Another Extended Essay (EE) Thread!

potatoechippe

Yet another EE thread! I am in IB and want to do my EE paper in physics since it will be relevant to my career. However, I'm having trouble deciding on a topic! Initially I wanted to evaluate the validity of dowsing by setting up a series of experiments that would eliminate human interaction with the dowsing sticks. However my teacher advised me against it, as the last thing I need is an examiner who refuses to mark it, claiming that the theory is not real science and then I don't get my diploma! :(

SO... I came here for more ideas!
Music and environmental are subtopics that interest me most. But of course I'm open to everything!
Here are some other underdeveloped ideas that I had:
-looking at different aspects of a propeller (# blades, angle, material, curve) and seeing how this affects the amount of water displaced for a propeller boat
-different factors affecting the clarity and sound of a guitar (string material, plucking material, plucking location, material of bridge and nut, coil tightness of string ie change over time, body shape and volume)
-factors affecting the energy production of solar panels (angle, smog, wavelength of light, buildup of residue, humidity)

I'm trying to relate physics ideas to specific objects to make a more unique idea. Still having trouble though. If you have any suggestions/can help me build upon what I have, that would be great!