Practical Investigation

The Practical Investigation (AS91521) is a 6-credit internal — the biggest single Level 3 Physics standard. The key word in its title is "test": unlike Level 2's open-ended AS91168, here you start with a stated physics theory predicting how two variables should be related, then design an investigation to test whether your data actually supports it.

That changes what "good" analysis looks like:

• You state the theoretical relationship (and the power $n$ it predicts) before analysing your data, not after.
• Uncertainty is propagated properly through calculations, not just estimated from half a range.
• Your conclusion must explicitly compare the experimental gradient/power against the theoretical prediction and judge, with reasoning, whether the data supports the theory.

Every page below extends the Level 2 investigation method with this extra layer of rigour. Worked examples use common practice contexts — your own investigation will use whatever theory your class is testing.