A describe question covers many possibilities. You could be being asked to recall some facts (e.g. Describe the factors affecting rates of reactions) or a process (e.g. Describe how the body regulates glucose levels in the blood) in an accurate way. Alternatively you could be being asked to state what is shown in a graph (e.g. Describe how the motion of the car changes over the first five minutes). A describe question could be worth anything from 1 to 6 marks so it is always worth looking to see how much you are expected to write.
Whichever type of describe question it is, what is expected of you is a detailed answer given in a logical order.
Have a look at the two answers below and see if you can spot what makes the second one better than the first.
Q. Describe your journey to school.
A1. I walk from my house to the tram stop. Then I get the tram. When I get off, I walk to school.
A2. I leave my house at 7.30 am and walk to Mitcham tram stop. I then take the tram to Merton Park. The tram is usually very busy in the mornings and so I don’t get to sit down. When I get off the tram, I walk down Kingston Road to get to school. Sometimes I stop on the way to buy some crisps. I get to school at about 8.10am.
What makes the second answer better is that it gives the names of places and times. It also adds in detail. These are the same things that could improve your describe answers in science.