# IB Physics IA Topic Help

#### Emily R.

I'm a junior in high school and currently in the IB Diploma Program. I'm getting ready to start working on my SL Physics Internal Assessment. I was wondering if anyone has any guidance on how complex a topic has to be to score well. I was thinking of testing how the mass, velocity, and position of various objects in a solar system affect their orbit. Is that a complex enough question?

#### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

#### guitarphysics

Hi! In my experience with the IB (and from talking to teachers who've been teaching in the program for years), I've found that to get high marks, you don't necessarily need complex questions/topics. That could even hurt you in some cases.

What I recommend is to analyze a simple physical situation (make sure that it's not simply verifying something like "F=ma"), and write with great detail and precision about it. Important: you should always (or almost always) use data, either through experiments of your own, or from online sources, in your assessments. The IB is highly critical of purely theoretical works. So, for instance, with your proposed question: I think the level of complexity is perfect (for HL IB actually, in SL maybe it's even above the median), but be sure to do two things:
1) make it simple (i.e. theoretically analyze a system with one planet revolving around a sun, and no other planets; be sure to mention that your model was a simplified version of the physical situation in our solar system, for example in that it neglected the small gravitational interactions with other planets, and used Newtonian gravity instead of GR)
and
2) Use data; find an online database with detailed and reliable information about the orbits of the planets in our solar system, and compare the data to your model.

PS. In your original post, you asked how the various physical characteristics of a planet (e.g. mass, position) affects their orbit. This is a bit vague, ambiguous. What exactly do you mean by affects their orbit? The shape of it? Their mean distance from the sun? The time it takes them to go around the sun? Be sure to be precise and focused.

PPS. I'm highly critical of the IB, I think it's no better than the AP system. There's not much freedom here to be original or anything along those lines. Don't try to get too fancy.

PPPS. I got a 7 in HL Physics, but a C on my extended essay which was in physics (predicted grade was an A), so I've acquired some experience; you can trust me on this. Again: don't get too fancy (something I possibly may have done on my extended essay), do stuff that will be easily understood by whoever's correcting your work.

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