J of energy in this time what is his power rating? How much energy does a 150W light bulb transfer in a) one second, b) one minute? Shaun’s brain needs energy supplied to it at a rate of 40W. How much energy does it need during a physics lesson? Damien’s brain, being more intelligent, only needs energy at a rate of about 20W. How much energy would his brain use in a normal day?

Words – fuse, fault, metal, surges, touch
Earth wires 23/04/2017 Earth wires are always used if an appliance has a _____ case. If there is a _____ in the appliance, causing the live wire to ______ the case, the current “_______” down the earth wire and the ______ blows. Words – fuse, fault, metal, surges, touch

Charge (Q) 23/04/2017 As we said, electricity is when electrons move around a circuit and carry energy with them. Each electron has a negative CHARGE. Charge is measured in Coulombs (C). We can work out how much charge flows in a circuit using the equation: Q T I Charge = current x time (in C) (in A) (in s)

Example questions Charge (C) Current (A) Time (s) 5 2 0.4 1 20 0.5 50
23/04/2017 Charge (C) Current (A) Time (s) 5 2 0.4 1 20 0.5 50 250 3 60 A circuit is switched on for 30s with a current of 3A. How much charge flowed? During electrolysis 6A was passed through some copper chloride and a charge of 1200C flowed. How long was the experiment on for? A bed lamp is switched on for 10 minutes. It works on a current of 0.5A. How much charge flowed?

Energy transferred = charge x voltage
Energy and charge 23/04/2017 The amount of energy that flows in a circuit will depend on the amount of charge carried by the electrons and the voltage pushing the charge around: Energy transferred = charge x voltage (in J) (in C) (in V) E Q V

Example questions 23/04/2017 In a radio circuit a voltage of 6V is applied and a charge of 100C flows. How much energy has been transferred? In this circuit the radio drew a current of 0.5A. How long was it on for? A motor operates at 6V and draws a current of 3A. The motor is used for 5 minutes. Calculate: a) The motor’s resistance, b) the charge flowing through it, c) the energy supplied to it A lamp is attached to a 12V circuit and a charge of 1200C flows through it. If the lamp is on for 10 minutes calculate a) the current, b) the resistance, c) the energy supplied to the bulb.

Random questions 23/04/2017 A battery has a voltage of 12V and it puts a current of 3A through a bulb. What is the bulb’s resistance? Another bulb transfers 120C of charge in 2 minutes. What was the current through it? A powerpack transfers 2,000J to a motor. If the motor ran on a voltage of 50V how much charge was transferred? A hairdryer runs on a 50Hz power supply. If it has a power rating of 200W what fuse should it have? An electric fire transfers 3MJ of energy. If it has a power rating of 2KW calculate how long it was on for, the current it ran on (assuming it was connected to the mains supply) and the amount of charge it transferred.

Structure of the atom 23/04/2017 A hundred years ago people thought that the atom looked like a “plum pudding” – a sphere of positive charge with negatively charged electrons spread through it… Ernest Rutherford, British scientist: I did an experiment (with my colleagues Geiger and Marsden) that proved this idea was wrong. I called it the “Scattering Experiment”

The Rutherford Scattering Experiment
23/04/2017 Alpha particles (positive charge, part of helium atom) Thin gold foil Most particles passed through, 1/8000 were deflected by more than 900 Conclusion – atom is made up of a small, positively charged nucleus surrounded by electrons orbiting in a “cloud”.

The structure of the atom
23/04/2017 ELECTRON – negative, mass nearly nothing PROTON – positive, same mass as neutron (“1”) NEUTRON – neutral, same mass as proton (“1”)

The structure of the atom
23/04/2017 Particle Relative Mass Relative Charge Proton 1 +1 Neutron Electron -1 MASS NUMBER = number of protons + number of neutrons He 2 4 SYMBOL PROTON NUMBER = number of protons (obviously)

Isotopes 23/04/2017 An isotope is an atom with a different number of neutrons: Notice that the mass number is different. How many neutrons does each isotope have? O 8 16 O 8 17 O 8 18 Each isotope has 8 protons – if it didn’t then it just wouldn’t be oxygen any more. A “radioisotope” is simply an isotope that is radioactive – e.g. carbon 14, which is used in carbon dating.

Background Radiation 13% are man-made Radon gas Food Cosmic rays
23/04/2017 13% are man-made Radon gas Food Cosmic rays Gamma rays Medical Nuclear power

Types of radiation 23/04/2017 1) Alpha () – an atom decays into a new atom and emits an alpha particle (2 protons and 2 ______ – the nucleus of a ______ atom) Unstable nucleus New nucleus Alpha particle 2) Beta () – an atom decays into a new atom by changing a neutron into a _______ and electron. The fast moving, high energy electron is called a _____ particle. Beta particle New nucleus Unstable nucleus 3) Gamma – after  or  decay surplus ______ is sometimes emitted. This is called gamma radiation and has a very high ______ with short wavelength. The atom is not changed. Words – frequency, proton, energy, neutrons, helium, beta Unstable nucleus New nucleus Gamma radiation

Nuclear fission More neutrons Neutron Uranium or plutonium nucleus
23/04/2017 More neutrons Neutron Uranium or plutonium nucleus Unstable nucleus New nuclei (e.g. barium and krypton)

Chain reactions 23/04/2017 Each fission reaction releases neutrons that are used in further reactions.

Nuclear Fusion in stars
23/04/2017 Proton Neutron

23/04/2017 This slideshow has been made freely available on the TES Resources website. More Science PowerPoints like this can be found at the website This site contains slideshows that cover the AQA, EdExcel, OCR Gateway and OCR 21st Century courses, including the 2011 units, and A Level Physics and KS3 material. Some slideshows are free, others require a small subscription fee to be taken out (currently only £50 for a year). Further details can be found at Education Using PowerPoint.

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