Learning Objective: Recap all of the physics content

TopicSlide numbers Kinetic particle theory3-14 Transfer of energy15-29 Heat and the home30-36 Energy efficiency Generating electricity56-65 Cost of electricity66-75 Waves Origins of the Universe

The next few slides will give you all of the information that you need for a question about kinetic particle theory. Make sure you make a note of anything that you’re not sure of

 You are going to see 3 slides with information about the 3 states of matter.  Translate the information you see into your own words, so that you will be able to remember all of the key facts.

 Particles vibrate in a fixed position  Strong bonds between particles  Particles are close together  Regular pattern in the arrangement  Solids can’t be compressed as the particles have no space to move into and they have a fixed shape as the particles can’t move from place to place

 Particles vibrate and move around each other  Weaker bonds between particles  Particles are close together in a random arrangement  Liquids can’t be compressed as the particles have no space to move into but they can change their shape to match the container that they are in as the particles can move around each other

 Particles move quickly in any direction  No bonds between particles  Particles are far apart  Random pattern in the arrangement  Gases can be compressed or squashed as they have plenty of space to move into. They also flow and completely fill their container as their particles move quickly in all directions.

Examiner’s tip Be able to describe the arrangement and movement of particles in solids, liquids and gases

Quickly jot down any information that you do not know from the next 8 slides.

DO NOT COPY ALL OF THIS 1.Metals are good conductors 2.Non-metals and gases are poor conductors 3.Free electrons are able to move about in metals and the part of the metal atoms that are left behind are charged metal ions 4.These metal ions are packed closely together and vibrate all the time 5.The hotter the metal, the faster the vibrations of the ions 6.This kinetic energy is then transferred from the hotter parts of the metal to the cooler parts of the metal by the free electrons as they collide with the ions as they move about

1.Liquids and gases are fluids 2.When they are heated, they expand as the particles move faster 3.The liquid or gas then becomes less dense as the particles take up more space but they are still the same size 4.The liquid or gas in hot areas is less dense than the liquid or gas in cold areas, so it rises into the cold areas. 5.The denser cold liquid or gas falls into the warm areas. 6.This cycle continues until the heat source is removed 7.The wind is caused by convection currents from the Earth being heated by the sun DO NOT COPY ALL OF THIS

1.All objects emit (give out) and absorb (take in) thermal radiation (infrared radiation) 2.The hotter the object, the more infrared radiation given off 3.Infrared radiation is a type of EM radiation so it travels in waves and can travel in a vacuum 4.Dark, matt materials are good absorbers and emitters of infrared radiation 5.Light, shiny materials are poor absorbers and emitters of infrared radiation DO NOT COPY ALL OF THIS

1.The particles in a liquid have different energies 2.Some will have enough energy to escape from the liquid and become a gas. 3.The remaining particles in the liquid have a lower average kinetic energy than before, so the liquid cools down as evaporation happens. 4.This is why sweating cools you down. 5.The sweat absorbs energy from your skin so that it can continue to evaporate. DO NOT COPY ALL OF THIS

1.The particles in a gas have different energies. Some may not have enough energy to remain as separate particles, particularly if the gas is cooled down. 2.They come close together and bonds form between them. 3.Energy is released when this happens. 4.This is why steam touching your skin can cause scalds: not only is the steam hot, but energy is released into your skin as the steam condenses. DO NOT COPY ALL OF THIS

1.Condensation happens faster if the temperature of the gas is lowered 2.Evaporation happens faster if temperature of the liquid is increased. 3.Evaporation happens faster if the surface area is increased 4.Evaporation happens faster if air is moving over the surface of the liquid DO NOT COPY ALL OF THIS

1.Bigger temperature difference -> the faster the heat transfer 2.Larger surface area -> the faster the heat transfer 3.Larger volume -> the faster the heat transfer 4.Some materials either increase / decrease heat transfer DO NOT COPY ALL OF THIS

1.Small animals have a large surface area to volume ratio so the lose heat quickly 2.Large animals have a low surface area to volume ratio so lose heat slowly 3.Arctic fox has small ears to lose heat slowly 4.Fennec fox has large ears to lose heat quickly 5.Car radiators are flat with many fins so they lose heat quickly 6.Household radiators are thin, flat, sometimes with fins, in order to give heat to the room quickly DO NOT COPY ALL OF THIS

1. Know that air is an excellent insulator and examples of insulation materials using trapped air. 2. Be able to explain why evaporation causes the surroundings to cool. 3. Know the factors affecting the rate at which an object transfers energy by heating and applications of this. 4. Know how the nature of a surface affects the amount of infrared emitted. 5. Understand the difference between an object emitting infrared radiation and absorbing infrared radiation.

In order to save money, people can change the materials used in housing. E.g. The materials used for their windows Energy-saving solutions cost money to buy and install. The payback time of an energy-saving solution is a measure of how cost-effective it is. Here is the equation to calculate payback time: Payback time (years) = cost of installation (£) ÷ savings per year in fuel costs (£) If the payback time is too long, the energy-saving solution is not cost-effective HEAT AND THE HOME

1.Specific heat capacity of materials can be found by using the formula: E = m × c × ө 2.This tells us how much energy is needed to increase the temperature of 1kg by one degree Celsius 3.The higher the specific heat capacity, the more energy the material can store (e.g. water) 4.Materials have a U-value which tells us how well heat travels through a material 5.The lower the U-value, the better it is at insulating

1. Know that air is an excellent insulator and examples of insulation materials using trapped air. 2. Be able to explain why evaporation causes the surroundings to cool. 3. Know the factors affecting the rate at which an object transfers energy by heating and applications of this. 4. Know how the nature of a surface affects the amount of infrared emitted. 5. Understand the difference between an object emitting infrared radiation and absorbing infrared radiation.

 Magnetic  Kinetic (movement energy)  Heat (thermal energy)  Light  Gravitational potential  Chemical  Sound  Electrical  Elastic potential  Nuclear Most Kids Hate Learning GCSE Energy Names

Useful Wasted Input

Useful Wasted Input

Useful Wasted Input

Useful Wasted Input

Useful Wasted Input

The thickness of each arrow is drawn to scale to show the amount of energy

Notice that the total amount of energy before is equal to the total amount of energy after (conservation of energy)

Although the total energy out is the same, not all of it is useful.

Efficiency is defined as Efficiency (%) = useful energy output x 100 total energy input  The closer the efficiency is to 1 or 100%, the more efficient the device is and the less energy it wastes  No device will have an efficiency of 1 or 100% as some energy is always lost as heat to the surroundings

Efficiency = 75 x 100 = 15% 500

We need to use energy efficient devices as they use less energy to do the same job when compared to less energy efficient devices. Why do you think this is a good thing? Why use energy efficient devices? 1. Save money 2. Less energy resources are used so there will be more for the future 3. Less CO 2 is produced so the effect of global warming will be decreased

Examiner’s tip Know how to use the equation and calculate the efficiency either as a decimal or as a percentage. Understand why a device or process can never be greater than 100% efficient. Understand the term ‘pay-back’ time in relation to heating and insulating buildings.

1.Fossil fuel is burnt 2.The heat turns water to steam 3.The steam turns a turbine 4.The turbine turns a generator 5.This induces a current and creates electricity

Electricity from a power station goes to: 1.Step-up transformers – increases the voltage which decreases the current and reduces energy loss 2.High voltage transmission lines 3.Step-down transformers – decrease the voltage to make it safe for us to use 4.Consumers, for example homes, factories and shops.

Energy sourceAdvantagesDisadvantages CoalRelatively cheap to mine, ready made fuels Non-renewable, burning produces CO 2 OilShort start-up time, ready made fuels Non-renewable, burning produces CO 2 Gas Slightly cleaner fuel than oil and gas and is a ready made fuel Non-renewable, burning produces CO 2 Nuclear powerProduces lots of energy, does not produce CO 2 Non-renewable, produces dangerous nuclear waste All of these methods are used to heat water to create steam which is used to turn the turbine and generate electricity

Energy sourceAdvantagesDisadvantages WindRenewable, no fuel costs No wind sometimes, noisy HydroelectricRenewable, no fuel costs Can flood areas, disrupts habitats SolarRenewable, no fuel costs No sun at night, some countries don’t get enough sun in the day, panels are expensive GeothermalRenewable, no fuel costs Only available in volcanic regions, 1.Wind, hydroelectricity and geothermal all turn a turbine which will create electricity 2.Solar cells use light to create electricity

Power stations fuelled by fossil fuels or nuclear fuels are reliable sources of energy. This means they can provide power whenever it is needed. 1.gas-fired station (shortest start-up time) 2.oil-fired station 3.coal-fired station 4.nuclear power station (longest start-up time) Nuclear power stations and coal-fired power stations provide 'base load' electricity - run all the time as they take the longest time to start up. Oil-fired and gas-fired power stations are often used to provide extra electricity at peak times, because they take the least time to start up. The fuel for nuclear power stations is relatively cheap, but the power stations themselves are expensive to build. It is also very expensive to dismantle old nuclear power stations and to store their radioactive waste, which is a dangerous health hazard.

1. Be able to draw and label a block diagram of a power station showing the main parts. 2. Be able to distinguish the difference between waves and tides. 3. Be able to describe the advantages and disadvantages of solar cells. 4. Understand that to prevent carbon dioxide building up in the atmosphere we can catch it and store it. Some of the best natural containers are old oil and gas fields. 5. Be able to identify and label a diagram of the main parts of the National Grid. Wave energy - the rise and fall of the water (kinetic energy) drives generators and makes electricity Tidal energy – when the tide goes in and out, there is a large amount of kinetic energy. This goes through a tidal barrage that contains generators which makes electricity Carbon capture and storage stops carbon dioxide building up in the atmosphere. It involves separating carbon dioxide from waste gases. The carbon dioxide is then stored underground, for example in old oil fields or gas fields.

We can calculate the amount of electrical energy transferred by an appliance and how much it costs to run. This is useful for comparing the advantages and disadvantages of using different electrical appliances

 E = P × t  E - energy transferred in kWh / J  P - power in kW  T - time in h.  Power is sometimes measured in kWh. To convert from W to kW you must divide by 1,000.  E.g. 2,000 W = 2,000 ÷ 1,000 = 2 kW.

 Electricity meters measure the number of units of electricity used. The more units used, the greater the cost. total cost = number of units × cost per unit  E.g. if 5 units of electricity are used at a cost of 8p per unit, the total cost will be 5 × 8 = 40p  The number of units used can be calculated using this equation: total cost = power (kW) × time (h) × cost per unit

 Know the units of each term in the equation.  Know how to convert power from watts to kilowatts and vice versa.  Know how to convert time from hours to minutes and seconds and vice versa, and be careful to make these conversions in an exam if necessary.

 Waves are vibrations that transfer energy from place to place without matter (solid, liquid or gas) being transferred.  Some waves must travel through a substance. The substance is known as the medium and it can be solid, liquid or gas.

 In transverse waves, the oscillations (vibrations) are at right angles to the direction of travel and energy transfer  Light and other types of electromagnetic radiation are transverse waves. All types of electromagnetic waves travel at the same speed through a vacuum, such as through space.

 In longitudinal waves, the oscillations are along the same direction as the direction of travel and energy transfer.  Sound waves and waves in a stretched spring are longitudinal waves.

 The wavelength of a wave is the distance between a point on one wave and the same point on the next wave.  The frequency of a wave is the number of waves produced by a source each second. It is also the number of waves that pass a certain point each second.

 The speed of a wave is related to its frequency and wavelength, according to this equation: v = f × λ  v is the wave speed in metres per second, m/s  f is the frequency in hertz, Hz  λ (lambda) is the wavelength in metres, m.

The angle of incidence equals the angle of reflection  Sound waves and light waves reflect from surfaces.  Smooth surfaces produce strong echoes when sound waves hit them, and they can act as mirrors when light waves hit them. The waves are reflected uniformly and light can form images

 Rough surfaces scatter sound and light in all directions. However, each tiny bit of the surface still follows the rule that the angle of incidence equals the angle of reflection

 Sound waves and light waves change speed when they pass across substances with different densities.  This causes them to change direction and this effect is called refraction.  Refraction doesn't happen if the waves cross the boundary at an angle of 90°(the normal) - they carry straight on.

 When waves meet a gap in a barrier, they carry on through the gap and spread out  How much they spread out depends on how the width of the gap compares to the wavelength of the waves.  Lots of diffraction happens when the wavelength is the same size as the gap.

 A gap similar to the wavelength causes a lot of spreading with no sharp shadow, e.g. sound through a doorway  A gap much larger than the wavelength causes little spreading and a sharp shadow, e.g. light through a doorway.

 Sound waves and light waves change speed when they pass across substances with different densities.  This causes them to change direction and this effect is called refraction.  Refraction doesn't happen if the waves cross the boundary at an angle of 90°(the normal) - they carry straight on.

 Longitudinal waves  Echoes are reflections of sound waves  Sound can only travel in a solid, liquid or gas  A loud sound has a high amplitude  A quiet sound has a small amplitude  A high pitched sound has a high frequency  A low pitched sound has a low frequency  The normal range of human hearing is between about 20 Hz and 20 kHz  The range becomes less as we get older.  Sounds with frequencies above about 20 kHz are called ultrasound.

Contains 7 different types of radiation Shortest wavelength Highest frequency Longest wavelength Shortest frequency

 Used for TV and radio  TVs use higher frequencies than radios  Diffraction allows radio signals to be received behind hills and repeater stations are used to improve reception

 Used to transmit signals such as mobile phone calls.  Microwave transmitters and receivers on buildings and masts communicate with the mobile telephones in their range.  Some mobile phones may be a health risk.  Others think that the intensity of the microwaves is too low to damage tissues by heating, and microwaves are not ionising.  Some wavelengths can be used to transmit information to and from satellites in orbit. Satellite TV signals use microwaves.

VISIBLE LIGHT  Visible light helps us to communicate via sight  Cameras and video recorders use visible light  Very bright light damages our eyes INFRARED  Infrared is used in toasters, heaters and grills and can cause burns  Used in burglar alarms, remote controls and security alarms

Examiner’s tip  Be able to construct a ray diagram to show the image formed by a plane mirror.  Know the order of the electromagnetic waves within the spectrum in terms of energy, frequency and wavelength.  Be able to complete diagrams for wave fronts showing reflection, refraction and diffraction.  Learn the units of the terms in the equation and know how to convert kilohertz to hertz.  Know how radio waves, microwaves, infrared and visible light can be used in communications.  Know the relationship between pitch and frequency.

The next few slides will give you all of the information that you need for a question about the origins of the Universe. Make sure you make a note of anything that you’re not sure of

Examiner’s tip Be able to explain the term ‘red-shift’ and the ‘Big Bang’ theory.

 Theory – an idea but not a fact  The theory states that originally all the matter in the universe was concentrated into a single incredibly tiny point.  This began to enlarge rapidly in a hot explosion (called the Big Bang), and it is still expanding today.  The Big Bang happened about 13.7 billion years ago

 Cosmic microwave background radiation (CMBR) – thought to be left over heat from the original explosion  Doppler effect  Red-shift

 When a police car goes past, its siren is high-pitched as it comes towards you, then becomes low-pitched as it goes away.  When a source (e.g. galaxy) moves towards an observer, the observed wavelength decreases and the frequency increases.  When a source (e.g. galaxy) moves away from an observer, the observed wavelength increases and the frequency decreases.

 When an object (e.g. galaxy) moves away from an observer, its light is affected by the Doppler effect  We know our sun has helium in it because there are black lines in the spectrum of the light from the Sun where helium has absorbed light. These lines form the absorption spectrum for helium.  When we look at the spectrum of a distant star, we still see an absorption spectrum. However, the pattern of lines has moved towards the red end of the spectrum, as you can see above.

 The positions of the lines have changed because of the Doppler effect. Their wavelengths have increased and their frequencies have decreased.  The further from us a star is, the more its light is red-shifted. This tells us that distant galaxies are moving away from us, and that the further away a galaxy is, the faster it's moving away.  Red shift tells us how far away a galaxy is and the speed at which it is getting further away from us