Scince Fair!!!!!

Hey can you guys give me a good idea for my science fair? Last year I did it on centrepital force. I have been trying to think of something roller coaster related. Does anybody have any ideas!?!?!?!?!?!?!

A model "skycoaster" would be fairly easy to duplicate, and it could demonstrate the concept of momentum. Also, if you have a video of yourself doing tha actual ride and play it along side the model, that would be pretty cool.

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So you want a coaster in your backyard? I hope you have a big backyard.

I have one to. I think I might do it on perpetual motion, (disproving it).