Hi Paige,
Welcome to the forums!
Your original experiment suggests investigating the impact of changing the orientation of one of your magnets. If you wanted to investigate a different variable that was controlled in the original, you could look at something like the impact of multiple magnets (but imo this wouldn't be as easy to show off your qce syllabus knowledge). You could also look at alternate ways of measuring magnetic field strength for use in your investigation or even compare different methods of measuring magnetic field strength as your investigation (phone app, inducing current, force on scale, etc.)
I would also encourage you to think about anything you noticed could be improved about your original - e.g. if you were only having small variation in your readings, then it's harder to tell your results from the uncertainty. If you did a full write up on the original experiment you should already have listed some of these limitations and how they could be addressed.
My main advice here is:
- pick something where you can readily talk about results using the physics syllabus
- KEEP IT SIMPLE. Like, really simple
- work with others in your class on planning the investigation together (note: after all the data has been collected you need to work individually)
Hope this helps and let me know if you have any more questions