More Physics IAs lose marks at the research question stage than at any other point in the process. A vague or untestable question puts a ceiling on your entire Exploration and Analysis score before you’ve even collected data — no matter how well you execute the experiment afterward.
What «Testable» Actually Means
A testable physics research question must contain three explicit elements:
- A single, clearly defined independent variable with a specific numerical range you will use (not «different lengths,» but «string lengths of 20cm, 30cm, 40cm, 50cm, and 60cm»).
- A single, clearly defined dependent variable, with the method of measurement specified (not «the speed,» but «the time for 10 full oscillations, measured with a photogate timer»).
- A physical relationship you are actually investigating — usually derived from a known equation, so you have a theoretical prediction to compare your results against.
Weak vs Strong Research Questions
Weak: «How does the length of a pendulum affect its period?» This has been done in thousands of IAs and offers no personal engagement or original angle.
Stronger: «What is the relationship between the length of a physical (compound) pendulum and its period, and how well does the experimental relationship match the theoretical model for a compound pendulum rather than a simple pendulum?»
This version is testable, has a clear mathematical model to compare against, and shows a more sophisticated understanding than the standard simple-pendulum experiment.
Where to Find a Genuinely Original Topic
The best Physics IA topics usually come from one of three sources:
- A modification of a standard experiment — adding a variable the textbook version ignores (air resistance, non-ideal spring behavior, damping).
- A real-world object or system — analyzing the physics of a sport you play, a musical instrument, or a piece of technology you use.
- A «why doesn’t this match theory» question — starting from a simple experiment, noticing your results deviate from the textbook prediction, and designing a second experiment specifically to investigate why.
Checklist Before You Finalize Your Question
- Can you identify the specific equation or physical law your data will be tested against?
- Can you realistically collect at least 5 data points across a sensible range, with 3+ repeats each?
- Is the equipment available at your school, or can you build/access what’s needed?
- Does the question allow for a meaningful discussion of systematic and random uncertainty?
- Is there room to extend the investigation with a secondary variable if time allows (this boosts Personal Engagement)?
Common Research Question Mistakes
- Choosing a variable that’s genuinely difficult to control (e.g., «temperature» without a way to actually vary and hold it constant)
- Picking a relationship that’s already linear and «obvious,» leaving no room for meaningful data analysis
- Failing to specify units and exact values for the variable range in the question itself
- Choosing a topic purely because it «sounds impressive,» without the equipment to execute it properly
Final Tip
Write your research question, then try to predict — using physics you already know — what shape your graph should take before you collect any data. If you can’t do that, your question isn’t specific enough yet.