Open response questions
Extended open response questions require longer answers than structured questions that have fewer marks. Open response questions are usually worth 6 marks, but some are worth 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
Open response 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.
Open response 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 full marks, but you do need to write in sentences, linking them logically and clearly.
This page contains AQA material which is reproduced by permission of AQA.
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.
Sample question 1 - Foundation
Question
Poly(ethene) is a polymer made from ethene. Poly(ethene) is used to make plastic bags.
The table is from a life cycle assessment comparing paper bags and plastic bags.
| Paper bag | Plastic bag | |
| Raw material | Wood (renewable) | Oil or gas (non-renewable) |
| Energy used to make in MJ | 1.7 | 1.5 |
| Solid waste produced in g | 50 | 14 |
| Carbon dioxide produced in kg | 0.23 | 0.53 |
| Raw material | |
|---|---|
| Paper bag | Wood (renewable) |
| Plastic bag | Oil or gas (non-renewable) |
| Energy used to make in MJ | |
|---|---|
| Paper bag | 1.7 |
| Plastic bag | 1.5 |
| Solid waste produced in g | |
|---|---|
| Paper bag | 50 |
| Plastic bag | 14 |
| Carbon dioxide produced in kg | |
|---|---|
| Paper bag | 0.23 |
| Plastic bag | 0.53 |
Evaluate which type of bag is more environmentally friendly.
Use data from the table and your own knowledge to support your answer. [6 marks]
Indicative content
A good conclusion as to which bag is more environmentally friendly.
Points that may be used in the argument:
- paper bags are made from a sustainable resource (wood)
- paper bags are more sustainable
- paper bags are biodegradable
- plastic bags are made from a finite resource (oil or gas)
- plastic bags are not sustainable
- paper bags require more energy to manufacture (1.7 MJ compared with 1.5 MJ)
- paper bags produce more waste (50 g compared with 14 g)
- paper bags create less carbon dioxide than plastic bags
- manufacturing of plastic bags has more effect on global warming/climate change/environmental effects
- plastic bags can be recycled
- recycling reduces use of energy sources in manufacture
Sample question 2 - Foundation
Question
A small community of people live in an area in the mountains.
The houses are not connected to the National Grid.
The people plan to buy an electricity generating system that uses either the wind or the flowing water in a nearby river.
Information about the two electricity generation systems is given in the list below:
- the wind turbine costs £50,000 to buy and install
- the hydroelectric generator costs £20,000 to buy and install
- the average power output from the wind turbine is 10 kW
- the hydroelectric generator will produce a constant power output of 8 kW
Compare the advantages and disadvantages of the two methods of generating electricity.
Use your knowledge of energy sources as well as information from the list.
Indicative content
Advantages of both methods:
- both renewable sources of energy
- both have no fuel (cost)
- both have very small running costs
- no carbon dioxide produced
Advantages of wind:
- higher average power output
Advantages of hydroelectric:
- constant / reliable power (output)
- lower (installation) costs
Disadvantages of wind:
- higher (installation cost)
- variable / unreliable power output
- (may) kill birds / bats
Disadvantages of hydroelectric:
- lower power output
- (may) kill fish or (may) damage habitats
- more difficult to set up (within river)
Disadvantages of both methods:
- (may be) noisy
- visual pollution
Sample question 3 - Higher
Question
Read the information about production of copper.
- World demand for copper in 2014 was about 22 million tonnes.
- World reserves of copper are about 700 million tonnes.
- Most of the copper today is obtained from copper ores. The ores are mined.
- Copper ore is heated in a furnace to produce copper sulfide. The furnace is heated by burning fossil fuels. Air is blown through the hot copper sulfide to produce copper and sulfur dioxide.
- Some copper is extracted from low-grade ores by phytomining. Phytomining uses plants to absorb copper compounds. The plants are burned and copper is extracted from the ashes.
A scientist stated:
"More copper should be extracted by phytomining."
Use the information to justify the scientist's statement. [6 marks]
Indicative content
Points that may be used in the argument:
- phytomining conserves supplies of ores
- copper will be available for longer as at present rate of use copper ores will run out in about 35 years
- phytomining conserves supplies of fossil fuels or energy
- less fuel used at a lower cost
- mining scars landscape or produces noise pollution
- mining destroys wildlife habitats
- with more phytomining less need to mine ores
- with phytomining less habitat destroyed or less scarring of landscape
- with phytomining less need to use landfill for waste
- burning fossil fuels produces carbon dioxide/greenhouse gas
- burning fossil fuels causes global warming or climate change
- extraction from ores produces sulfur dioxide which causes acid rain
Sample question 4 - Higher
Question
Carbon nanotubes are cylindrical fullerenes.
Explain the properties of carbon nanotubes.
Answer in terms of structure and bonding. [6 marks]
Indicative content
Properties:
- high tensile strength
- high electrical/thermal conductivity
- high melting point
Explanations:
- nanotubes are fullerenes based on hexagonal rings of carbon atoms, which means that each carbon forms three covalent bonds with three other carbon atoms
- covalent bonds are strong or need a lot of energy to break them
- nanotubes are strong/have high tensile strength and have a high melting point
- the structure means that one electron from each carbon atom is delocalised
- as in metals and graphite, the delocalised electrons can move throughout the structure allowing the carbon nanotube/fullerene to conduct thermal energy and electricity
