IA2 Student Experiment: Design, Data and Evaluation
The student experiment is a research task where you design a modified experiment, collect data, and evaluate. The report must show a justified research question, a method controlling variables, processed data with uncertainty, and a reasoned conclusion linked to physics theory.
Concepts to command
- Variables: identify the independent variable you change, the dependent variable you measure, and at least two controlled variables with a reason each.
- Reliability: repeat trials and average; reliability improves with more trials and consistent technique.
- Validity: the experiment measures what it claims; validity depends on controlling variables and suitable apparatus.
- Accuracy: how close results are to the accepted value, affected by systematic error.
- Conclusion: state whether the hypothesis is supported, using the trend and uncertainty, then explain with theory.
Traps to watch
- Listing controlled variables without saying why each matters.
- Confusing reliability (repeatability) with validity (measuring the right thing).
- Reporting a conclusion that ignores uncertainty, e.g. claiming a trend when error bars overlap.
- Suggesting improvements that are vague, such as "be more careful", instead of specific changes.
Worked example
You test whether period of a pendulum depends on amplitude. You vary amplitude and keep length and mass fixed, timing 10 swings and dividing by 10 to reduce reaction-time error. Averaging over repeats improves reliability, and fixed length protects validity. If periods at 10 and 30 degrees differ by less than the timing uncertainty, the conclusion is that amplitude has no measurable effect over that range, consistent with the small-angle approximation.
Rule of thumb
For every improvement, name the specific change and the specific error it reduces. That sentence structure earns evaluation marks.