Good science fair project idea?

I need a science fair project for school and my mom wont let me use animals so what are some good ideas

Make hover shoes!

Here's where you can learn:

http://www.youtube.com/watch?v=40S8G2ZuRpE

I'm not sure how well it works.

You could go with the good bi carb soda and vinegar volcano..
or you could do flame colours if you were game!
you pretty much need different solutions with metals in them
Copper Sulfate, Zinc Nitrate etc
then you dip a stick into the liquid and put it over a bunsen burner, you can get blues, greens, reds, pinks and oranges
its awesome!

You could always go with the old standby of two plants given different care. One with great soil, great light, plenty of water...and one not. It's usually the lamest one there, but hundreds of kids go with it every single year. And it's easy.

My suggestion is a cloud chamber (CC). Some interesting effects can be observed in what was once called a 'Peanut Butter Jar' Cloud Chamber. A 'CC' creates a fog which will show tracks as ionized particles zip through it.
The reason I thought of a CC is 1.) The Large Hadron Collider is making news as it (slowly) goes online in France/Switzerland; and 2.) I made one myself for 8th grade science fair (many years ago.)

TOMATO: FRUIT OR VEGETABLE? Everybody not in the know, that's a Buffy quote

Hydrogen bubbles.

You bubble hydrogen gas into soapy water. When the bubbles form they have hydrogen in it.

Wet your hand up to the elbows with water. Scoop some bubble into your wet hand and light with fireplace match.

It's more of a demo than a project, but it's cool.