One to two mark questions will start with command words such as ‘describe’ or ‘explain’. Some command words are easy to understand such as:
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 a steep linear increase for the first three hours 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 this form ‘[2 marks]’. It is essential that you give two different answers if a question is worth two marks. Sometimes you can gain a second mark by giving the units in a calculation or stating specific data points, eg 'The speed of the object decreased by 8 m/s.'
This page contains AQA material which is reproduced by permission of AQA.
A teacher demonstrates the penetration of alpha, beta and gamma radiation through different materials. The demonstration is shown in the figure below:
Complete the figure above by writing the name of the correct radiation in each box. [2 marks]
Gamma radiation is the most penetrating and is reduced by thick lead. Beta radiation is fairly penetrating and may be stopped by a few millimetres of aluminium. Alpha radiation is the least penetrating and may be stopped by paper, skin or a few centimetres of air.
Give two safety precautions that should be taken when handling radioactive sources. [2 marks]
Any two from the following:
A teacher wears polythene gloves as a safety precaution when handling radioactive materials.
The polythene gloves do not stop the teacher’s hands from being irradiated.
Explain why the teacher wears polythene gloves. [2 marks]
Wearing gloves prevents transfer of any radioactive material being transferred to the teacher’s hands . If they did get radioactive material on their skin, it could cause damage over a longer period .
Some safety precautions such as gloves, goggles, masks and overalls are designed to stop harmful materials getting into the body through the skin, eyes, nose or mouth.
The electrons in an atom can only orbit at specific distances from the nucleus. State what causes an electron’s distance from the nucleus to increase or decrease. [2 marks]
Increase = absorb electromagnetic radiation 
Decrease = emit electromagnetic radiation