Understanding how to approach exam questions helps to boost exam performance. Questions will include multiple choice, descriptions and explanations, using mathematical skills, and extended writing.

You will complete 21 required practical activities if you are studying GCSE Combined Science: Trilogy. You could be asked questions about the apparatus, methods, safety precautions, results, analysis and evaluation of these experiments.

There will be a number of different types of practical based questions. Some will be on the set required practicals, some will cover the working scientifically terms and some will be on other science practicals which you might have done in class. Use all the information given in the question particularly any diagrams to help you understand what the question is about.

*This page contains AQA material which is reproduced by permission of AQA.*

- Question
A student investigated the change in temperature when oils of different specific heat capacities were heated.

This is the method used:

- put 25 g of oil into a boiling tube
- pour 100 ml of water into a beaker and heat it with a Bunsen burner
- when the water is boiling, put the boiling tube into the beaker
- when the temperature of the oil reaches 30 °C, heat for a further 30 seconds and record the rise in temperature
- repeat with different oils
- repeat the whole investigation

**a)**What are the independent and dependent variables in the student’s investigation?**[2 marks]****b)**Give**two**safety precautions the student should have taken.**[2 marks]****a)**- independent - type of oil [1]
- dependent - temperature rise in °C [1]

**b)**Any**two**of the following:- wear safety goggles
- do not heat the oil directly
- do not touch hot equipment

[2]

- Question
A student wants to calculate the density of the two objects shown below:

Describe the methods that the student should use to calculate the densities of the two objects.

**[6 marks]**Measure the length of the cube’s sides using a ruler [1] and use these to calculate volume of the cube [1]. Submerge the statue in water [1] and measure the volume of water displaced [1]. Measure the mass of each object using a balance [1] and calculate the density using: ρ = m ÷ V [1].

You will need to describe both methods and include the density equation. Steps should be logically ordered so that they could be followed by someone else to obtain valid results. You could include the following ideas:

**Metal cube:**- measure the length of the cube’s sides using a ruler
- calculate volume

**Small statue:**- immerse in water
- measure volume/mass of water displaced
- volume of water displaced = volume of small statue

**For both:**- measure mass using a balance
- calculate density using: ρ = m ÷ V