What is an interesting subject?

Hello, I am a 17 year old and live in Belgium where we have to make a paperwork with some practical test results as test during the last year of high school.

I follow Industrial science so I am supposed to choose a subject in one of these catogorys:
- Electricity
- Electrical components
- Chemical things or processes
- Physics

My subject has to do something with math which can be anything really (Calculation fly distances,...).

I have to make it about 30 pages so I hope someone can think of something very original where I can find a lot of information about. Because I can't come up with something.

Some examples which are already taken: I can't choose any of these.
- Communication in space
- Electrical motor
- X-rays
- Drones (from the army) like UAV's and unmanned robots.

I thank all of you who can give me some inspiration.

 

Aerospace technology?
....
Maybe some engineering tihngs?