C2 Question Booklet

This booklet helps you with 6 mark questions for the C2 paper

http://www.scribd.com/doc/216286548/C2-Assessment-Booklet

B2 Revision Powerpoint

This powerpoint covers the main parts of B2

http://www.scribd.com/doc/216286213/Revise-B2-in-20-Mins

Climate Change

Global warming: http://www.youtube.com/watch?v=Z_jHP6xBLe8

The Greenhouse effect: http://www.youtube.com/watch?v=NFXR49hg8II

Sea levels: http://www.bbc.co.uk/learningzone/clips/evidence-for-global-warming-sea-level-change-no-narration/1496.html 

Electromagnetic Spectrum rap

This covers the 7 types of EM wave you need to remember for P2, and gives some of their uses. There's even a little bit about revision at the end: http://www.youtube.com/watch?v=A0un-_jBPPU

P1 Specification

Module P1: The Earth and the Universe

P1.1 What do we know about the place of the Earth in the Universe?

1. recall that the Earth is one of eight planets moving in almost circular paths round the Sun

which, together with other smaller objects orbiting the Sun (asteroids, dwarf planets, comets)

and moons orbiting several planets, make up the solar system

2. describe the principal differences between planets, moons, the Sun, comets and asteroids

including their relative sizes and motions

3. understand that the solar system was formed over very long periods from clouds of gases and

dust in space, about five thousand million years ago

4. recall that the Sun is one of thousands of millions of stars in the Milky Way galaxy

5. recall that there are thousands of millions of galaxies, each containing thousands of millions of

stars, and that all of these galaxies make up the Universe

6. put in order and recall the relative sizes of: the diameters of the Earth, the Sun, the Earth’s

orbit, the solar system, the Milky Way, the distance from the Sun to the nearest star, and the

distance from the Milky Way to the nearest galaxy

7. understand that all the evidence we have about distant stars and galaxies comes from the

radiation astronomers can detect

8. recall that light travels through space (a vacuum) at a very high but  finite speed, 300 000 km/s

9. recall that a light-year is the distance travelled by light in a year

10. understand that the [1] nite speed of light means that very distant objects are observed as they

were in the past, when the light we now see left them

11. understand how the distance to a star can be measured using parallax (qualitative idea only)

12. understand how the distance to a star can be estimated from its relative brightness

13. understand that light pollution and other atmospheric conditions interfere with observations of

the night sky

14. explain why there are uncertainties about the distances of stars and galaxies with reference

to the nature and difficulty of the observations on which these are based and the assumptions

made in interpreting them

15. understand that the source of the Sun’s energy is the fusion of hydrogen nuclei

16. understand that all chemical elements with atoms heavier than helium were made in stars

17. understand that the redshift in the light coming from them suggests that distant galaxies

are moving away from us

18. understand that (in general) the further away a galaxy is, the faster it is moving away

from us

19. understand how the motions of galaxies suggests that space itself is expanding

20. recall and put in order the relative ages of the Earth, the Sun, and the Universe

21. recall that scientists believe the Universe began with a ‘big bang’ about 14 thousand million

years ago

22. understand that the ultimate fate of the Universe is dif[1] cult to predict because of difficulties in

measuring the very large distances involved and the mass of the Universe, and studying the

motion of very distant objects.

P1.2 What do we know about the Earth and how it is changing?

1. understand how rocks provide evidence for changes in the Earth (erosion and sedimentation,

fossils, folding)

2. understand that continents would be worn down to sea level by erosion, if mountains were not

being continuously formed

3. understand that the rock processes seen today can account for past changes

4. understand that the age of the Earth can be estimated from, and must be greater than, the

age of its oldest rocks, which are about four thousand million years old

5. understand Wegener’s theory of continental drift and his evidence for it (geometric [1] t of

continents and their matching fossils and rock layers)

6. understand how Wegener’s theory accounts for mountain building

7. understand reasons for the rejection of Wegener’s theory by geologists of his time (movement

of continents not detectable, too big an idea from limited evidence, simpler explanations of the

same evidence, Wegener an outsider to the community of geologists)

8. understand that sea floor spreading is a consequence of movement of the mantle (convection

due to heating by the core)

9. recall that sea floors spread by a few centimetres a year

10. understand how sea floor spreading and the periodic reversals of the Earth’s magnetic field can explain the pattern in the magnetisation of sea floor rocks on either side of the

oceanic ridges

11. understand that earthquakes, volcanoes and mountain building generally occur at the edges

of tectonic plates

12. understand how the movement of tectonic plates causes earthquakes, volcanoes and

mountain building, and contributes to the rock cycle

13. recall that earthquakes produce wave motions on the surface and inside the Earth which can

be detected by instruments located on the Earth’s surface

14. recall that earthquakes produce:

a. P-waves (longitudinal waves) which travel through solids and liquids

b. S-waves (transverse waves) which travel through solids but not liquids

15. describe the difference between a transverse and longitudinal wave

16. understand how differences in the wave speeds and behaviour of P-waves and S-waves can

be used to give evidence for the structure of the Earth

17. in relation to waves, use the equation:

distance = wave speed × time

(metres, m) (metres per second, m/s) (seconds, s)

18. draw and label a diagram of the Earth to show its crust, mantle and core

19. recall that a wave is a disturbance, caused by a vibrating source, that transfers energy in the

direction that the wave travels, without transferring matter

20. recall that the frequency of waves, in hertz (Hz), is the number of waves each second that are

made by the source, or that pass through any particular point

21. recall that the wavelength of waves is the distance between the corresponding points on two

adjacent cycles

22. recall that the amplitude of a wave is the distance from the maximum displacement to the

undisturbed position

23. draw and interpret diagrams showing the amplitude and the wavelength of waves

24. use the equation:

wave speed = frequency × wavelength

(metres per second, m/s) (hertz, Hz) (metres, m)

25. understand that for a constant wave speed the wavelength of the wave is inversely

proportional to the frequency.

© OCR 2011 GCSE Science A

P2 Specification

Module P2: Radiation and Life

P2.1 What types of electromagnetic radiation are there? What happens when radiation hits an object?

1. interpret situations in which one object affects another some distance away in terms of a

general model of electromagnetic radiation:

a. one object (a source) emits radiation

b. the radiation travels outwards from the source and can be reflected, transmitted or

absorbed (or a combination of these) by materials it encounters

c. radiation may affect another object (a detector) some distance away, when it is absorbed

2. understand that light is one of a family of radiations called the electromagnetic spectrum

3. understand that a beam of electromagnetic radiation transfers energy in ‘packets’ called

photons

4. understand that the higher the frequency of an electromagnetic radiation, the more energy is

transferred by each photon

5. list the electromagnetic radiations in order of the energy transferred by each photon, or in

order of frequency:

radio waves, microwaves, infrared, red visible light violet, ultraviolet, X-rays, gamma rays

6. recall that all types of electromagnetic radiation travel at exactly the same, very high but finite,

speed through space (a vacuum) of 300 000 km/s

7. understand that the energy arriving at a square metre of surface each second is a useful

measure of the strength (or ‘intensity’) of a beam of electromagnetic radiation

8. understand that the energy transferred to an absorber by a beam of electromagnetic radiation

depends on both the number of photons arriving and the energy of each photon

9. understand that the intensity of a beam of electromagnetic radiation decreases with distance

from the source and explain why, in terms of the ever increasing surface area it reaches

and its partial absorption by the medium it travels through

10. understand that some electromagnetic radiations (ultraviolet radiation, X-rays, gamma rays)

have enough energy to change atoms or molecules, which can initiate chemical reactions

11. recall that high energy ultraviolet radiation, X-rays and gamma rays can cause ionisation

12. understand that the electromagnetic radiations which are ionising are those with high enough

photon energy to remove an electron from an atom or molecule (ionisation).

P2.2 Which types of electromagnetic radiation harm living tissue and why?

1. understand that the heating effect of absorbed radiation can damage living cells

2. relate the heating effect when radiation is absorbed to its intensity and duration

3. understand that some people have concerns about health risks from low intensity microwave

radiation, for example from mobile phone handsets and masts, though the evidence for this is

disputed

4. understand that some microwaves are strongly absorbed by water molecules and so can be

used to heat objects containing water

5. understand that the metal cases and door screens of microwave ovens reflect or absorb

microwave radiation and so protect users from the radiation

6. recall that some materials (radioactive materials) emit ionising gamma radiation all the time

7. understand that with increased exposure to ionising radiation, damage to living cells increases

eventually leading to cancer or cell death

8. understand that the ozone layer absorbs ultraviolet radiation, emitted by the Sun, producing

chemical changes in that part of the atmosphere

9. understand that the ozone layer protects living organisms from some of the harmful effects of

ultraviolet radiation

10. recall that sun-screens and clothing can be used to absorb some of the ultraviolet radiation

from the Sun

11. recall that physical barriers absorb some ionising radiation, for example: X-rays are absorbed

by dense materials so can be used to produce shadow pictures of bones in our bodies or of

objects in aircraft passengers’ luggage, and radiographers are protected from radiation by

dense materials such as lead and concrete.

P2.3 What is the evidence for global warming, why might it be occurring, and how serious a threat is it?

1. understand that all objects emit electromagnetic radiation with a principal frequency that

increases with temperature

2. recall that the Earth is surrounded by an atmosphere which allows some of the

electromagnetic radiation emitted by the Sun to pass through

3. recall that this radiation warms the Earth’s surface when it is absorbed

4. understand that the radiation emitted by the Earth, which has a lower principal frequency

than that emitted by the Sun, is absorbed or reflected back by some gases in the

atmosphere; this keeps the Earth warmer than it would otherwise be and is called the

greenhouse effect

5. recall that one of the main greenhouse gases in the Earth’s atmosphere is carbon dioxide,

which is present in very small amounts

6. recall that other greenhouse gases include methane, present in very small amounts, and

water vapour

7. interpret simple diagrams representing the carbon cycle

8. use the carbon cycle to explain:

a. why, for thousands of years, the amount of carbon dioxide in the Earth’s atmosphere

was approximately constant

b. that some organisms remove carbon dioxide from the atmosphere by photosynthesis

(eg green plants) and many organisms return carbon dioxide to the atmosphere by

respiration as part of the recycling of carbon

c. why, during the past two hundred years, the amount of carbon dioxide in the atmosphere

has been steadily rising

9. recall that the rise in atmospheric carbon dioxide is largely the result of:

a. burning increased amounts of fossil fuels as an energy source

b. cutting down or burning forests to clear land

10. understand that computer climate models provide evidence that human activities are

causing global warming

11. understand how global warming could result in:

a. it being impossible to continue growing some food crops in particular regions because of

climate change

b. more extreme weather events, due to increased convection and larger amounts of

water vapour in the hotter atmosphere

c. flooding of low lying land due to rising sea levels, caused by melting continental ice and

expansion of water in the oceans.

P2.4 How are electromagnetic waves used in communications?

1. understand that electromagnetic radiation of some frequencies can be used for transmitting

information, since:

a. some radio waves and microwaves are not strongly absorbed by the atmosphere so can

be used to carry information for radio and TV programmes

b. light and infrared radiation can be used to carry information along optical fibres because

the radiation travels large distances through glass without being significantly absorbed

2. recall that information can be superimposed on to an electromagnetic carrier wave, to create a

signal

3. recall that a signal which can vary continuously is called an analogue signal

4. recall that a signal that can take only a small number of discrete values (usually two) is called

a digital signal

5. recall that sound and images can be transmitted digitally (as a digital signal)

6. recall that, in digital transmission, the digital code is made up from just two symbols, ‘0’ and ‘1’

7. understand that this coded information can be carried by switching the electromagnetic carrier

wave off and on to create short bursts of waves (pulses) where ‘0’ = no pulse and ‘1’ = pulse

8. recall that when the waves are received, the pulses are decoded to produce a copy of the

original sound wave or image

9. understand that an important advantage of digital signals over analogue signals is that if the

original signal has been affected by noise it can be recovered more easily and explain why

10. recall that the amount of information needed to store an image or sound is measured in bytes

(B)

11. understand that, generally, the more information stored the higher the quality of the sound or

image

12. understand that an advantage of using digital signals is that the information can be stored and

processed by computers.

© OCR 2011 GCSE Science A

P3 Specification

Module P3: Sustainable Energy

P3.1 How much energy do we use?

1. understand that the demand for energy is continually increasing and that this raises issues

about the availability of energy sources and the environmental effects of using these sources

2. recall the main primary energy sources that humans use: fossil fuels (oil, gas, coal), nuclear

fuels, biofuels, wind, waves, and radiation from the Sun

3. understand why electricity is called a secondary energy source

4. understand that power stations which burn fossil fuels produce carbon dioxide which

contributes to global warming and climate change

5. understand that when electric current passes through a component (or device), energy is

transferred from the power supply to the component and/or to the environment

6. recall that the power (in watts, W) of an appliance or device is a measure of the amount of

energy it transfers each second, ie the rate at which it transfers energy

7. use the following equation to calculate the amount of energy transferred in a process, in joules

and in kilowatt hours:

energy transferred = power × time

(joules, J)            (watts, W)           (seconds, s)

OR

(kilowatt hours, kWh) (kilowatts, kW) (hours, h)

8. use the following equation to calculate the rate at which an electrical device transfers energy:

power = voltage × current

(watts, W) (volts, V) (amperes, A)

9. understand that a joule is a very small amount of energy, so a domestic electricity meter

measures the energy transfer in kilowatt hours

10. calculate the cost of energy supplied by electricity given the power, the time and the cost per

kilowatt hour

11. interpret and process data on energy use, presented in a variety of ways

12. interpret and construct Sankey diagrams to show understanding that energy is conserved

13. use the following equation in the context of electrical appliances and power stations:

efficiency =  energy usually transferred                 × 100%

total energy supplied

Candidates will be expected to consider / calculate efficiency as a decimal ratio and as a

percentage

14. suggest examples of ways to reduce energy usage in personal and national contexts.

P3.2 How can electricity be generated?

1. understand that electricity is convenient because it is easily transmitted over distances and can

be used in many ways

2. recall that mains electricity is produced by generators

3. understand that generators produce a voltage across a coil of wire by spinning a magnet near

it

4. understand that the bigger the current supplied by a generator, the more primary fuel it uses

every second

5. understand that in many power stations a primary energy source is used to heat water; the

steam produced drives a turbine which is coupled to an electrical generator

6. label a block diagram showing the basic components and structures of hydroelectric, nuclear

and other thermal power stations

7. understand that nuclear power stations produce radioactive waste

8. understand that radioactive waste emits ionising radiation

9. understand that with increased exposure to ionising radiation, damage to living cells increases

eventually leading to cancer or cell death

10. understand the distinction between contamination and irradiation by a radioactive material, and

explain why contamination by a radioactive material is more dangerous than a short period of

irradiation from the radioactive material

11. understand that many renewable sources of energy drive the turbine directly eg hydroelectric,

wave and wind

12. interpret a Sankey diagram for electricity generation and distribution that includes information

on the efficiency of energy transfers

13. recall that the mains supply voltage to our homes is 230 volts

14. understand that electricity is distributed through the National Grid at high voltages to reduce

energy losses.

P3.3 Which energy sources should we choose?

1. discuss both qualitatively and quantitatively (based on given data where appropriate), the

effectiveness of different choices in reducing energy demands in:

a. domestic contexts

b. work place contexts

c. national contexts

2. understand that the choice of energy source for a given situation depends upon a number of

factors including:

a. environmental impact

b. economics

c. waste produced

d. carbon dioxide emissions

3. describe advantages and disadvantages of different energy sources, including

non-renewable energy sources such as:

a. fossil fuels

b. nuclear

and renewable energy sources such as:

c. biofuel

d. solar

e. wind

f. water (waves, tides, hydroelectricity)

g. geothermal

4. interpret and evaluate information about different energy sources for generating electricity,

considering:

a. efficiency

b. economic costs

c. environmental impact

d. power output and lifetime.

5. understand that to ensure a security of electricity supply nationally, we need a mix of

energy sources.

© OCR 2011 GCSE Science A

C3 Specification

Module C3: Chemicals in our lives – risks and benefits

C3.1 What were the origins of minerals in Britain that contribute to our economic wealth?

1. understand that geologists explain most of the past history of the surface of the Earth in terms

of processes than can be observed today

2. understand that movements of tectonic plates mean that the parts of ancient continents that

now make up Britain have moved over the surface of the Earth

3. understand how geologists use magnetic clues in rocks to track the very slow movement of

the continents over the surface of the Earth

4. understand that the movements of continents means that different rocks in Britain formed in

different climates

5. understand how processes such as mountain building, erosion, sedimentation, dissolving and

evaporation have led to the formation of valuable resources found in England including coal,

limestone and salt

6. understand how geologists study sedimentary rocks to find evidence of the conditions under

which they were formed, to include:

a. fossils

b. shapes of water borne grains compared to air blown grains

c. presence of shell fragments

d. ripples from sea or river bottom

7. understand that chemical industries grow up where resources are available locally, eg salt,

limestone and coal in north west England.

C3.2 Where does salt come from and why is it so important?

1. understand the importance of salt (sodium chloride) for the food industry, as a source of

chemicals and to treat roads in winter

2. recall that salt can be obtained from the sea or from underground salt deposits

3. understand how underground salt can be obtained by mining, or by solution in water

4. understand why the method used to obtain salt may depend on how the salt is to be used

5. understand how the methods of obtaining salt can have an impact on the environment

6. understand the advantages of adding salt to food as flavouring and as a preservative

7. recall the health implications of eating too much salt

8. be able to evaluate data related to the content of salt in food and health

9. recall that Government departments, such as the Department of Health and the Department

for Environment, Food and Rural Affairs, have a role in:

a. carrying out risk assessments in relation to chemicals in food

b. advising the public in relation to the effect of food on health.

C3.3 Why do we need chemicals such as alkalis and chlorine and how do we make them?

1. recall that, even before industrialisation, alkalis were needed to neutralise acid soils, make

chemicals that bind natural dyes to cloth, convert fats and oils into soap and to manufacture

glass

2. recall that traditional sources of alkali included burnt wood or stale urine

3. understand that alkalis neutralise acids to make salts

4. recall that soluble hydroxides and carbonates are alkalis

5. predict the products of the reactions of soluble hydroxides and carbonates with acids

6. understand that increased industrialisation led to a shortage of alkali in the nineteenth century

7. understand that the first process for manufacturing alkali from salt and limestone using coal

as a fuel caused pollution by releasing large volumes of an acid gas (hydrogen chloride) and

creating great heaps of waste that slowly released a toxic and foul smelling gas (hydrogen

sulfide)

8. understand that pollution problems can sometimes be solved by turning wastes into useful

chemicals

9. understand that oxidation can convert hydrogen chloride to chlorine, and that the properties of

a compound are completely different from the elements from which it is made

10. recall that chlorine is used to kill microorganisms in domestic water supplies and as a bleach

11. understand how the introduction of chlorination to treat drinking water made a major

contribution to public health

12. interpret data about the effects of polluted water on health and the impact of water treatment

with chlorine to control disease

13. understand that there may be disadvantages of chlorinating drinking water, including possible

health problems from traces of chemicals formed by reaction of chlorine with organic materials

in the water

14. understand that an electric current can be used to bring about chemical change and make

new chemicals through a process called electrolysis

15. recall that chlorine is now obtained by the electrolysis of salt solution (brine)

Technical details and the ionic reactions are not required

16. recall examples of important uses by industry of the sodium hydroxide, chlorine and hydrogen

produced by electrolysis of brine

17. interpret data about the environmental impact of the large scale electrolysis of brine.

C3.4 What can we do to make our use of chemicals safe and sustainable?

1. understand that there is a large number of industrial chemicals with many widespread uses,

including consumer products, for which there is inadequate data to judge whether they are

likely to present a risk to the environment and/or human health

2. understand that some toxic chemicals cause problems because they persist in the

environment, can be carried over large distances, and may accumulate in food and human

tissues

3. recall that PVC is a polymer that contains chlorine as well as carbon and hydrogen

4. understand that the plasticizers used to modify the properties of PVC can leach out from the

plastic into the surroundings where they may have harmful effects

5. understand that a Life Cycle Assessment (LCA) involves consideration of the use of resources

including water, the energy input or output, and the environmental impact, of each of these

stages:

a. making the material from natural raw materials

b. making the product from the material

c. using the product

d. disposing of the product

6. when given appropriate information from a Life Cycle Assessment (LCA), compare and

evaluate the use of different materials for the same purpose.

© OCR 2011 GCSE Science A

C2 Specification

Module C2: Material choices

C2.1 How do we measure the properties of materials and why are the results useful?

1. interpret information about how solid materials can differ with respect to properties such as

melting point, strength (in tension or compression), stiffness, hardness and density

2. relate properties to the uses of materials such as plastics, rubbers and fibres

3. relate the effectiveness and durability of a product to the materials used to make it

4. interpret information about the properties of materials such as plastics, rubbers and fibres to

assess the suitability of these materials for particular purposes.

C2.2 Why is crude oil important as a source of new materials such as plastics and fibres?

1. recall that the materials we use are chemicals or mixtures of chemicals, and include metals,

ceramics and polymers

2. recall that materials can be obtained or made from living things, and give examples such as

cotton, paper, silk and wool

3. recall that there are synthetic materials that are alternatives to materials from living things

4. recall that raw materials from the Earth’s crust can be used to make synthetic materials

5. interpret representations of rearrangements of atoms during a chemical reaction

6. understand that in a chemical reaction the numbers of atoms of each element must be the

same in the products as in the reactants

7. recall that crude oil consists mainly of hydrocarbons, which are chain molecules of varying

lengths made from carbon and hydrogen atoms only

8. recall that only a small percentage of crude oil is used for chemical synthesis and that most is

used as fuels

9. understand that the petrochemical industry refines crude oil by fractional distillation;

hydrocarbons are separated into fractions of different boiling points, to produce fuels,

lubricants and the raw materials for chemical synthesis

10. relate the size of the forces between hydrocarbon molecules to the size of the molecules

11. relate the strength of the forces between hydrocarbon molecules in crude oil to the amount

of energy needed for them to break out of a liquid and form a gas, and to the temperature at

which the liquid boils

12. understand that some small molecules called monomers can join together to make very long

molecules called polymers, and that the process is called polymerisation

13. recall two examples of materials that, because of their superior properties, have replaced

materials used in the past.

C2.3 Why does it help to know about the molecular structure of materials such as plastics and fibres?

1. understand that it is possible to produce a wide range of different polymers with properties that

make them each suited to a particular use

2. understand how the properties of polymers depend on how their molecules are arranged and

held together

3. relate the strength of the forces between the molecules in a polymer to the amount of energy

needed to separate them from each other, and therefore to the strength, stiffness, hardness

and melting point of the solid

4. understand how modifications in polymers produce changes to their properties (see C2.1), to

include modifications such as:

a. increased chain length

b. cross-linking

c. the use of plasticizers

d. increased crystallinity.

C2.4 What is nanotechnology and why is it important?

1. recall that nanotechnology involves structures that are about the same size as some

molecules

2. understand that nanotechnology is the use and control of structures that are very small (1 to

100 nanometres in size)

3. understand that nanoparticles can occur naturally (for example in seaspray), by accident (for

example as the smallest particulates from combustion of fuels), and by design

4. understand that nanoparticles of a material show different properties compared to larger

particles of the same material, and that one of the reasons for this is the much larger surface

area of the nanoparticles compared to their volume

5. understand that nanoparticles can be used to modify the properties of materials, and give

examples including:

a. the use of silver nanoparticles to give fibres antibacterial properties

b. adding nanoparticles to plastics for sports equipment to make them stronger

6. understand that some nanoparticles may have harmful effects on health, and that there is

concern that products with nanoparticles are being introduced before these effects have been

fully investigated.

© OCR 2011 GCSE Science A

C1 Specification

Module C2: Air Quality

C1.1 Which chemicals make up air, and which ones are pollutants? How do I make sense of data about air pollution?

1. recall that the atmosphere (air) that surrounds the Earth is made up mainly of nitrogen, oxygen

and argon, plus small amounts of water vapour, carbon dioxide and other gases

2. understand that air is a mixture of different gases consisting of small molecules with large

spaces between them

3. recall that the relative proportions of the main gases in the atmosphere are approximately 78%

nitrogen, 21% oxygen and 1% argon

4. understand that other gases or particulates may be released into the atmosphere by human

activity or by natural processes (eg volcanoes), and that these can affect air quality

5. understand how the Earth’s early atmosphere was probably formed by volcanic activity and

consisted mainly of carbon dioxide and water vapour

6. understand that water vapour condensed to form the oceans when the Earth cooled

7. explain how the evolution of photosynthesising organisms added oxygen to, and removed

carbon dioxide from, the atmosphere

8. explain how carbon dioxide was removed from the atmosphere by dissolving in the oceans

and then forming sedimentary rocks, and by the formation of fossil fuels

9. understand how human activity has changed the composition of the atmosphere by adding:

a. small amounts of carbon monoxide, nitrogen oxides and sulfur dioxide to the

atmosphere

b. extra carbon dioxide and small particles of solids (eg carbon) to the atmosphere

10. understand that some of these substances, called pollutants, are directly harmful to humans

(eg carbon monoxide reduces the amount of oxygen that blood can carry), and that some are

harmful to the environment and so cause harm to humans indirectly (eg sulfur dioxide causes

acid rain).

C1.2 What chemical reactions produce air pollutants? What happens to these pollutants in the atmosphere?

1. recall that coal is mainly carbon

2. recall that petrol, diesel fuel and fuel oil are mainly compounds of hydrogen and carbon

(hydrocarbons)

3. understand that, when fuels burn, atoms of carbon and/or hydrogen from the fuel combine

with atoms of oxygen from the air to produce carbon dioxide and/or water (hydrogen oxide)

4. understand that a substance chemically combining with oxygen is an example of oxidation,

that loss of oxygen is an example of reduction, and that combustion reactions therefore

involve oxidation

5. understand that fuels burn more rapidly in pure oxygen than in air

6. recall that oxygen can be obtained from the atmosphere and can be used to support

combustion (eg in oxy-fuel welding torches)

7. understand that in a chemical reaction the properties of the reactants and products are

different

8. understand that atoms are rearranged during a chemical reaction

9. interpret representations of the rearrangement of atoms during a chemical reaction

10. understand that during the course of a chemical reaction the numbers of atoms of each

element must be the same in the products as in the reactants, thus conserving mass

11. understand how sulfur dioxide is produced if the fuel that is burned contains any sulfur

12. understand how burning fossil fuels in power stations and for transport pollutes the

atmosphere with:

a. carbon dioxide and sulfur dioxide

b. carbon monoxide and particulate carbon (from incomplete burning)

c. nitrogen oxides (from the reaction between atmospheric nitrogen and oxygen at the high

temperatures inside engines)

13. relate the formulae for carbon dioxide CO2, carbon monoxide CO, sulfur dioxide SO2,

nitrogen monoxide NO, nitrogen dioxide NO2 and water H2O to visual representations of their

molecules

14. recall that nitrogen monoxide NO is formed during the combustion of fuels in air, and

is subsequently oxidised to nitrogen dioxide NO2 (NO and NO2 are jointly referred to as

‘NOx’)

15. understand that atmospheric pollutants cannot just disappear, they have to go somewhere:

a. particulate carbon is deposited on surfaces, making them dirty

b. sulfur dioxide and nitrogen dioxide react with water and oxygen to produce acid rain

which is harmful to the environment

c. carbon dioxide is used by plants in photosynthesis

d. carbon dioxide dissolves in rain water and in sea water.

C1.3 What choices can we make personally, locally, nationally or globally to improve air

quality?

1. understand how atmospheric pollution caused by power stations that burn fossil fuels can be

reduced by:

a. using less electricity

b. removing sulfur from natural gas and fuel oil

c. removing sulfur dioxide and particulates from the flue gases emitted by coal-burning

power stations

2. understand how the acid gas sulfur dioxide is removed from flue gases by wet

scrubbing:

a. using an alkaline slurry eg a spray of calcium oxide and water

b. using sea water

Candidates are not required to write word or symbol equations

3. understand that the only way of producing less carbon dioxide is to burn less fossil fuels

4. understand how atmospheric pollution caused by exhaust emissions from motor vehicles can

be reduced by:

a. burning less fuel, for example by having more efficient engines

b. using low sulfur fuels

c. using catalytic converters (in which nitrogen monoxide is reduced to nitrogen by loss of

oxygen, and carbon monoxide is oxidised to carbon dioxide by gain of oxygen)

d. adjusting the balance between public and private transport

e. having legal limits to exhaust emissions (which are enforced by the use of MOT tests)

5. understand the benefits and problems of using alternatives to fossil fuels for motor

vehicles, limited to biofuels and electricity.

© OCR 2011 GCSE Science A

B3 Specification

Module B3: Life on Earth

B3.1 Systems in balance – how do different species depend on each other?

1. understand that a species is a group of organisms that can breed together to produce fertile

offspring

2. understand that adaptation of living organisms to their environment increases the species’

chance of survival by making it more likely that individuals will survive to reproduce

3. recall, and recognise when given relevant data, examples of how different organisms are

adapted to their environment, and explain how the adaptations increase the organism’s

chance of surviving to successfully reproduce

4. understand that living organisms are dependent on the environment and other species for

their survival

5. understand that there is competition for resources between different species of animals or

plants in the same habitat

6. relate changes affecting one species in a food web to the impact on other species that are part

of the same food web

7. explain the interdependence of living organisms by using food webs

8. understand that a change in the environment may cause a species to become extinct, for

example, if:

 a. the environmental conditions change beyond its ability to adapt

 b. a new species that is a competitor, predator or disease organism of that species is

introduced

 c. another species (animal, plant or microorganism) in its food web becomes extinct

9. understand that nearly all organisms are ultimately dependent on energy from the Sun

10. recall that plants absorb a small percentage of the Sun’s energy for the process of

photosynthesis

11. recall that this absorbed energy is stored in the chemicals which make up the plants’ cells

12. understand that energy is transferred between organisms in an ecosystem:

 a. when organisms are eaten

 b. when dead organisms and waste materials are fed on by decay organisms

(decomposers and detritivores)

13. explain how energy passes out of a food chain at each stage via heat, waste products and

uneaten parts, limiting the length of food chains

14. calculate from given data the percentage efficiency of energy transfer at different stages of a

food chain

15. understand how carbon is recycled through the environment to include the processes of

combustion, respiration, photosynthesis and decomposition

16. understand the importance of the role of microorganisms in the carbon cycle

17. understand how nitrogen is recycled through the environment in the processes of:

 a. nitrogen  fixation to form nitrogen compounds including nitrates

 b. conversion of nitrogen compounds to protein in plants and animals

 c. transfer of nitrogen compounds through food chains

 d. excretion, death and decay of plants and animals resulting in release of nitrates into the

soil

 e. uptake of nitrates by plants

 f. denitrification

  Foundation tier candidates are not expected to recall details of conversion of

atmospheric nitrogen to nitrates, or nitrates to atmospheric nitrogen

18. understand the importance of the role of microorganisms in the nitrogen cycle, including

decomposition, nitrogen  fixation and denitrification

19. interpret simple diagrams of the carbon cycle and nitrogen cycle

  Foundation tier candidates are not expected to recall nitrogen  fixation or denitrification

20. understand how environmental change can be measured using non-living indicators, including

nitrate levels, temperature and carbon dioxide levels

21. understand how climate and environmental change can be measured using living indicators,

including phytoplankton, lichens and aquatic river organisms such as may y nymphs

22. interpret data obtained from living and non-living indicators to investigate environmental

change.

B3.2 How has life on Earth evolved?

1. recall that life on Earth began approximately 3500 million years ago

2. understand that life on Earth (including species that are now extinct) evolved from very simple

living things

3. understand that there is variation between individuals of the same species and that some of

this variation is genetic so can be passed on to offspring

4. understand that genetic variation is the result of changes that occur in genes (mutations)

5. understand that mutated genes in sex cells can be passed on to offspring and may

occasionally produce new characteristics

6. understand the process of natural selection in terms of the effects of genetic variation and

competition on survival and reproduction, leading to an increase in the number of individuals

displaying beneficial characteristics in later generations

7. describe the similarities and differences between natural selection and selective breeding

8. interpret data on changes in a species in terms of natural selection

9. understand how the combined effect of mutations, environmental changes, natural selection

and isolation can produce new species in the process of evolution

10. understand that evidence for evolution is provided by the fossil record and from analysis of

similarities and differences in the DNA of organisms

11. understand that Darwin’s theory of evolution by natural selection was the result of many

observations and creative thought and why it is a better scientific explanation than Lamarck’s

(eg.  ts with advances in understanding of genetics, no evidence or mechanism for

inheritance of acquired characteristics).

B3.3 What is the importance of biodiversity?

1. understand that organisms are classified into groups according to similarities and differences

in characteristics including:

 a. physical features (eg  flowers in  flowering plants and the skeleton in vertebrates)

 b. DNA

  Candidates will not be expected to give examples of characteristics of particular

taxonomic groups

2. understand that organisms are classified at different levels, and that these levels can be

arranged in an order progressing from large groups containing many organisms with a

small number of characteristics in common (eg kingdom) to smaller groups containing fewer

organisms with more characteristics in common (eg species)

  Candidates will not be expected to recall the names of taxa other than kingdom and

species

3. understand that the classification of living and fossil organisms can help to:

 a. make sense of the enormous diversity of organisms on Earth

 b. show the evolutionary relationships between organisms

4. understand that biodiversity refers to the variety of life on Earth including:

 a. the number of different species

 b. the range of different types of organisms, eg plants, animals and microorganisms

 c. the genetic variation within species

5. understand why biodiversity is important for the future development of food crops and

medicines

6. understand that the rate of extinction of species is increasing and why this is likely to be due to

human activity

7. understand that maintaining biodiversity to ensure the conservation of different species is one

of the keys to sustainability

8. understand that sustainability means meeting the needs of people today without damaging the

Earth for future generations

9. understand that large-scale monoculture crop production is not sustainable because it does

not maintain biodiversity

10. describe and explain how sustainability can be improved, for example in the use of packaging

materials, by considering the materials used, energy used and pollution created

11. understand why it is preferable to decrease the use of some materials, including packaging

materials, even when they are biodegradable, because of:

 a. use of energy in their production and transport

 b. slow decomposition in oxygen deficient land fill sites.

© OCR 2012 GCSE Additional Science