Some good ideas for science project include does music affect on animal behavior?, Does music have an effect on plant growth?, Which paper towel brand is the strongest?, Can the food we eat affect our heart rate? What plant fertilizer works best? and Does having worms in soil help plants grow faster?. For more, go to http://www.sciencebob.com/sciencefair/ideas.php.
Ehm, I was the Istanbul Science Project winner so, I can help you.(Years years ago) I assume you are between 5th and 7th grade. You have lots of stadiums like baseball stadium, football stadium e.t.c. But they really burn electricity! Sooo what can we do? How about putting some solar cells to the roof! That should work.(This was what i did btw, i put it to a soccer stadium. Of course you have to calculate somethings, and if you can, learn their electricity bills. I learned their bills, believe me, it is not a too hard thing. Do a model of a stadium, put a solar cell to roof, then do the decorations. Of course, when the jury comes, you have to have a good speech.)
I was sitting in my Dr.s office waiting room the other day looking at an aquarium. It had one of those treasure chests at the bottom that filled with air and when the lid could no longer hold back the air pressure it would open and release the air bubbles toward the surface. It appeared that the bubbles all rose to the surface at the same speed regardless of size. I thought, we know the rate at which an object falls to earth, I wondered if anyone has measured the rate at which a bubble rose. I wondered if things like temp and pressure made a difference. What if it wasn't water, say maybe chlorine or ammonia. What if the bubble wasn't air, maybe some other gas. How would what I was observing change, or would it. The aquarium contained a world of questions easy enough to figure out with a little imagination. Just a thought, hope it helps.