EDEXCEL INTERNATIONAL GCSE IN PHYSICS - Revision List for January Mock Examination

January Exam – 2 hours – Testing all of the material below NOT IN BOLD TYPE. (Triple and combined science) except section 6.

Section 1: Forces and motiona) Units

use the following units: kilogram (kg), metre (m), metre/second (m/s), metre/second2 (m/s2), newton (N), second (s), newton per kilogram (N/kg), kilogram metre/second (kg m/s).

b) Movement and position

plot and interpret distance-time graphsknow and use the relationship: average speed = distance moved / time takendescribe experiments to investigate the motion of everyday objects such as toy cars or tennis ballsknow and use the relationship: acceleration = change in velocity / time taken a = (v – u) / tplot and interpret velocity-time graphsdetermine acceleration from the gradient of a velocity-time graphdetermine the distance travelled from the area between a velocity-time graph and the time axis.

c) Forces, movement, shape and momentum

describe the effects of forces between bodies such as changes in speed, shape or direction

SpeedWhen an object is stationary it has an equal force pushing down and up. The downward force, being gravity, and the upward force being the surface the object is on. The object is not floating but it is not sinking into the ground either.

When an object is accelerating it has the same upwards and downwards forces but it also has forwards and backwards forces (drag and friction). The forward force is larger than the backward force when an object is accelerating.

When an object is going at a constant speed it has downward and upward forces as well as forward and backward forces. The forward and backward forces are equal, so the speed doesn't change even though the object is moving.

When an object is decelerating it has the equal upward and downward forces as well as forward and backward forces, but the backward force is larger than the forward one, slowing the object down.

ShapeAffects momentum. Force = change in momentum / time taken. An example of this is crumple zones in car decrease the force on the passengers.

DirectionWhich ever direction the force is greatest in will be the direction the object travels in.

identify different types of force such as gravitational or electrostaticGravity: Acts downwardsUp thrust: Acts upwardsDrag: Acts against the movementVarious types of force:• push/pull (contact force)• tension-the pull at both ends of a stretch spring, string or rope

• compression• thrust/upthrust• load• effort• *weight/gravitational• *electrical/electrostatic• *magnetic*the last three forces are non-contact, they can act without touching an object

distinguish between vector and scalar quantitiesScalars have magnitude (size) while vectors have both magnitude and a direction.  [For example velocity is a speed in a given direction (Vector)]

understand that force is a vector quantityForce is a vector quantity because it has magnitude, it is measured in newtons but it acts in a direction

find the resultant force of forces that act along a line

understand that friction is a force that opposes motionknow and use the relationship between unbalanced force, mass and acceleration:force = mass × acceleration F = m × aknow and use the relationship: weight = mass × g; W = m × g

describe the forces acting on falling objects and explain why falling objects reach a terminal velocityWhen first an object is falling it is accelerating towards the ground - the force acting downwards (gravity) is larger than the force acting upwards (air resistance). But when air resistance and gravity become equal the object  (the air resistance increases until it equals the object's weight) will have reached its maximum speed; its terminal velocity. Acceleration will no longer happen at this point. Earth's gravity- Weight: has direction (vector quantity), pulls object downward towards the centre of the EarthAir resistance/Drag: upwards force, pushes object upwards

describe experiments to investigate the forces acting on falling objects, such as sycamore seeds or parachutesDropping parachutes from a given height; this shows us that gravity is acting on them. By increasing the size of the parachute and recording the results we can see that air resistance also has an effect on falling objects; plotting a graph should reveal that bigger surface area takes more time, from which we can infer that air resistance acts on the falling objects.

Example: • Get five different sizes of sycamore seeds• Roughly measure, and label them with, their surface area by multiplying the length by width• Hold one at the top of a meter ruler• Drop it and time how long it takes to reach the ground• Repeat this three times for each of the five seeds• Then plot a scatter graph with surface area on the y axis (mm/cm) and time on the x axis (s)• You should find that the line of best fit is a diagonal line pointing away from 0, this represents a positive correlation meaning the larger

the surface area the longer it took to fall

This is because the larger seeds had more surface area to experience air resistance, this is a type of friction that opposes gravity, therefore slowing down the time taken for gravity to bring them to the ground.

describe the factors affecting vehicle stopping distance including speed, mass, road condition and reaction timeVehicle stopping distance = ( reaction time (a.k.a thinking time) x constant speed ) + breaking distance vehicle stopping distance = thinking distance + braking distancedistance = speed x time, so it becomes thinking distanceThinking distance: How far the car travels at constant speed before the driver reacts by applying the car brakesBraking distance: Distance travelled by the car as it decelerates to a stop

Factors that affect the stopping distance are:• The condition of the driver; drugs/ tiredness (thinking distance)• How worn the brakes/ tyres are• If the weather conditions are poor• How heavy the car is• The speed the car is travelling atAs speed increases, stopping distance increases, and as mass increases, force needed to stop car increases (F=ma). As reaction time increases, stopping distance increases. Dry weather=more friction, Rainy=less friction, as water acts as lubricant. 

know and use the relationship: momentum = mass × velocity p = m × vuse the ideas of momentum to explain safety features in a carCars have safety features which increase the time over which the car’s momentum changes in an accident. Crumple zones and air bags increase the time during which the car is decelerating so forces acting on passengers are reduced. Seat belts so reduced deceleration applies to passengers as well.

use the conservation of momentum to calculate the mass, velocity or momentum of objectsuse the relationship: force = change in momentum / time taken

demonstrate an understanding of Newton’s third law

know and use the relationship: moment = force × perpendicular distance from the pivotknow that the weight of a body acts through its centre of gravityknow and use the principle of moments for a simple system of parallel forces acting in one planeunderstand that the upward forces on a light beam, supported at its ends, vary with the position of a heavy object placed on the beam

describe experiments to investigate how extension varies with applied force for helical springs, metal wires and rubber bands• Attach a spring to a newton meter and measure its length• Add a 50g weight and measure again• continue to add another weight and take another measurement• Do this up to 400gby plotting a graph from the results from this you can see the extension increases with force; as each time a weight is added the spring gets longer.

understand that the initial linear region of a force-extension graph (straight line through the origin) is associated with Hooke’s law: the extension of the spring is proportional to the force until the elastic limit. After the spring has been stretched beyond this limit, it has changed shape permanently and will not return to it’s original length.

describe elastic behaviour as the ability of a material to recover its original shape after the forces causing deformation have been removed.

d) Astronomy

understand gravitational field strength, g, and know that it is different on other planets and the moon from that on the Earth.explain that gravitational force:- causes moons to orbit planets- causes the planets to orbit the sun- causes the moon and artificial satellites to orbit the Earth- causes comets to orbit the sun

describe the differences in the orbits of comets, moons and planetsComets orbit the sun and their orbits are very elliptical. The gravitational forces increase and comets speed up when they get closer to the sun. When they get further from the sun, the gravitational forces decrease so they slow down.Moons orbit a planet and it takes our moon 29.5 days to orbit the earthPlanets orbit the sun and are held in orbit by its gravitational pull.

use the relationship: orbital speed = (2× π × orbital radius) / time periodv = (2× π × r) / Tunderstand that:- the universe is a large collection of billions of galaxies- a galaxy is a large collection of billions of stars- our solar system is in the Milky Way galaxy.

Section 2: Electricity

a) Units

use the following units: ampere (A), coulomb (C), joule (J), ohm (Ω), second (s), volt (V), watt (W).

b) Mains electricity

understand and identify the hazards of electricity including frayed cables, long cables, damaged plugs, water around sockets, and pushing metal objects into socketsDamaged plugs and frayed cables: expose the parts of the plug that are carrying the electricityPushing metal objects into sockets: get an electric shockLong cables: can cause spillsWater around sockets: Water can conduct electricity at high voltages

understand the uses of insulation, double insulation, earthing, fuses and circuit breakers in a range of domestic appliancesInsulation: casing of a plug is made from plasticDouble insulation: if an insulator cases all electrical parts of an appliance so the user cannot touch themEarthing: the metal casing of an appliance is connected to the earth wire so there is a low resistance path for the current if the live wire comes in contact with the casingFuses: cylinders or cartridges that contain a thin piece of wire made from metal that has a low melting point, which becomes very hot and melts, shutting the circuit offCircuit breakers: modern safety devices which open a switch if too large a current flows in a circuit, making it incomplete and can be reset by pressing a reset button

understand that a current in a resistor results in the electrical transfer of energy and an increase in temperature, and how this can be used in a variety of domestic contextsHeating elements in kettles, toasters and light bulbs are designed to have a high resistance

know and use the relationship: power = current × voltage P = I × Vand apply the relationship to the selection of appropriate fusesuse the relationship: energy transferred = current × voltage × time E = I × V × tunderstand the difference between mains electricity being alternating current (a.c.) and direct current (d.c.) being supplied by a cell or battery.a.c- flow of electricity is constantly changing directiond.c- current is always in the same direction

c) Energy and potential difference in circuits

explain why a series or parallel circuit is more appropriate for particular applications, including domestic lightingSeries circuit- One switch can turn all the components on and

off together-If one component breaks, it causes a gap in the circuit and all the other components will go off-The voltage supplied by the power supply is “shared” between all the components, so the more bulbs you add to a series circuit the dimmer they all become. Larger resistance of the component=bigger share of the voltage.-The current is the same in all parts of the circuit

Parallel circuit- Switches can be placed in each part of the circuit to switch each component on and off individually, or all together

- If one component breaks, only the components

on the same branch of the circuit will be affected - Each branch of the circuit receives the same voltage so if more bulbs are added to a circuit in parallel they all stay bright understand that the current in a series circuit depends on the applied voltage and the number and nature of other components

describe how current varies with voltage in wires, resistors, metal filament lamps and diodes, and how this can be investigated experimentallyWires: Current and voltage increase proportionallyResistors: The current flowing through a resistor at a constant temperature is directly proportional to the voltage across itFilament lamps: The current flowing through the lamp is not proportional to the voltage across it but the resistance increase as the temperature of the filament increases.Diodes: Have a very high resistance in one direction so current can only flow in the other direction

describe the qualitative effect of changing resistance on the current in a circuitIncreasing the resistance will decrease the current. This can be achieved by adding more components or ones with higher resistance.Decreasing the resistance will increase the current. This can happen if components are removed or replaced by those with lower resistance.

describe the qualitative variation of resistance of LDRs with illumination and of thermistors with temperatureAn LDR is a light dependent resistor. Its resistance changes with the intensity of light: the brighter it is the less resistance; the less light the more resistance.Thermistors are temperature dependent resistors. In hot conditions there will be less resistance where as in the cold the resistance is high.

know that lamps and LEDs can be used to indicate the presence of a current in a circuitknow and use the relationship: voltage = current × resistance V = I × Runderstand that current is the rate of flow of chargeknow and use the relationship: charge = current × time Q = I × tknow that electric current in solid metallic conductors is a flow of negatively charged electrons

know that:• voltage is the energy transferred per unit charge passed• the volt is a joule per coulomb.d) Electric chargeidentify common materials which are electrical conductors or insulators, including metals and plastics

describe experiments to investigate how insulating materials can be charged by frictionIf an uncharged plastic rod is rubbed with an uncharged cloth, it is possible for both to become charged. The electrons from the atoms of the rod may move onto the cloth, creating an imbalance of charge in both objects.The rod is short of electrons and is positively chargedThe cloth has excess electrons and is negatively charged

explain that positive and negative electrostatic charges areproduced on materials by the loss and gain of electrons

understand that there are forces of attraction between unlike charges and forces of repulsion between like charges

explain electrostatic phenomena in terms of the movement of

electronsElectrostatic phenomena is an event where static electricity has a specific effect: for example a static shock. Electrons move from one material to another, the material with a negative charge will then look for some way to earth its charge: like clouds through lightening or a car through your hand and body.

explain the potential dangers of electrostatic charges, eg when fuelling aircraft and tankers

When a large electrostatic charge builds up it can create a spark. When refuelling vehicles the fuel rubbing along the pipe can cause an electrostatic charge, if this sparks if could ignite the fuel causing a fire or explosion. (This can be avoided if the charge is brought to earth by a wire attached to the plain or tanker)

TV and computer screens become charged with static electricity as they are used. The charges attract light particles such as dust.

Our clothes can be charged with static electricity and as we remove them, there is a possibility of receiving a small electric shock.

explain some uses of electrostatic charges, eg in photocopiers and inkjet printers.

In photocopiers and inkjet printers where the ink is given a charge, and the parts of the paper where its wanted is given the opposite charge, so that the ink is automatically attracted to the right parts of the paper.

In paint spraying where an electrical supply’s positive terminal is connected the metal spray nozzle and it’s negative terminal is connected to the object. The paint droplets are attracted to the surface of the object and places that may not receive a good coating are painted.

In photocopiers where part of the drum is charged, the image of the object to be copied is formed on another part with the charge staying only where the image is dark and the toner is on another part of the drum and sticks to charged areas. The toner is removed by another part of the drum.The paper is pressed against the toner image to put the image on paper. It is then heated to melt the toner image and form a permanent image on paper.

Electrostatic precipitators are used in heavy industrial plants to remove pollutants such as ash and dust from the smoke.As the smoke rises up the chimney, it passes through a mesh of negatively charged wires and the pollutants become negatively charged. These particles are attracted by and stick to large metal earthed plates and the cleaner smoke is released into the atmosphere.The earthed plates are given a sharp rap when they are covered in dust and ash, which fall into collection boxes.

Section 3: Waves

a) Units

use the following units: degree (°), hertz (Hz), metre (m), metre/second (m/s), second (s).

b) Properties of waves

understand the difference between longitudinal and transverse waves and describe experiments to show longitudinal and transverse waves in, for example, ropes, springs and waterLongitudinal waves vibrate along the direction in which the wave is travelling whilst transverse waves vibrate at right angles to the direction in which the wave is moving.If you push and pull the end of a slinky spring in a direction parallel to its axis, you can see energy travelling along itIf you waggle one end of a slinky spring from side to side you will see waves travelling through it

define amplitude, frequency, wavelength and period of a waveAmplitude- The maximum movement of particles from their resting position caused by a waveFrequency- The number of waves produced each second by a sourceWavelength- The distance between a particular point on a wave and the same point on the next wavePeriod- The time it takes for a source to produce one wave

understand that waves transfer energy and information without transferring matterknow and use the relationship: wave speed = frequency × wavelength v = f × λuse the relationship: frequency = 1 / time period f = 1 / Tuse the above relationships in different contexts including sound waves and electromagnetic wavesunderstand that waves can be diffracted when they pass an edgeunderstand that waves can be diffracted through gaps,and that the extent of diffraction depends on the wavelength and the physical dimension of the gap.

c) The electromagnetic spectrum

understand that light is part of a continuous electromagnetic spectrum which includes radio, microwave, infrared, visible, ultraviolet, x-ray and gamma ray radiations and that all these waves travel at the same speed in free space

identify the order of the electromagnetic spectrum in terms of decreasing wavelength and increasing frequency, including the colours of the visible spectrumRadio waves: Longest wavelengthLowest frequencyCarry the least energy

-Used mainly in communication-They are emitted by a transmitter and as they cross an aerial, they are detected and the information they carry can bereceived-TV and FM radio use radio waves with the shorter wavelengths to carry their signals

Microwaves: 2nd longest wavelength2nd lowest frequencyCarry the 2nd least energy-Used for cooking foods, communication and radar-Food placed in a microwave oven cooks more quickly than in a normal oven because water molecules in the food absorb the microwaves and become very hot. The food cooks throughout rather than just from the outside.-The waves pass easily through the Earth’s atmosphere and so are used to carry signals to orbiting satellites. From here the signals are passed on to their destination or to other orbiting satellites. Microwaves also carry messages sent to and from mobile phones.-Microwaves have special screens that reflect microwaves and keep them inside the oven as they can heat body tissue. Microwaves from mobile phones carry much less energy.

Infrared waves: 3rd longest wavelength3rd lowest frequencyCarry the 3rd least energy-All objects including your body emit IR radiation. The hotter an object is, the more energy it will emit as IR.-Used in toasters, grills and electric fires-Special cameras designed to detect IR waves can be used to create images in the absence of visible light=these cameras have many uses such as searching for people trapped in collapsed buildings, tracking criminals and checking for heat loss from buildings

Visible light: Median wavelengthMedian frequencyCarry the median amount of energy-Part of the electromagnetic spectrum visible to the human eye-Used to see, in lasers to read CDs and barcodes, sent along optical fibres for communication and viewing inaccessible parts of the body of a patient-Can be detected digital camera sensors and used to take photos and videos

Ultraviolet light: 3rd shortest wavelength3rd highest frequencyCarry the 3rd highest energy-Part of the light emitted by the sun-Harmful to human eyes and can cause damage to the skin-Causes the skin to tan, but overexposure will lead to sunburn and blistering. Can also cause skin cancer and blindness.-Protective eyewear and skin cream can block UV rays and will reduce the harmful effects of the radiation-UV light causes some chemicals to glow or fluoresce when exposed to it so it is used in security markers. Ink invisible in normal light but visible in UV light-Fluorescent tubes glow as the mercury vapour inside gives off UV rays when a current is passed through it. White light is given out when the UV light strikes the fluorescent powder coating the tube

X-rays: 2nd shortest wavelength2nd highest frequencyCarry the 2nd highest energy-Can easily pass through soft body tissue but cannot pass through bones so X-ray pictures can be taken to check a patient’s bones-Overexposure can cause cancer so people who work with it regularly stand behind lead screens or wear protective clothing-Used in industry to check the internal structures of objects- eg. Looking for cracks and faults in buildings or machinery-Used at airports as part of security checking

Gamma rays: shortest wavelengthhighest frequencyCarry the highest energy-Highly penetrating and can cause damage to living cells=can cause mutations in genes and can lead to cancer-Used to sterilise medical instruments, to kill microorganisms to ensure food keeps for longer and to treat cancer using radiotherapy-Can cause and cure cancer=a small dose may be enough to cause changes to a cell such as mutations and make it become cancerous=a large dose directly targeted at the cancerous growth can be used to completely kill the cancer cells

explain some of the uses of electromagnetic radiations, including:• radio waves: broadcasting and communications• microwaves: cooking and satellite transmissions• infrared: heaters and night vision equipment• visible light: optical fibres and photography• ultraviolet: fluorescent lamps• x-rays: observing the internal structure of objects and materials and medical applications• gamma rays: sterilising food and medical equipmentunderstand the detrimental effects of excessive exposure of the human body to electromagnetic waves, including:• microwaves: internal heating of body tissue• infra-red: skin burns• ultraviolet: damage to surface cells and blindness• gamma rays: cancer, mutation.and describe simple protective measures against the risks.

d) Light and sound

understand that light waves are transverse waves which can be reflected, refracted and diffracteduse the law of reflection (the angle of incidence equals the angle of reflection)

construct ray diagrams to illustrate the formation of a virtual image in a plane mirror

describe experiments to investigate the refraction of light, using rectangular blocks, semicircular blocks and triangular prismsPlace a block of glass on a piece of paper, drawing an outline.At one point, draw the normal line.Draw a line at 30 degrees to the normal line, shine a ray of light down this line.Draw a line where the light comes out the other side. Connect the two lines, drawing the refracted ray.Measure the angle of the emergent ray.Repeat for different shaped glass.

know and use the relationship: n = sin i / sin r

describe an experiment to determine the refractive index of glass, using a glass blockShine a ray of light through a glass block, measure the angle of incidence and the angle of refraction.Do sin(i) divided by sin(r) and you will have the refractive index of glass.

describe the role of total internal reflection in transmitting information along optical fibres and in prismsBeyond the critical angle, light will be reflected back into the medium they came from at the same angle. In this way they are trapped in the medium.By reflecting light past its critical angle you can make it travel through a medium to send information: this is done in optical fibres.

explain the meaning of critical angle cWhen light travels from one medium to another it is refracted; it changes angle due to change in density.Past a certain angle the light will simply be refracted back into the medium it is in, this angle is the critical angle.

know and use the relationship: n = 1 / sin c

understand the difference between analogue and digital signalsAnalogueThe amplitude and/or frequency constantly vary.

DigitalConsists of pulses with two states: on; off

describe the advantages of using digital signals rather than analogue signalsThe term noise means the random signals picked up by waves. Radios may crackle or internet may looses connection. This effects analogue signals badly as each time it is amplified the noise also gets amplified, this alters the signal making it hard or impossible to identify as the original signal.

In digital signals any noise picked up is likely to be of a smaller amplitude than that if the on state, this means something receiving it will ignore the noise as it is neither on nor off, this makes them less likely to be distorted.

describe how digital signals can carry more informationDigital signals have a larger bandwidth

understand that sound waves are longitudinal waves which can be reflected, refracted and diffractedknow that the frequency range for human hearing is 20 Hz – 20 000 Hz

describe how to measure the speed of sound in airMeasure the distance between two places, have a sound made in one place, as soon as you see the sound has been made start a stop watch, as soon as you hear the sound made stop the stopwatch.

understand how an oscilloscope and microphone can be used to display a sound wave

describe an experiment using an oscilloscope to determine the frequency of a sound waveHave an noise made into a microphone attached to an oscilloscope, for example have someone try to sing a note. See how many oscillations there are per second, this will be your frequency. Try changing the pitch of the note and see it the number of oscillations per second changes.

relate the pitch of a sound to the frequency of vibration of the sourcerelate the loudness of a sound to the amplitude of vibration.

Section 4: Energy resources and energy transfer

a) Units

use the following units: kilogram (kg), joule (J), metre (m), metre/second (m/s), metre/second2 (m/s2), newton (N), second (s), watt (W).

b) Energy transfer

describe energy transfers involving the following forms of energy: thermal (heat), light, electrical, sound, kinetic, chemical, nuclear and potential (elastic and gravitational)Energy can change from one form to another, and frequently does. Some examples include:Chemical energy in food turns into kinetic energy for movement;Electrical energy in a circuit turns into heat energy in a resistor;Kinetic energy in your muscles turns into sound energy from you voice.Elastic potential energy in a taught rubber band turns into kinetic energy when it sails through the air.

understand that energy is conservedknow and use the relationship: efficiency = useful energy output / total energy input

describe a variety of everyday and scientific devices and situations, explaining the fate of the input energy in terms of the above relationship, including their representation by Sankey diagramsWith all devices that aim to use energy for a reason, some of the energy put in to run it comes out as a non useful form of energy. The more energy that comes out as useful, the more efficient the object is. For instance, a light bulb wants to create light energy, but it creates heat at the same time. This is the same for many processes: a fire (for warmth) creates light; a pepper grinder creates sound (even though you just want it to move).Sankey diagrams use an arrow to represent the energy going in and out of a process:

Here 100j of energy is going in. All 100j must come out. 90j come out as heat, 10j come out as light.

describe how energy transfer may take place by conduction, convection and radiationConduction is when energy is passed from one particle to another via contact. For example heat is passed from your skin to a window when they touch.

Convection is when particles with energy rise, the space they leave is filled by other particles. If the source of energy continues these new particles will also gain energy, they will then rise and the process will be repeated.

Radiation is when heat is transferred as infra red waves. These waves can travel through space and be conducted or reflected.

explain the role of convection in everyday phenomenaConvection is helpful as it distributes heat energy. This is useful in many situations, for example, a radiator in one place will be able to heat a whole room, as hot air will rise away from it creating a current of cool air to be heated.

explain how insulation is used to reduce energy transfers from buildings and the human body.An insulator is something that is bad at conducting. If something with heat energy is surrounded by an insulator, it wont lose heat by conduction. This is true in buildings where insulating materials are put in walls and on floors to stop heat being lost from inside. This is the same in humans where we wear clothes to stop heat being lost from conduction. Air is a poor conductor, so materials with many air gaps in are also poor conductors; air trapped between double glazing prevents heat loss through windows.

c) Work and power

know and use the relationship between work, force and distance moved in the direction of the force:work done = force × distance moved W = F × dunderstand that work done is equal to energy transferredknow and use the relationship: gravitational potential energy = mass × g × heightGPE = m × g × hknow and use the relationship: kinetic energy = ½ × mass × speed2 KE = ½ × m × v2

understand how conservation of energy produces a link between gravitational potential energy, kinetic energy and work

describe power as the rate of transfer of energy or the rate of doing workuse the relationship between power, work done (energy transferred) and time taken:power = work done / time taken P = W / t

d) Energy resources and electricity generation

understand the energy transfers involved in generating electricity using:• wind• water• geothermal resources• solar heating systems• solar cells• fossil fuels• nuclear power

describe the advantages and disadvantages of methods of large-scale electricity production from various renewable and non-renewable resources.

Energy Source

Advantages of Use Disadvantages of Use

Fossil FuelsFuels readily available, easy to

make electricity.

Fuels are non-renewable, produce C02

and so add to global warming, acid rain. Oil spills damage environment.

NuclearCreates large amounts of energy, is reliable and relatively cheap to

set up. Produces no C02.

Expensive to decommission power stations after use. Waste is produced that is dangerous for long periods. Reactors

that are not cooled will overheat and release waste.

WindProduces no C02. Once setup

takes little maintenance. Renewable.

Expensive to set up. Installations may be noisy and seen as ugly. Unreliable as you

cannot count on the wind all the time.

Wave

Produces no C02.  Small devices can produce large amounts of

electricity. Out to sea means out of sight. There are large areas

unused across the globe. Renewable.

Easily destroyed by bad weather. Electricity produced needs to be transferred over long distances.

Expensive to set up.

Tidal

Reliable as the tides are predictable as they depend on the

Sun and Moon.Produces no C02. Renewable.

Few areas are suitable of being dammed. The dam restricts movement of sea life. Silt will build up. tides vary in strength throughout the day. Expensive to set up.

Hydroelectric

Produce no C02. Once set up have little maintenance cost.

Create useful water resources. Can be turned on and off

instantly. Renewable.

Expensive to build. Destroy ecosystems. If dams break damaging flooding will occur. Most areas in the world that can

be used are being used.

Geothermal

Virtually emission free. Some reduce sulphur emissions. Simple systems are easy to maintain. No

fuel costs. Renewable.

Expensive to set up. Expensive drilling through hot rocks. Limited areas in the world where hot areas are close to the

surface.

BiomassProduces no long term C02. Renewable as trees can be

regrown

Limited areas of land available. Reduces the production of food.

Solar Heating

Produce no C02. Renewable. Light is free.

Unreliable as the sun does not shine all the time. No sun at night.

Solar (Photovolta

ic) Cells

Produce no C02. Renewable. Light is free. Can be small to be

used instead of batteries.

Unreliable as the sun does not shine all the time. No sun at night. Expensive to

set up.

Section 5: Solids, liquids and gases

a) Units

use the following units: degrees Celsius (°C), kelvin (K), joule (J), kilogram (kg), kilogram/metre3 (kg/m3), metre (m), metre2 (m2 ), metre3 (m3), metre/second (m/s), metre/second2 (m/s2 ), newton (N), pascal (Pa).

b) Density and pressure

know and use the relationship: density = mass / volume ρ = m / V

describe experiments to determine density using direct measurements of mass and volumeDensity of a regular solid• Measure the mass using a balance• Measure the width, length and height using a ruler• Calculate volume (V = w x l x h)• Calculate density (ρ = m/V)

Density of a liquid1 Measure mass of empty measuring cylinder using a balance2 Measure mass of liquid and measuring cylinder3 Subtract 1. from 2. to calculate the mass of the liquid4 Measure volume of liquid (using measuring cylinder)• NB: measure to the bottom of the meniscus5 Calculate density (ρ = m/V)

Density of an irregular solid1 Measure mass using balance2 Measure volume using the ‘displacement’ method(submerge solid in ‘Eureka can’ and measure overflow)3 Calculate density (ρ = m/V)

know and use the relationship: pressure = force / area p = F / Aunderstand that the pressure at a point in a gas or liquid which is at rest acts equally in all directionsknow and use the relationship: pressure difference = height × density × g p = h × ρ × g

c) Change of state

understand the changes that occur when a solid melts to form a liquid, and when a liquid evaporates or boils to form a gas

describe the arrangement and motion of particles in solids, liquids and gasesSolid: low energy; little movement, vibrating on the spotLiquid: some energy; some movement; particles collide, bouncing apart and creating space between particlesGas: lots of energy; lots of movement; particles collide a lot, bouncing apart more creating lots of space between particles

d) Ideal gas molecules

understand the significance of Brownian motion, as supporting evidence for particle theoryunderstand that molecules in a gas have a random motion and that they exert a force and hence a pressure on the walls of the containerunderstand that there is an absolute zero of temperature which is – 273oC

describe the Kelvin scale of temperature and be able to convert between the Kelvin and Celsius scalesThe kelvin temperature scale uses absolute zero as a starting point.Absolute zero is 0 Kelvin.Absolute zero is -273°C0 kelvin = -273°C273 Kelvin = 0°C1 Kelvin = -272°C274 Kelvin = 1°C

understand that an increase in temperature results in an increase in the speed of gas moleculesunderstand that the Kelvin temperature of the gas is proportional to the average kinetic energy of its molecules

describe the qualitative relationship between pressure and Kelvin temperature for a gas in a sealed containerAs Kelvin increase, energy increases. As the energy of something increases, its particles will move faster and with more force. This will mean more force is exerted over a fixed area- increasing pressure.So if a gas has its kelvin increased, it will exert more force on the container its in, meaning the pressure will go up.

use the relationship between the pressure and Kelvin temperature of a fixed mass of gas at constant volume:p1 / T1 = p2 / T2

use the relationship between the pressure and volume of a fixed mass of gas at constant temperature:p1V1 = p2V2

Section 7: Radioactivity and particles

a) Units

use the following units: becquerel (Bq), centimetre (cm), hour (h), minute (min), second (s).

b) Radioactivity

describe the structure of an atom in terms of protons, neutrons and electrons and use symbols such as 146C to

describe particular nucleiAn atom consists of a small central nucleus composed of protons and neutrons surrounded by electrons. An atom will always have the same number of electrons as protons.

understand the terms atomic (proton) number, mass (nucleon) number and isotopeThe atomic number of an atom is equal to the number of protons in it’s nucleusThe mass number of an atom is equal to the number of protons+neutrons in its nucleusIsotopes are atoms of the same element with different numbers of neutrons

understand that alpha and beta particles and gamma rays are ionising radiations emitted from unstable nuclei in a random process

describe the nature of alpha and beta particles and gamma rays and recall that they may be distinguished in terms of penetrating powerAn alpha particle consists of two protons and two neutrons. It is strongly ionisingA beta particle is a high speed electron. It is produced when a neutron has decayed into an electron and proton. It is moderately ionising.Gamma rays are very high frequency electromagnetic waves. They are produced when an unstable nucleus loses energy. They are weakly ionising.

describe the effects on the atomic and mass numbers of a nucleus of the emission of each of the three main types of radiationAlpha particles consist of two protons+two neutrons; mass number decreases by 4 & atomic number decreases by 2 Beta decay; mass number stays the same & atomic number increases by 1Gamma decay; mass number & atomic number stay the same

understand how to complete balanced nuclear equationsunderstand that ionising radiations can be detected using a photographic film or a Geiger-Muller detector

explain the sources of background radiation

understand that the activity of a radioactive source decreases over a period of time and is measured in becquerelsunderstand the term ‘half-life’ and understand that it is different for different radioactive isotopesuse the concept of half-life to carry out simple calculations on activity

describe the uses of radioactivity in medical and non-medical tracers, in radiotherapy and in the radioactive dating of archaeological specimens and rocksTracers- a radioactive source is put into a system (like a piping network), it will build up where there is a blockage a be detected, showing where a problem is.

Medical tracers- a radioactive source is put into a body and will build up at a blockage so an area of problem can be detected.

Radiotherapy- radiation is used to destroy unwanted cells (cancerous cells.)

Radioactive dating- aka carbon dating. The amount of radiation from an object is measured, the half life of the carbon is then used to see how old the object is. Archaeologists use this to tell the age of an object.

describe the dangers of ionising radiations, including:• radiation can cause mutations in living organisms• radiation can damage cells and tissue• the problems arising in the disposal of radioactive waste.and describe how the associated risks can be reduced.Radiation can cause mutations in living organisms: radiation can damdge the stucture of a cells DNA, when the cell replicates the changes (mutation) will be passed on; this can be how cancer is caused.

Radiation can damage cells and tissue: atoms can be change by radiation, this prohibits them functioning properly, this can mean cells and so tissue are damaged.

The problems arising in the disposal of radioactive waste: this waste emits radiation that, as shown above, can be dangerous. If the waste is put into water it can poison ecosystems, similarly with land. Radioactive waste tends to be buried under the ground; with the thinking that when it is much less harmful it can be dug up and disposed of.

c) Particles

describe the results of Geiger and Marsden’s experiments with gold foil and alpha particlesApha radiation was beamed at a sheet of gold foil, a sheet of zinc sulphide surrounding the foil showed where the alpha particles ended up; a few went straight through, many were deflected at angles, some were deflected straight back.

describe Rutherford’s nuclear model of the atom and how it accounts for the results of Geiger and Marsden’s experiment and understand the factors (charge and speed) which affect the deflection of alpha particles by a nucleusThe nuclear model of an atom is the one we all know: a central nucleus with positive protons and neutral neutrons surrounded by orbiting negative electrons.Before the Geiger Marsden experiment, the 'plum pudding' model of an atom was believed: a positive sphere contained negative electrons dotted inside. If this was true the alpha particles would have gone straight through the sheet of gold and all come out the other side.What actually happened was that some were deflected at different angles, this showed that the positive alpha particles were being repelled by a positive charge and others were going through the space between the charged areas. The faster they hit it the faster they were repelled. This is where the idea was formed of a nucleus and orbiting electrons.

understand that a nucleus of U-235 can be split (the process of fission) by collision with a neutron, and that this process releases energy in the form of kinetic energy of the fission productsunderstand that the fission of U-235 produces two daughter nuclei and a small number of neutronsunderstand that a chain reaction can be set up if the neutrons produced by one fission strike other U-235 nuclei

understand the role played by the control rods and moderator when the fission process is used as an energy source to generate electricity. In nuclear power stations, nuclei are split by having neutrons fired at them, these release other neutrons as well as a large amount of energy. The energy is used to create electricity, and the radioactive by-products are disposed of.Control rods can absorb neutrons. If there are two many neutrons the chain reaction could get out of control, so the control rods are lowered in to the reaction to absorb some neutrons and control the reaction.

The moderator slows neutrons down so that they are at the right speed to split nuclei, the moderator is usually graphite.