Practicing Circuits - P5

We're going to use the Circuit Builder to have a look at series and parallel circuits: http://phet.colorado.edu/en/simulation/circuit-construction-kit-ac-virtual-lab

Use the simulation to construct a series circuit with 2 batteries and 1 bulb. Look at how fast the electrons move and how bright the bulb is. Use the voltmeter and ammeter to measure voltage and current at different points in the circuit. Add another bulb and see how this changes things. Can you find out a rule for current and voltage in a series circuit? Search the web for what this might be and see if your circuit obeys these rules.

Now try a parallel circuit. See what happens if you make a circuit with one bulb, then add another bulb in parallel. What happens to the brightness of the bulb, and the current and voltage. Why is that? Add a few more bulbs in parallel to see if you can work out the rule for current and voltage in series and parallel.

Follow this Bitesize link to check if you are right: http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_21c/electric_circuits/parallelandseriesrev1.shtml

Practicing Understanding of Circuits

Have a look at this link:

http://www.physicsclassroom.com/class/circuits/U9L3a.cfm

Look at the first 3 parts of the lesson: Journey of a Typical Electron, Resistance and Ohm's Law.
Complete the practice questions to check understanding.

If there are any parts that seem difficult or you don't understand, feel free to email questions. If the same questions keep coming up, I'll post an explanation on the blog.

Remember the address is westfieldacademyscience [at] gmail [dot] com

Revising with Past Paper Questions

The specification for the Biology units years 10 and 11 are studying are on this blog (B5 for year 11, B2 for year 10). Use the links at the side to find the spec for the unit you are currently studying. Have a read through and see where your strengths and weaknesses lie. Use this to decide the areas to revise.

There are many ways of finding past paper questions. One of the simplest is to type into Google: "B5 ocr past paper questions" or something similar.

Alternatively, look at the post from October called "General Revision sites". This has several links to different websites to help guide revision. Have a look around there for some past paper questions and bring what you do into school.

Good luck, and if you have any questions remember to send them to westfieldacademyscience [at] gmail [dot] com

B5 Specification

Module B5: Growth and Development

B5.1  How do organisms develop?

1.    recall that cells in multicellular organisms can be specialised to do particular jobs

2.    recall that groups of specialised cells are called tissues, and groups of tissues form organs

3.    recall that a fertilised egg cell (zygote) divides by mitosis to form an embryo

4.    recall that in a human embryo up to (and including) the eight cell stage, all the cells are  identical (embryonic stem cells) and could produce any type of cell required by the organism

5.    understand that after the eight cell stage, most of the embryo cells become specialised and  form different types of tissue

6.    understand that some cells (adult stem cells) remain unspecialised and can become  specialised at a later stage to become many, but not all, types of cell required by the organism

7.    understand that in plants, only cells within special regions called meristems are mitotically  active

8.    understand that the new cells produced from plant meristems are unspecialised and can develop into any kind of plant cell

9.    understand that unspecialised plant cells can become specialised to form different types of  tissue (including xylem and phloem) within organs (including flowers, leaves, stems and roots)

10.  understand that the presence of meristems (as sources of unspecialised cells) allows the  production of clones of a plant from cuttings, and that this may be done to reproduce a plant  with desirable features

11.  understand that a cut stem from a plant can develop roots and then grow into a complete  plant which is a clone of the parent, and that rooting can be promoted by the presence of plant  hormones (auxins)

12.  understand that the growth and development of plants is also affected by the environment, e.g. phototropism

13.  understand how phototropism increases the plant’s chance of survival

14.  explain phototropism in terms of the effect of light on the distribution of auxin in a shoot tip.

B5.2  How does an organism produce new cells?

1.      recall that cell division by mitosis produces two new cells that are genetically identical to each  other and to the parent cell

2.      describe the main processes of the cell cycle:

         a. cell growth during which:

•            numbers of organelles increase

•            the chromosomes are copied when the two strands of each DNA molecule  separate and new strands form alongside them

         b. mitosis during which:

•            copies of the chromosomes separate

•            the nucleus divides

     i      Candidates are not expected to recall intermediate stages of mitosis

3.      recall that meiosis is a type of cell division that produces gametes

4.      understand why, in meiosis, it is important that the cells produced only contain half the  chromosome number of the parent cell

5.    understand that a zygote contains a set of chromosomes from each parent.

B5.3  How do genes control growth and development within the cell?

1.      recall that DNA has a double helix structure

2.      recall that both strands of the DNA molecule are made up of four different bases which always  pair up in the same way: A with T, and C with G

3.      understand that the order of bases in a gene is the genetic code for the production of a protein

4.      explain how the order of bases in a gene is the code for building up amino acids in the correct order to make a particular protein

i      Candidates are not expected to recall details of nucleotide structure, transcription or translation

5.      recall that the genetic code is in the cell nucleus of animal and plant cells but proteins are produced in the cell cytoplasm

6.      understand that genes do not leave the nucleus but a copy of the gene (messenger RNA) is  produced to carry the genetic code to the cytoplasm

7.      understand that although all body cells in an organism contain the same genes, many genes  in a particular cell are not active (switched off) because the cell only produces the specific  proteins it needs

8.      understand that in specialised cells only the genes needed for the cell can be switched on, but  in embryonic stem cells any gene can be switched on during development to produce any type  of specialised cell

9.      understand that adult stem cells and embryonic stem cells have the potential to produce cells needed to replace damaged tissues

10.  understand that ethical decisions need to be taken when using embryonic stem cells and that  this work is subject to Government regulation

11.       understand that, in carefully controlled conditions of mammalian cloning, it is possible to reactivate (switch on) inactive genes in the nucleus of a body cell to form cells of all tissue types.

(c) 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

Physics Questions

XKCD What If is a brilliant website by a NASA physicist turned cartoonist where he investigates questions sent in by various readers.

There are quite a few about falling objects and various changes in momentum, so they link well to P4 - Explaining Motion. Here are a few examples:
http://what-if.xkcd.com/51/ - What place on Earth would allow you to freefall the longest by jumping off it?

http://what-if.xkcd.com/44/ - How high can a human throw something?

http://what-if.xkcd.com/39/  - How hard would a puck have to be shot to be able to knock the goalie himself backwards into the net?

http://what-if.xkcd.com/28/ - From what height would you need to drop a steak for it to be cooked when it hit the ground?

http://what-if.xkcd.com/18/ - What would it take to stop an out-of-control freight train using only b.b. guns?

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