Science fair ideas (1 Viewer)

[Gutter Brain]

Hello all!
I have helped with the science fair at my son's school for a few years. This year our theme is "The Science of Speed". This is for elementary school grades K-5. I have been put in charge of the short skit we do at the end of the night.
Usually we do something exciting for the kids. We try to get the class with the most participating students to come up and help. A few years ago we did the mint Mentos and diet Coke on stage, and let the kids drop in a mint each.
Can you help me come up with some ideas for the skit? I could not think of anything racing related yet.
One idea I had was to demonstrate the speed items fall. Letting the kids drop feathers, light rocks, and a few other items to see what falls fastest. Then, for the finale we could have the someone climb a ladder between the principal and someone else. They could drop a feather over one and a water balloon over the other person. The kids could see the difference in speed and be exciting to see someone hit on the head with a water balloon.
Thanks for any help.

 

[DCM]

Doppler Effect.

Go to Radio shack and get a switch, a buzzer, and a battery to power the buzzer. Stuff these inside a tennis ball. Tether the tennis ball on a string.

Swing the tennis ball in a circle over your head. Everybody in the room will hear the pitch of the buzzer changing, except the guy in the center of the circle.

 

[Gutter Brain]

Thanks, David. That sounds cool.

 

[G'ginna]

Let me talk with Rick to see if it is do-able, but I was thinking about the difference in the way sound travels; speed of light, vs. over copper vs. over the air.