Six-mark questions
Six-mark questions are often the questions that people find the most difficult. In all longer answer questions, but especially the six-mark ones, it is important that you plan your answer and not just rush into it. After all, you would plan an essay or short story before starting. Without a plan it is easy to stray away from the key point and lose marks, get steps in a process in the wrong order or forget key bits of information.
Six-mark questions will start with command words such as 'describe' or 'explain'. The command words 'describe' and 'explain' can be confusing. If you are asked to describe a graph, you will be expected to write about its overall shape, whether it is linear or curved, the slope of gradients etc. If you are asked to explain why a pattern or trend is seen in a graph, you will be expected to use your science knowledge, not just say what you see (which is a description), eg the graph shows the number of radioactive nuclei decreases as time increases. It does this because鈥
Explain how and why questions often have the word 'because' in their answer. Describe questions don't.
The number of marks per question part is given in the form '[6 marks]'. It is essential that you give as many different points in your answer as possible, linking these together. Often, you will be asked to compare two things: make sure that you include both in your answer otherwise, you are likely to limit your score to two marks out of six marks.
Writing six-mark answers with Dr Alex Lathbridge
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How to write six-mark answers in your science GCSE exams.
Sample question 1 - Foundation
Question
The National Grid is supplied with electricity from large-scale electrical generators.
These generators may be driven using different energy sources.
Compare the use of a non-renewable energy source with the use of a renewable energy source to produce electricity for the National Grid. [6 marks]
Edexcel question courtesy of Pearson Education Ltd.
Fossil fuel power stations are cheaper to build than wind farms for the same power output [1]. However, fossil fuel power stations produce CO2 which may increase global warming - renewable energy generators (wind farms) do not [1].
Renewable energy generators have a free or cheaper source of fuel [1].
Fossil fuels have to be taken out of the ground [1].
Nuclear power stations produce radioactive waste, which is dangerous, none of the other energy generators do this [1].
Wind, waves and sun are unreliable sources of energy but fossil and nuclear fuels are always available [1].
First, you should write down the two energy sources you have chosen, and say which is renewable and which is non-renewable, eg "Wind is a renewable energy source. Coal is a non-renewable energy source". Then comment on at least two similarities and two differences between the energy sources.
Sample question 2 - Foundation and Higher
Question
This is a speed-time graph for a car moving on a horizontal road.
Describe the energy transfers taking place during the movement of the car.
You should refer to energy stores as well as transfers between energy stores for all three sections of the graph. [6 marks]
Edexcel question courtesy of Pearson Education Ltd.
Plan the key points which you should include in your answer. Consider each stage of the journey and describe the energy transfers which are taking place. You will need to state where the energy came from and what it is transferred into.
For example:
Fuel is a store of chemical energy [1]. During X, kinetic energy increases as the car's speed increases [1]. The increase in kinetic energy is provided by the chemical energy store [1].
During Y, the kinetic energy stays constant when the car moves at constant speed but energy is still transferred to thermal energy [1].
During Z, kinetic energy decreases and is transferred into thermal energy as the car slows down [1].
During all three sections, work is done against frictional forces in the moving parts of the car and against the drag from the air [1].
Sample question 3 - Foundation and Higher
Question
Describe how the walls of a building affect its rate of cooling and explain ways to reduce the energy transfer. [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.
A thicker wall will mean the building will cool more slowly [1]. A lower thermal conductivity of the material the wall is built from will mean the building will cool more slowly [1] - for example brick has a lower thermal conductivity than metal, so it is better to build walls out of brick [1].
Energy transfer can also be reduced by using thermal insulation - a material with low thermal conductivity [1]. Cavity walls (two walls with a gap between them) will reduce heat transfer [1] as the cavity contains an insulator (air or another suitable insulator) [1].
Plan the key points that you should include in your answer. Describe the features of the wall - thickness and thermal conductivity - and how they link to energy transfer. A way to reduce energy transfer is thermal insulation.