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Physics P1
Name: .....................................
Heat transfer
Explain, in terms of particles, how heat is transferred through the glass
wall of a boiling tube. (2 marks)
particles vibrate with a bigger / stronger amplitude / faster / with more
(kinetic) energy
energy transferred by collisions with other particles
accept particles vibrate more
do not accept start to vibrate only
do not accept answers in terms of free/mobile electrons
Explain how heat is transferred by the process of convection from the gas
flame at the bottom of the oven to the potatoes at the top of the oven. (3
marks)
any three from:
 (air) particles / molecules / atoms
gain energy
 (air) particles / molecules / atoms move faster
 (air) particles / molecules / atoms move apart
 air expands
 air becomes less dense
 warm/hot air rises
do not accept heat rises
If the potatoes need to be kept hot, they may be wrapped in shiny
aluminium foil.
Why does this help to keep the potatoes hot? (1 mark)
(foil) reflects heat (back towards potato)
or
(foil) is a poor emitter (of heat radiation)
The outside surface of a fridge-freezer is white and shiny.
Give two reasons why this type of surface is suitable for a fridge-freezer.
(2 marks)
any two from:
 poor absorber of heat /
radiation
 reflects heat / radiation (from room away from fridge-freezer )
 reduces heat transfer into the fridge-freezer
 reduces power consumption of fridge-freezer
Explain why the vacuum between the glass walls of the flask reduces heat
transfer by conduction and convection. (2 marks)
because there are no particles in a vacuum
conduction and convection need particles / medium
Why is a layer of fleece good at reducing the transfer of heat from a
skier’s body? (1 mark)
traps (small pockets of) air
Explain, in terms of the particles in the metal, how heat is transferred
through the radiator. (2 marks)
free / mobile electrons gain (kinetic) energy
free electrons collide with other (free) electrons / ions / atoms / particles
A central heating system has several radiators joined together. The hot water
goes from the boiler, through each radiator in turn and then back to the boiler
for reheating.
Give one reason, other than appearance, why it might not be a good idea to
paint radiators black. (1 mark)
any one from:
 transfer a lot of heat (too rapidly)
 water temperature drops too rapidly
 water too cold for the next radiator
Why is the inside of a vacuum flask shiny? (1 mark)
To reflect thermal energy back into the liquid.
Use the kinetic theory to explain why liquids can flow. (2 marks)
Particles are not in a fixed position, so they can move past each other.
Explain how a thermometer works. (2 marks)
When a thermometer is put into something hot, particles in liquid gain more
energy, move more quickly, and so expand. The only place liquid can go is up the
narrow tube. Opposite for when a thermometer is used to measure a cooler
temperature.
Describe what happens to the particles in a gas as the temperature
increases. (2 marks)
Particles gain more energy so they move faster and collide with each other more
often. They take up more room.
Explain how free electrons transfer heat in a metal. (2 marks)
Metals contain free electrons which are free to move; free electrons can
transfer thermal energy.
Why are liquids and gases poor thermal conductors. (2 marks)
The particles in a liquid are not in a regular arrangement, and in a gas they are
too far apart.
An ice cube is placed in a glass of water. In terms of energy and particles,
explain why the water beneath the ice cube begins to sink. (2 marks)
Convection. The particles in the water have less energy so move more slowly,
increasing the density of the fluid, which causes it to sink.
Describe how evaporation can be used to keep things cool and give an
example. (2 marks)
By keeping them damp, thermal energy will be lost through evaporation. Object
needs to be left in the shade – not in direct sunlight.
Explain how a tumble dryer dries dark clothes. (2 marks)
Increases rate of evaporation by adding thermal energy and increasing flow of
air.
How could you reduce the rate of heat energy transfer from a hot drink?
(2 marks)
Put it in an insulated cup (which reduces heat transfer from conduction and
convection) and put a lid on it (which reduces heat transfer by evaporation).
What can you say about the rate of heat energy transfer in an object that
is at the same temperature as its surroundings? (2 marks)
The rate of heat energy transferred into the object is the same as the rate of
heat energy transferred out of the object.
Why should you fill up a vacuum flask rather than half fill it? (1 mark)
The rate of heat energy transferred into the object is the same as the rate of
heat energy transferred out of the object.
Wood has a high specific heat capacity. Why would you not use it in a
heater? (2 marks)
It is a poor conductor of heat and it cannot transfer heat by convection or
radiation.
Electric kettles are found in most kitchens. Electric kettles are designed to
transfer energy from electricity into heat. The energy is used to boil
water.
Most modern kettles have an automatic ‘cut-off’ switch which turns the
kettle off when all the water in it has boiled.
Explain how the kettle boils all of the water before it switches off. Use
ideas about energy transfer by heating and kinetic theory in your answer.
(6 marks)
Examples of scientific points made in the response:
Resistance to electric current in element increases heat energy and / or kinetic
energy of particles.
Increased collisions pass energy
through element.
Heat conducted into water from element. Water in contact with element gains
heat / temperature rises;
Becomes less dense;
Particles further apart
Water rises due to lower density.
Cooler water falls and replaces warmer
water in contact with the element .
Warmer particles transfer energy to surroundings as rise ;
Setting up convection currents.
Water boils as all reaches same temperature.
Energy
Explain why using an energy-efficient light bulb instead of an ordinary light
bulb reduces the amount of carbon dioxide emitted into the atmosphere. (2
marks)
less electricity / energy to be generated / needed from power stations
reduction in (fossil) fuels being burnt
accept less demand
accept correctly named fuel
accept answer in terms of:
fewer light bulbs required because they last longer (1 mark)
less energy used / fuels burnt in production / transport etc. (1 mark)
ignore reference to CO2 or global warming
ignore reference to conservation of energy
A student thinks that because energy cannot be destroyed it is not possible
to waste energy. So he leaves his radio, TV and computer on all the time,
even when there is no one in the house.
Explain why he is wrong about not being able to waste energy. (2 marks)
any two from:
 energy not usefully transformed is
wasted e.g. not listened to
 (wasted and useful) energy transferred to surroundings
 (energy spreads out) and is difficult to use usefully for further energy
transformations
accept specific examples of energy wasted by any named appliances
do not accept machines not 100 % efficient on its own
What is meant by an energy source being renewable? (1 mark)
will never run out
do not accept can be used again
What happens to the wasted energy? (1 mark)
Gets dissipated
transferred to surroundings / atmosphere
or
becomes spread out
‘Replacing an old freezer with a new ‘A’ rated freezer will benefit the
environment.’
Do you agree that replacing the freezer will benefit the environment?
Answer yes or no. Explain the reasons for your answer. (2 marks)
yes plus explanation
 less electricity / energy needed / used
 less (fossil) fuels burned
less polluting gases emitted
or
no plus explanation
• old freezer must be disposed of
• hazardous chemicals inside freezer
• (lot of) energy used in producing new freezer
the marks are for the explanation
accept less energy wasted
accept a named fossil fuel
do not accept conserving (fossil) fuels
accept a named polluting gas / greenhouse gases / carbon emissions / reduce
global warming
accept an answer in terms of nuclear fuel
eg less nuclear fuel required (1) less nuclear waste (1) accept CFC gases

What happens to the energy wasted by the electric motor? (1 mark)
transferred to surroundings / surrounding molecules / atmosphere or
becomes dissipated / spread out
An ‘A’ rated washing machine is more energy efficient than a ‘C’ rated
washing machine.
Explain what being more energy efficient means. (2 marks)
a smaller proportion / percentage of the energy supplied is wasted
accept a statement such as ‘less
energy is wasted’ for 1 mark
do not accept costs less to run ignore references to uses less energy
Suggest why reducing the amount of energy used by washing machines could
reduce the amount of carbon dioxide emitted into the atmosphere. (1 mark)
any one from:
 less electricity needed
 fewer power stations needed
 less fuel is burned
Any device that transforms energy will waste energy.
Why must the total energy input to such a device always equal the total
energy output from the device? (1 mark)
energy cannot be destroyed
accept energy is conserved
Generating Electricity
What name is given to the network of cables and transformers that links
power stations to consumers? (1 mark)
National grid
What does a step-up transformer do? (1 mark)
increases voltage / potential difference
accept decrease current
accept step-up / boosts the voltage
do not accept increases energy / power / current
ignore reference to voltage going through
Explain why step-up transformers are used in the electricity distribution
system. (2 marks)
any two from:
• reduce current ignore increased voltage / pd
 reduces energy loss / power loss (from cables)
 increases efficiency (of distribution)
accept reduces heat loss
do not accept stops energy loss
Most of the world’s electricity is generated in power stations that burn
fossil fuels. State one environmental problem that burning fossil fuels
produces. (1 mark)
any one from:
 produces pollutant gases
 produces solid waste / ash / smoke
accept produces carbon dioxide / sulfur dioxide / nitrogen oxides accept global
warming / greenhouse effect / carbon emissions / air pollution / acid rain
ignore ozone layer
do not accept carbon monoxide accept global dimming
ignore produces pollution
What arguments could a company give to persuade people that a wind farm
is a good idea? (2 marks)
any two from:
 using renewable energy
 make non-renewable fuels last longer
 non-renewable fuels can be used for other processes
 no pollutant gases produced
 land can still be used for farming
any two valid points gains the marks
accept don’t use up non-renewable / fossil fuels
accept named fuels, ignore no pollution, ignore economic issues
What reasons may be given by the people who think that wind farms are
not a good idea? (2 marks)
any two from:
 cause noise pollution
 cause visual pollution
 may interfere with TV / radio / mobile phone signals
 need to put in new infrastructure
 not reliable owtte
 dangerous to birds
 lots of concrete needed for the bases or
producing cement is environmentally damaging
accept spoils the landscape accept sunlight flicker
accept new roads needed
accept reduces house prices
ignore any references to cost / jobs / number required
ignore takes up a lot of land
accept reference to obstruction of shipping etc. if clear reference to offshore
wind farm
Outline the arguments that a scientist working in the nuclear power industry
could use to justify the building of more nuclear power stations in the
future. (3 marks)
only accept answers in terms of the argument of the nuclear power scientist any
three from:
 produces a lot of energy for a small mass of fuel or is a concentrated
energy source
 it is reliable or it can generate all of the time
 produces no pollutant gases
 produces only a small volume of
(solid) waste
 advances in technology will make fuel reserves last much longer
accept amount for mass
accept named gas or greenhouse gases do not accept no pollution
accept amount for volume
accept an argument in terms of supply and demand
Nuclear waste is a problem that must be dealt with. One possible solution
would be to bury the waste deep underground. Suggest one reason why
some people are against burying nuclear waste. (1 mark)
 may leak into the ground / environment
 geological changes
 may get into the food chain
 over time if location not correctly recorded it may be excavated
accept earthquakes etc, do not accept answers in terms of property prices or
‘damages the environment’
Suggest why, apart from the declining reserves of fossil fuels, power
companies should use more bio-fuels and less fossil fuels to generate
electricity. (3 marks)
any three from:
 carbon neutral so overall add no carbon dioxide to
the environment
 power companies can sell electricity at a higher price
 opportunity to grow new type crop
 more jobs
 more land cultivated or different types of land utilised
accept do not add to global warming accept they are carbon neutral
accept power companies make more profit
accept specific examples e.g. growing plants in swamps
accept extends the life of fossil fuel reserve
Although there are some risks associated with nuclear power stations, it is
likely that new ones will be built.
Give two reasons to justify the use of nuclear power. (2 marks)
any two from:
 produce no pollutant / harmful
gases
 produces a lot of energy for a small mass (of fuel) or
is a concentrated energy source
 it is reliable or
it can generate all of the time
 produces only a small volume of (solid) waste
answers should be in terms of nuclear power and not why we should not use
other fuels
accept named gas or greenhouse gases do not accept no pollution
accept amount for mass accept high energy density
accept amount for volume
Name the process by which a nuclear fuel provides the energy needed to
generate electricity in a nuclear power station. (1 mark)
Nuclear fission
Transformers are part of the National Grid. Transformers are efficient devices.
What is meant by a device being efficient ? (1 mark)
small proportion of energy / power is wasted
or
transfers most / more / a lot of energy power usefully
accept little / less energy / power / heat is wasted
do not accept it wastes no energy / power
When electricity flows through a cable, some energy is transformed into
heat. Explain how the National Grid system reduces the amount of energy
lost as heat. (2 marks)
it decreases the current / uses low current
or
it increases the voltage / potential difference
or
uses high voltage / potential difference
smaller the current the smaller the energy loss
Explain why leaving appliances on standby damages the environment.(2
marks)
any two from:
 (more) electricity needs to be
generated
 (more) power stations needed
 (more) fossil fuels burnt
 (more) pollutant gases emitted
Explain how the heat released from a nuclear fuel is used to generate
electricity in power stations. (2 marks)
water heated to produce (high pressure) steam
steam turns turbine which drives generator
Nuclear power stations create dangerous waste.
Why is the waste from a nuclear power station dangerous? (1 mark)
it is / can be radioactive
or
emits radiation (from the nuclei)
do not accept answers in terms of kills cells / cancer
Explain the possible link between climate change and coal-burning power
stations. (2 marks)
coal (burning) power stations / burning coal produces carbon dioxide
(increased) CO2 increases / contributes to / causes global warming / greenhouse
effect
Explain how the step-up transformer increases the efficiency of the
National Grid. (2 marks)
decreases the current
reducing energy loss (along cables)
The electricity used in homes in the UK is normally generated in a fossil
fuel power station. Outline some of the advantages of using solar cells to
generate this electricity. (2 marks)
 produce no / less (air)
pollution
 energy is free
 (energy) is renewable
 conserves fossil fuel stocks
 can be used in remote areas
 do not need to connect to the
National Grid
The power output from a conventional large-scale hydroelectric power
station is 100000 times more than the power output from a microhydroelectric system.
Give one disadvantage of a conventional large-scale hydroelectric power
station compared to the micro-hydroelectric system. (1 mark)
any one from:
 large areas of land are
flooded
 peoples homes may be destroyed
 habitat (of animals and plants) lost / damaged
Explain why transferring the electricity directly to local homes is more
efficient than using the National Grid to distribute the electricity. (2
marks)
less energy loss / wasted (in the cables)
as the cables are shorter
What are the differences between a conventional power station and a
geothermal power station? (2 marks)
Different sources of thermal energy to heat water to turn it into steam to drive
the turbines. In some geothermal power stations, steam from under the ground
can be used to drive turbines directly. Conventional uses coal, oil or natural gas.
What is the function of the cooling towers? (1 mark)
To condense steam back into water.
Why is it important that natural gas power plants have a short start up
time? (1 mark)
To provide extra electricity if there is a sudden increase in demand.
Explain the process of carbon capture and give an example of where carbon
dioxide might be stored. (2 marks)
The CO2 produced by burning fossil fuels is not released into the atmosphere.
Instead, it is ‘captured’ and stored. Examples of storage sites include old oil and
gas fields.
List some of the disadvantages of using fossil fuels to generate electricity.
(3 marks)
Burning fossil fuels releases CO2 into the atmosphere (or other named form of
atmospheric pollution). Fuels need to be mined/extracted and then transported
to power stations. Visual pollution.
Is nuclear power a renewable or non renewable energy resource? Explain
your answer. (2 marks)
Non-renewable – we will eventually run out of uranium (although this will happen
a long time in the future).
State the energy changes inside a nuclear power plant (ending with
electrical energy from the generator) (2 marks)
Nuclear energy  heat (or thermal)  kinetic  electrical
Describe how nuclear reactors can be used to generate electricity. (2
marks)
A nuclear reaction produces heat. This heat turns water to steam. The steam
turns a turbine which turns a generator which generates electricity.
Describe the similarities and differences between biofuels and fossil fuels.
(4 marks)
Similarities: both involve burning fuel derived from living organisms; both can be
used to generate electricity (and the process is very similar).
Differences: the organisms which formed fossil fuels died millions of years ago;
fossil fuels are generally a more concentrated form of chemical energy; biomass
is carbon neutral; biomass is a renewable energy resource.
Explain why biomass is described as carbon neutral. (2 marks)
There is no increase of CO2 in the atmosphere. Burning biomass only releases
the CO2 that the plant absorbed when it was growing.
Solar cells are used to provide electricity for garden lights. What is needed
so that the lights can come on at night? (1 mark)
Something to store the energy/ such as a cell/battery
Why is electricity stepped up before being distributed by the national grid?
(1 mark)
Energy losses from the high current would be much bigger; the cable would burn
out.
Why is electricity stepped down before it enters the home? (2 marks)
So it is safe to use; electrical devices are designed to be used at 230 V.
The picture shows one type of solar water heater. Water from the tank is
slowly pumped through copper pipes inside the solar panel where the water
is heated by energy from the Sun. The water in the tank could be heated
by using an electric immersion heater.
Outline the advantages and the disadvantages of using solar energy to heat
the water rather than using an electric immersion heater. (6 marks)
Advantages:
Renewable energy source
Energy is free
Does not pollute the atmosphere
No fuel is burnt
Energy can be stored in water
Disadvantages:
Only available in daylight
Availability fluctuates
Insufficient hours of sunlight in some countries
Average low intensity in some countries
Over the next 10 years, more than 300 kilometres of new high voltage
transmission
cables are to be added to the National Grid. Most of the new cables will be
suspended from pylons and run overhead while the rest will be buried
underground.
Outline the advantages and disadvantages of both overhead transmission
cables and
underground transmission cables. (6 marks)
Overhead advantages:
- quick/easy to repair/access
- less expensive to install/repair/maintain
-cables cooled by air
- air acts as insulator
- can use thinner cables
Overhead disadvantages
- spoil the landscape
- greater risk of electric shock
- damaged/affected by severe weather
- hazard to low flying aircraft/helicopters
Underground advantages:
- cannot be seen
- no hazard to aircraft/helicopters
- unlikely to be damaged by severe weather
- reduced shock hazard
Underground disadvantages:
- repairs take longer/more expensive
- more difficult to access
- very expensive to install
- thicker cables required
- need cooling systems
- need layers of electrical insulation
- land disruption
Waves
What is gamma radiation? (1 mark)
electromagnetic (wave / radiation)
A student listens to the sound waves produced by a car siren. When the car
is stationary, the student hears a constant frequency sound.
Describe how the wavelength and frequency of the sound waves heard by
the student change when the car is driven away from the student. (2
marks)
wavelength increases accept the crests are further apart ignore waves are
further apart
frequency decreases accept pitch decreases
ignore references to amplitude
Explain why living near a mobile phone mast could cause ill health. (3 marks)
emit / uses / transmit / receive microwaves
some microwave / energy absorbed by / enters the body
raises temperature of (body) cells / tissue / water
any mention of alpha, beta, gamma waves scores 0 marks
accept radiation for microwaves throughout
ignore radio waves
ecf for their given electromagnetic wave
do not accept goes through the body accept reference to water molecules
vibrating faster
accept it could cause mutation / harm / kill cells
do not accept answers in terms of ionisation
ignore references to cancer
A person has naturally dark skin. Suggest why he can sunbathe with less
risk of getting skin cancer than a fair- skinned person. (2 marks)
more UV / radiation absorbed by dark skin
less UV penetrates deep to damage (living) cells / tissue
accept darker skin has more melanin / pigment
do not accept sunlight or heat for ultraviolet
Most people know that sunbathing can cause skin cancer. But most
holidaymakers still like to come home with a suntan.
Why is it important that people understand that there are dangers involved
in sunbathing? (1 mark)
so people can make up their minds about the potential risk to their
health.
accept ̈so people know to take precautions
Visible light travels through air at 300 000 000 m/s.
Why can we assume that radio waves travel through air at the same speed
as light?
all electromagnetic waves travel at the same speed through a vacuum, (so
assume same speed in air)
Who is likely to be exposed to more ultraviolet radiation, a skier or a
golfer? Draw a ring around your answer. A skier or a golfer
Give a reason for your answer. (2 marks)
skier
exposed to high(er) level reflected UV or
less UV absorbed by the atmosphere
golfer
out when Sunís intensity is highest
or
larger area of skin / body exposed
accept radiation for UV
accept snow is a good reflector of UV do not accept snow reflects UV
accept snow is a poor absorber of UV do not accept snow absorbs UV
accept when Sun is stronger / hotter accept golfer is outside for longer
Some scientists think that there is a link between using a mobile phone and
some types of illness. Other scientists disagree. They say that the evidence
is limited and unreliable. Suggest what scientists could do to show a link
between using a mobile phone and illness. (1 mark)
compare (the health of) mobile phone users with non-mobile phone users
How could scientists improve the reliability of the evidence? (1 mark)
Repeat/increase sample size
Devices designed to protect a mobile phone user from microwave radiation
are now available. Why is it important that these devices are tested by
scientists who are not working for the company that makes the devices? (1
mark)
any one from:
 to get an independent
opinion
 company scientists may be biased
What is meant by the term radioactive? (1 mark)
substances that give out radiation
Which type of electromagnetic wave has a lower frequency than
microwaves? (1 mark)
Radio waves
What do all types of electromagnetic wave transfer from one place to
another? (1 mark)
Energy
Microwaves and visible light are two types of electromagnetic wave. Both
can be used for communications. Give two properties that are common to
both visible light and microwaves. (2 marks)
any two from:
 travel at the same speed (through a vacuum)
 can travel through a vacuum / space
 transfer energy
 can be reflected
 can be refracted
 can be diffracted
 can be absorbed
 can be transmitted
 transverse
Name two more types of electromagnetic wave that can be used for
communications. (2 marks)
infra red
radio(waves)
What type of wave is used to send information to and from satellites? (1
mark)
Microwaves
What property of this type of wave makes it suitable for satellite
communications? (1 mark)
Can pass through ionosphere
In 2009, parts of the African country Kenya, were linked to the Internet
by a super-fast optical fibre. Before that, all Internet connections had to
be made via a satellite link.
Complete the following sentence.
Signals can be sent along an optical fibre using either visible light or Microwaves
Microwaves and radio waves are both part of the electromagnetic spectrum.
How are microwaves different from radio waves? (1 mark)
higher frequency or shorter wavelength or greater energy
How fast do microwaves travel through the air or a vacuum compared to
radio waves? (1 mark)
Same speed
As the loudspeaker moves towards the students, the frequency of the note
heard by the students increases.
What happens to the note heard by the students as the loudspeaker moves
away from them? (1 mark)
frequency / pitch decreases accept wavelength increases accept it
Describe how a string could be used to demonstrate transverse and
longitudinal waves. (2 marks)
Vibrate one end of the spring (the other end should be fixed). Moving the
vibrating end in the same direction as the spring, creates a longitudinal wave.
Moving the end at 90° to the spring creates a transverse wave.
Describe how a speaker produces compressions and rarefactions. (2 marks)
The cone moves in and out. When it moves out, it creates a compression; when it
moves back in, it creates a rarefaction.
Explain why in some valleys you can’t get a TV signal but you can pick up
longer wavelength radio signals. (2 marks)
The longer the wavelength the greater the diffraction. Radio waves have a
longer wavelength than TV waves and so when they travel around obstacles (like
hills); they diffract more. This allows the signal to reach the bottom of some
valleys. TV signals have a shorter wavelength and so they do not diffract as
much; the signal does not reach all parts of the valley.
Why are X-rays potentially hazardous and what measures, can be taken to
reduce the risks when using them? (2 marks)
They have a short wavelength (high frequency); this means they can transfer a
lot of energy and they are very penetrating. To reduce the risks from X-rays
you could limit your exposure time or wear shielding (lead-lined apron).
Explain why TV signals are generally a shorter wave length than radio
signals? (2 marks)
More information needs to be sent in a TV signal (pictures and sound).
Therefore shorter wavelengths are used.
Describe what causes the Doppler effect. (2 marks)
When the wave source moves towards a listener/receiver the waves are bunched
up. This causes an increase in frequency/decrease in wavelength. When the wave
source moves away from the listener/receiver the opposite happens.
Explain what would happen to the change in pitch if the F1 car was moving
much faster. (2 marks) It would be more noticeable; the sound would be of
much higher pitch as the car moved towards the observer, and much lower pitch
as it moved away.
Earth
Satellites fitted with various telescopes orbit the Earth. These telescopes
detect different types of electromagnetic radiation.
Why are telescopes that detect different types of electromagnetic waves
used to observe the Universe? (1 mark)
stars / galaxies / sources emit all / accept two or more named different types
of electromagnetic waves / electromagnetic waves radiation
accept answers in terms of frequencies / wavelengths
In 2005 a space telescope detected a star that exploded 13 billion years
ago. The light from the star shows the biggest red-shift ever measured.
What is red-shift? (1 mark)
wavelength (of light) increases accept frequency decreases
or
light moves to red end of spectrum accept redder but do not accept red
alone
What does the measurement of its red-shift tell scientists about this star?
(1 mark)
it is the star (detected) furthest from the Earth
or
it is moving away the fastest
Red-shift provides evidence for the ‘big bang’ theory. Describe the ‘big
bang’ theory. (2 marks)
all matter compressed to / starts at / comes from a single point
(massive) explosion sends matter outwards
do not accept increasing gravitational pull
accept everything / the universe for all matter
accept explosion causes universe to expand
ignore explosion creates the universe or further reference to star / Earth
formation
Suggest what scientists should do if new evidence were found that did not
support the ‘big bang’ theory. (1 mark)
check validity / reliability of the evidence
or
change the theory to match the new accept comparison of new and old evidence
evidence
Explain how the spectrum ‘shift’ of the dark line supports the theory that
the Universe began from a very small point. (3 marks)
line shifts towards red end of spectrum
wavelength (appears) to increase
galaxy is moving away (from the Earth)
or
galaxy moving away from initial point
do not accept reference to ëred lightí do not accept ëred shiftí as a stand
alone response
do not accept universe expanding do not accept planet on its own
The ‘steady state’ theory was once a popular alternative to the ‘big bang’
theory.
The ‘steady state’ theory suggested that the universe, although expanding,
had no origin and it has always existed. As the universe expands, a small
amount of matter is created to keep the universe looking exactly the same
all of the time.
(a) When considering the origin of the universe, what is the difference
between the ‘big bang’ theory and the ‘steady state’ theory?
big bang theory - universe started at one point (then expanded)
steady state theorỹ - universe has no origin / has always existed
The light from distant galaxies shows a red-shift. What is red-shift? (1
mark)
wavelength (of light) increases
or
wavelength / light moves to red end of spectrum
accept answers in terms of frequency decrease
accept wavelength stretched but not wave stretched
do not accept galaxy moves to the red end of the spectrum
do not accept light becomes red / redder
Why does red-shift provide evidence to support both the ‘big-bang’ theory
and the ‘steady state’ theory? (2 marks)
red-shift is evidence / supports idea of expanding universe
both theories use the idea / accept / explain why the universe is expanding
The ‘steady state’ theory was important in encouraging new research into
the universe. Suggest a reason why scientists were keen to carry out new
research. (1 mark)
to find evidence to support one or both theories
or
to find evidence to disprove one or both theories
accept prove for support
accept to gain more knowledge about the universe
Scientists can answer many questions about the universe, but not the
question:
‘Why was the universe created?’
Suggest a reason why this question cannot be answered by scientists. (1
mark)
answer involves (religious) belief
accept it cannot be tested
or
no / insufficient evidence
The ‘Big Bang’ theory is one theory of the origin of the Universe. Explain
what is meant by the ‘Big Bang’ theory. (2 marks)
Universe began at a (very) small (initial) point
‘explosion’ sent matter outwards
or
‘explosion’ causing Universe to expand
The light arriving from distant galaxies provides scientists with evidence to
support the ‘Big Bang’ theory. Explain how. (2 marks)
light shows a red shift
galaxies moving away (from the Earth)
At a meeting held in 2005, a group of scientists claimed that new data had
been collected that showed the ‘Big Bang’ theory to be wrong. Other
scientists said that there was no reason to doubt the ‘Big Bang’ theory.
What should scientists do when a theory does not appear to be supported
by new data? (2 marks)
check reliability / validity of data
amend theory
or
discount the data
accept check data accept collect more data
accept replace old theory with new theory
The Ancient Greeks believed that the Universe went on forever ; it never
changed and had no beginning. It had always existed.
How are the ideas put forward by the big bang theory different from the
beliefs of the Ancient Greeks? (2 marks)
Universe had a start point
Universe is (still) changing / expanding
Describe what scientists have noticed about the red shift from galaxies
further away from us and explain what this means about those galaxies. (2
marks)
The red-shift is greater; this means the galaxy is moving away faster.
What would happen to the light observed from a galaxy that was moving
towards us? Suggest a name for this effect. (2 marks)
Light from galaxies moving towards us would be compressed (its wavelength
would decrease). This might be called blue- or violet-shift.
Explain the origin of cosmic background radiation. (2 marks)
The heat left over from the Big Bang. As the Universe has expanded it has
cooled, and this heat is in the microwave region of the electromagnetic
spectrum.
Explain why the Big Bang theory is at present the most widely accepted
theory on the origin of the Universe. (1 mark)
It is the only theory that explains the origin of cosmic microwave background
radiation.
How is the red shift used to support the Big Bang theory? (2 marks)
Further away galaxies are moving fastest; this suggests that the Universe is
expanding.
Current evidence suggests that the universe is expanding. Most scientists
currently believe that the universe began with a huge explosion called the
Big Bang. Describe how observed evidence supports this theory. (6 marks)
Examples of scientific points made in the response:
If a wave is moving relative to the observer there will be a change in the
observed wavelength
And/or frequency
Increase in wavelength of light from distant galaxies
Further away the galaxy, the faster it is moving
And bigger observed increase in wavelength
This is called ‘red shift’
Observed red shift supports big bang theory