Verified answer

You will need to narrow down your ideas first to a specific category.

Do you want something related to the environment?

Something interesting related to music (Yes, science can be involved here.)

Or will you prefer something to do with the human body?

In any case, personally I will go for something doable first before tweaking it into something unusual (e.g. Tweaking 'Effects of nicotine on humans' into 'Effects of nicotine on potatoes')

You can have a look here as well if you need more ideas:

http://www.sciencebuddies.org/science-fair-project...

Aerodynamics & Hydrodynamics Astronomy Biotechnology Chemistry Cooking & nutrition technological awareness electrical energy & Electronics Genetics & Genomics song photographs, digital photographs & Video Physics