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by cool-RR
6337 days ago
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I can think of two wicked experiments right now. I don't know if they're relevant to you, but I'll describe them and you can decide for yourself. 1.
You tie a string from the wall to a motor. Ideally you should be able to control the frequency of the motor, but if you don't have this equipment, it's okay. The string will vibrate rapidly. You then close the lights and put a stroboscope on the string. You tune it, by trial and error, to the same frequency of the motor. Then you see the string frozen in a wave form. You can change the freq slightly to make it move slowly. You can have the kids touch the string at the proper places to make standing waves. 2.
This one is really simple to do. You take a small object (like a soda can) and tie it with a string to the ceiling. (Let's say the string's length is about half the height of the ceiling.) You pull back the can and release it, making it swing from left to right (Without a circular swing.) Then you hand out "half-sunglasses" to the kids. It could just be a piece of dark film, or a partly opaque glass. As long as it's a bit dark and you can see through it. You put the film on one eye, you see the can going in a circle. You put it on the other eye, you see it going in a circle the opposite direction. This happens because the eye with the dark film gets a lower refresh rate. The image on that eye is of the can in a slightly retarded position than the other eye. This messes with the 3D analysis that the brain does, and makes it look like the can is getting closer/farther from you. |
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Your first one is easiest done with a "slinky". You don't need a strobe, because it all happens really, really slowly.
Off-topic: Some people are like slinkies. Of no real use, but they still make you laugh when you see them tumble down stairs ...