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 this 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.
Edexcel questions courtesy of Pearson Education Ltd.
Writing six-mark answers with Dr Alex Lathbridge
Listen to the full series on 大象传媒 Sounds.
How to write six-mark answers in your science GCSE exams.
Sample question 1 - Foundation and Higher
Question
Explain the differences between longitudinal and transverse waves. Your explanation should refer to ultraviolet, ultrasound and seismic waves. [6 marks]
Transverse waves have oscillations perpendicular to direction of travel of the wave. Longitudinal waves have oscillations in the same direction as the direction of travel of the wave. Ultraviolet waves and seismic S waves are transverse. Ultrasound and seismic P waves are longitudinal.
Plan the key points that you should include in your answer. Use the definitions you have learnt to explain the differences between longitudinal and transverse waves. State whether each of the types of wave mentioned in the question are transverse or longitudinal.
Sample question 2 - Higher
Question
The figure shows a beam of red light approaching one side of a rectangular glass block. The beam of light will pass through the block and leave through the opposite side.
AB is a wave front.
Discuss the path of the wave front AB as it enters and leaves the glass block. [6 marks]
Point A reaches the glass block before point B. Point A moves into the glass block and slows down as light travels more slowly in glass than in air. Point B is still in air so is travelling faster than point A, this causes part of the wave front to refract. The whole wave front changes direction towards the normal. At the other face, point A exits the block first so the process is reversed. The wave front changes direction again so it is parallel to its original direction.
Plan the key points that you should include in your answer. Consider which side of the beam of light enters the block first, and the effect of the block on the wave as well. Remember to use the key word 'refract' to describe what is happening and indicate whether the wave moves towards or away from the normal. Don鈥檛 forget to discuss what happens as the wave leaves the block too.
It is both sensible and acceptable to annotate and add to the diagram to show what happens to the wave front. Marks can often be allocated if your diagram helps to answer the question.