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…'.

'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.

Edexcel questions courtesy of Pearson Education Ltd.

Sample question 1 - Foundation and Higher


The radiation badge contains a photographic film which is sensitive to radiation.

The radiation badge is sent to a laboratory after a month and the film is checked.

Graphic of a radiation badge and explaining how it works. It contains a photographic film, aluminium, lead and paper.

Explain how the badge shows the amount of different types of radiation that the radiographer has been exposed to. [6 marks]

There might be alpha, beta, gamma radiation as well as X-rays [1]. Where radiation is absorbed by the film, it becomes darker [1]. Different areas of the film are exposed to different types of radiation [1]. This is because alpha particles are likely to be blocked by the paper and so won’t affect the film at all [1]. Beta particles are absorbed by aluminium so will only reach the top part of the film [1]. Gamma rays will be partially blocked by the lead but will affect all of the film [1].

Plan the key points that you should include in your answer. Consider the different types of radiation, and their effect on the film. Then consider why the different types of radiation might not all reach all parts of the film.

Sample question 2 - Foundation and Higher


Some scientists carry out an experiment to measure the radioactivity from a source to be used in a factory.

They measure the background radiation before and after their experiment.

They take the background count at the same place as they do their experiment.

Explain how this procedure helps to make sure that the results of the experiment are valid. [6 marks]

[1] for any of the following points but to get all six marks there must be at least one point from each section.

Need for measurement

Background radiation:

  • is always present/all around us
  • has natural sources exemplified by space, living things, rocks, food, nuclear and medical sources
  • would give false reading in experiment

How and why to measure

Background radiation measurement:

  • is taken at site of experiment because it is different in different places
  • is taken with all apparatus except source in place
  • is taken before and after because it can change with time/they need an average
  • must be worked out for same time as or longer than experiment or rate found so analysis is simpler
  • is taken several times and averaged because it is random


Background radiation measurement:

  • must be subtracted from measurements with source/main count rate