My son has to do a science project for 6th grade. We are thinking about dropping weighted ping pong balls from about a 6 six story height. We would measure how fast each ball fell. (air resistance would cause the lighter balls to fall slower).
No it wouldn't. The air resistance would be the same for a same size ping pong ball no matter what weight difference. Didn't Sir Isaac Newton already demonstrate that weight is not a factor in a falling object?
Any ideas on how we could time the ball drop?
Sure, optical sensors/emitters on the outside of a plastic tube or pipe that has a ID diameter just a little larger then a ping pong ball that is 'looking through' the pipe, using one sensor/emitter at near the top of the tube and one near the bottom of the tube. Arduino would time interval between start and stop, speed is just a math equation based on that elapsed speed.
Lefty