Six-mark questions
Six-mark questions are extended open response questions. These require longer answers than the structured questions that have fewer marks. It is wise to plan your answer first by making some notes. This will help you to include all the key points.
To gain full marks, you need to:
- support explanations using scientific knowledge and understanding
- use appropriate scientific words
- write clearly and link ideas in a logical way
- maintain a sustained line of reasoning
Writing six-mark answers with Dr Alex Lathbridge
Listen to the full series on BBC Sounds.
How to write six-mark answers in your science GCSE exams.
Six-mark questions often use these command words:
- Describe means you should recall facts, events or processes accurately. You might need to give an account of what something looked like, or what happened.
- Explain means you need to make something clear, or state the reasons for something happening.
- Compare means you need to describe similarities and differences between things. If you are asked to compare X and Y, write down something about X and something about Y, and give a comparison. Do not just write about X only or Y only.
- Evaluate means you must use information supplied, or your own knowledge, to consider the evidence for and against or to identify strengths and weaknesses. You must then complete your answer with a conclusion, stating which is better and why, for example.
Six-mark questions may be synoptic questions, which bring together ideas from two or more topics. For example, a question about fertilisers could include ideas about covalent substances, acids and alkalis, chemical calculations and effects on the environment.
The answers shown here give marking points as bullet points. You do not usually need to include all of them to gain six marks, but you do need to write in sentences, linking them logically and clearly.
Sample question 1 - Foundation
Question
Ethene is used to make poly(ethene). Poly(ethene) is used to make plastic bags. The table below shows data from a Life-Cycle Assessment (LCA) for a plastic bag and a paper bag.
| Plastic bag | Paper bag | |
| Raw materials | Crude oil or natural gas | Wood |
| Energy used in MJ | 1.5 | 1.7 |
| Mass of solid waste in g | 14 | 50 |
| Mass of CO2 produced in kg | 0.23 | 0.53 |
| Volume of fresh water used in dm3 | 255 | 4520 |
| Raw materials | |
|---|---|
| Plastic bag | Crude oil or natural gas |
| Paper bag | Wood |
| Energy used in MJ | |
|---|---|
| Plastic bag | 1.5 |
| Paper bag | 1.7 |
| Mass of solid waste in g | |
|---|---|
| Plastic bag | 14 |
| Paper bag | 50 |
| Mass of CO2 produced in kg | |
|---|---|
| Plastic bag | 0.23 |
| Paper bag | 0.53 |
| Volume of fresh water used in dm3 | |
|---|---|
| Plastic bag | 255 |
| Paper bag | 4520 |
A company stated: 'A Life-Cycle Assessment shows that using plastic bags has less environmental impact than using paper bags'.
Evaluate this statement. Use your knowledge and the information from the table.
[6 marks]
This question is AQA material which is reproduced by permission of AQA.
The following are vaild points that could be included in your answer. It is important that you do not bullet point your answer but write your sentences in full.
- Paper bags are made from a renewable resource
- Plastic bags are made from a finite resource
- Paper bags require more energy to manufacture
- Paper bags produce more waste
- Paper bags are biodegradable
- Paper bags create more CO2
- CO2 created by paper bags will be offset by photosynthesis in growing wood
- Paper bags require much more fresh water
- Paper bags cannot be recycled
- Agree because non-renewability is less important than other factors
Or…
- Disagree because the other factors are more important than non-renewability
Or…
- Can’t say because the data is inconclusive/incomplete/insufficient
Sample question 2 - Foundation
Question
A student set up six test tubes to investigate the rusting of iron. This is the method used for each test tube.
- Measure the mass of the nail using a balance.
- Leave the nail in the test tube for 6 days.
- Measure the mass of the nail after six days.
The results obtained by the student are shown in the table below.
| Test tube | Mass of nail in g | Mass of nail after 6 days in g |
| 1 | 8.45 | 8.91 |
| 2 | 8.46 | 8.46 |
| 3 | 8.51 | 8.51 |
| 4 | 9.65 | 9.65 |
| 5 | 9.37 | 9.45 |
| 6 | 9.79 | 9.79 |
| Test tube | 1 |
|---|---|
| Mass of nail in g | 8.45 |
| Mass of nail after 6 days in g | 8.91 |
| Test tube | 2 |
|---|---|
| Mass of nail in g | 8.46 |
| Mass of nail after 6 days in g | 8.46 |
| Test tube | 3 |
|---|---|
| Mass of nail in g | 8.51 |
| Mass of nail after 6 days in g | 8.51 |
| Test tube | 4 |
|---|---|
| Mass of nail in g | 9.65 |
| Mass of nail after 6 days in g | 9.65 |
| Test tube | 5 |
|---|---|
| Mass of nail in g | 9.37 |
| Mass of nail after 6 days in g | 9.45 |
| Test tube | 6 |
|---|---|
| Mass of nail in g | 9.79 |
| Mass of nail after 6 days in g | 9.79 |
Use the results of the student's investigation to draw conclusions about the factors affecting the rusting of iron. Include an evaluation of the effectiveness of different coatings at preventing the rusting of iron.
[6 marks]
This question is AQA material which is reproduced by permission of AQA.
The following are vaild points that could be included in your answer. It is important that you do not bullet point your answer but write your sentences in full.
Simple statements:
- nail rusted in test tubes 1 and 5
- test tubes 1 and 4 contained air/oxygen and water
- nail did not rust in test tubes 2, 3 and 4
- test tube 2 no water present
- test tube 3 no air/oxygen present
- test tube 4 paint stopped rusting
- test tube 6 scratched galvanised iron did not rust
- test tube 6 galvanising stopped rusting
Conclusions:
- both water and oxygen are required for rusting
- coatings that prevent water and oxygen reaching the metal prevent rusting
- when paint is scratched, iron comes into contact with water and oxygen and the iron rusts
- in test tube 5, less iron exposed so less rusting than in test tube 1
- galvanising is better at resisting rusting than paint when scratched
- zinc is more reactive than iron, so when galvanised metal is scratched, zinc reacts with water and oxygen first/sacrificially
Evaluation:
- oil and paint are effective at preventing rusting when the coating is intact
- galvanising is the most effective coating because it prevents rusting even when scratched
Sample question 3 - Higher
Question
The table below gives some information about milk bottles.
| Glass milk bottle | Plastic milk bottle | |
| Raw materials | Sand, limestone, salt | Crude oil |
| Bottle material | Soda-lime glass | HD poly(ethene) |
| Initial stage in production of bottle material | Limestone and salt used to produce sodium carbonate | Production of naphtha fraction |
| Maximum temperature in production process | 1600°C | 850°C |
| Number of times bottle can be used for milk | 25 | 1 |
| Size(s) of bottle | 0.5 dm3 | 0.5 dm3, 1 dm3, 2 dm3, 3 dm3 |
| Percentage of recycled material used in new bottles | 50% | 10% |
| Raw materials | |
| Glass milk bottle | Sand, limestone, salt |
| Plastic milk bottle | Crude oil |
| Bottle material | |
| Glass milk bottle | Soda-lime glass |
| Plastic milk bottle | HD poly(ethene) |
| Initial stage in production of bottle material | |
| Glass milk bottle | Limestone and salt used to produce sodium carbonate |
| Plastic milk bottle | Production of naphtha fraction |
| Maximum temperature in production process | |
| Glass milk bottle | 1600°C |
| Plastic milk bottle | 850°C |
| Number of times bottle can be used for milk | |
| Glass milk bottle | 25 |
| Plastic milk bottle | 1 |
| Size(s) of bottle | |
| Glass milk bottle | 0.5 dm3 |
| Plastic milk bottle | 0.5 dm3, 1 dm3, 2 dm3, 3 dm3 |
| Percentage of recycled material used in new bottles | |
| Glass milk bottle | 50% |
| Plastic milk bottle | 10% |
Evaluate the production and use of bottles made from soda-lime glass and those made from HD poly(ethene). Use the information given and your knowledge and understanding to justify your choice of material for milk bottles.
[6 marks]
This question is AQA material which is reproduced by permission of AQA.
The following are vaild points that could be included in your answer. It is important that you do not bullet point your answer but write your sentences in full.
- Glass - 2 stages in production of soda-lime glass
- Glass - second stage, heating sand, limestone and sodium carbonate
- HDPE - 3 stages in production
- HDPE - second stage, cracking of naphtha to obtain ethene
- HDPE - third stage, polymerisation of ethene
- Fewer stages in glass production, may be quicker
- Higher temperature in glass manufacture, therefore may be higher energy requirement
- Glass bottle can be reused
- Consideration of collection/cleaning costs to reuse glass bottles
- Other glass products can be made from recycled glass
- Plastic has greater range of sizes
- Both produced from limited raw materials
- Higher percentage recycled materials in glass conserves raw materials
Sample question 4 - Higher
Question
Different materials are used to make different parts of a high-performance car. The decisions about which material to use are based on the properties of those materials. The table below shows some data about different materials.
| Material | Relative strength | Density in g/cm3 | Other properties |
| Carbon fibre reinforced polymer | 10 | 1.6 | Rigid, can be moulded into any shape |
| Glass ceramic | 2 | 2.5 | Brittle, transparent, poor conductor of heat and electricity |
| aluminium alloy | 7 | 2.7 | Malleable, does not corrode |
| Steel | 8 | 7.6 | Malleable, corrodes slowly |
| Material | Carbon fibre reinforced polymer |
|---|---|
| Relative strength | 10 |
| Density in g/cm3 | 1.6 |
| Other properties | Rigid, can be moulded into any shape |
| Material | Glass ceramic |
|---|---|
| Relative strength | 2 |
| Density in g/cm3 | 2.5 |
| Other properties | Brittle, transparent, poor conductor of heat and electricity |
| Material | aluminium alloy |
|---|---|
| Relative strength | 7 |
| Density in g/cm3 | 2.7 |
| Other properties | Malleable, does not corrode |
| Material | Steel |
|---|---|
| Relative strength | 8 |
| Density in g/cm3 | 7.6 |
| Other properties | Malleable, corrodes slowly |
Use the information in the table, and your own knowledge, to explain why:
- carbon fibre reinforced polymer is used for the body of the car instead of steel
- glass ceramic is used for the windscreen of the car
- aluminium alloy is used for the chassis (framework) of the car instead of steel
- thermosetting polymers are used to strengthen the protective clothing for the driver
[6 marks]
This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.
The following are vaild points that could be included in your answer. It is important that you do not bullet point your answer but write your sentences in full.
- CFRP is used for the body panels because it is very strong to protect the driver...
- ...and lightweight so the car will go faster...
- ...and is rigid once moulded into the most aerodynamic shape for the car.
- Glass is used for the windscreen because it is the only transparent material (in the table) so the driver can see through it.
- Aluminium alloy is used for the chassis because it is nearly as strong as steel but has a much lower density...
- ...therefore the car will be able to go faster.
- Thermosetting polymers are used for the protective clothing because they are durable/strong and will not melt in the event of a fire.
