How to Do a CAU Paper for GCSE Science

Three Parts:Hypothesis, source and experimentPaper 1Paper 2

CAU stands for controlled assessed unit in GCSE science. Depending on what the context you've been given, you need to prepare yourself for the questions. These papers are 50 marks and are worth 25% of your science GCSE. In the exam, you are allowed to taken in a planning sheet.

Part 1
Hypothesis, source and experiment

  1. 1
    Understand the purpose of the hypothesis. A hypothesis is a proposal or proposition based on limited evidence that involves an independent variable (what you change on purpose) and the dependent variable (What you will measure). There is also an explanation needed. For example:
    • As the (independent variable) increases/decreases the (dependent variable) increases/decreases. This is because.......................................................
    This example demonstrates the basic structure of the hypothesis.
  2. 2
    Identify the useful source. Depending on the exam board you will always be provided with 3 different sources. In the exam you will be asked to identify which source is useful and which sources is not. The sources will also provide an idea for what experiment you want to do and will often relate to the context. Make sure to write in bullet points on your planning sheet, explaining what is good and what is bad. Include the full name or the book or website
  3. 3
    Come up with an experiment to test out the hypothesis and provide an answer to the context given. Make sure that the method is clear and everything is included. The outline should be:
    • The equipment
    • How you will use it
    • The measurements
    • Fair Test
    • Risk Assessment.

Part 2
Paper 1

  1. 1
    Expect most of the other information to be provided by your teacher. For Paper 1 your planning sheet is essential so make sure that you use it effectively
  2. 2
    Include the hypothesis on the planning sheet. You'll also need to add:
    • The sources that you will be comparing and their full names.
    • The method of the experiment and equipment involved.
    • A risk assessment that includes the hazard, the risk, the level of risk and precaution to take The independent, dependent and control variables and the interval and range; for example, interval: 10cm Range: 10cm to 50cm .
    • You also need to make sure that you include the context.
  3. 3
    Write in full sentences only for the hypothesis and the context. The rest of the planning sheet must be in bullet points.
  4. 4
    Expect the following questions for Paper 1:
    • Question 1: This question will usually be about your hypothesis.
    • Question 2: Will either be to compare your sources or a preliminary experiment. This part is usually 2-4 marks.
    • Question 3: This is the method which is 9 marks. You must use good English and full sentences to gain a full 9 marks and include everything that it asks for.
    • Question 4: This question varies so make sure you know everything that you should and anything the teacher hints. You will also need either a sample table or something related to the investigation, which is worth 2 marks.

Part 3
Paper 2

  1. 1
    Be aware that this is the hardest of the two papers.This is the paper where most people trip up. It is worth 30 marks.
  2. 2
    Understand what Paper 2 consists of. It looks at your own results and a data sheet which has 4 different results in case studies. You will also need to include a sketch graph, which is a rough graph.
  3. 3
    Include the right elements for this paper. You must include:
    • Units
    • Provide numerical answers
    • Use the information that is given
    • Describe fully - If there are any keywords, make sure that you define them in your answer For example, were there any anomalies in your results? The perfect response: No, there were not any anomalies.
      • Anomalies are results that do not fit the pattern. For example, at --------cm the height was --------------- mm but at ----------------------cm the height was ----------------mm therefore there were no anomalies.
  4. 4
    Prove the units without fail. Always give examples from yours or other's data. Be confident when drawing graphs.
  5. 5
    Pace yourself. Always make sure that you are satisfied with your answer and move on quickly. Try to get the easy questions out of the way first.


  • Practice past papers.


  • Don't over stress yourself.

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