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.
Describe how a Leslie cube and other equipment could be used to compare how the type of surface affects the amount of infrared radiation emitted.
Suggest any safety precautions
Your answer should include any steps necessary to reduce inaccuracies in the data. [6 marks]
 for any bullet point up to a maximum of six.
An investigation is made into how the mass used to keep a wire under tension affects the wavelength of waves on the wire when oscillated by a vibration generator.
A wooden bridge supporting the wire is moved until two loops (equivalent to one wavelength) is seen after adjusting the masses used.
The experiment is done again to obtain a repeat set of readings.
The diagram illustrates this arrangement:
The frequency of the vibration generator and power supply is 50 Hz.
The table shows the data collected:
|Mass (g)||One Wavelength (cm) - First attempt||One Wavelength (cm) - Repeated attempt|
State with a reason which reading appears to be in error and what should be done to find the speed of waves in the string in each case? [4 marks]
The reading mass = 300 g, wavelength = 28.6 cm is likely to be in error  because it does not follow the pattern of the other readings which show a clear decrease in wavelength as more mass is added .
To find the speed of the waves in each case:
A working solution would either make the image larger or allow the student to see the smaller image more clearly.