when veiwing cars on television the wheels seem to be going backwards this also happens with horse drawn carriges.
2006-11-21 05:00:12 · 4 answers · asked by biker 2 in Cars & Transportation ➔ Other - Cars & Transportation
Basically what you're seeing is a strobe (i.e., stop-action) effect. A movie camera operates at 24 frames per second. If a wheel is turning at some multiple of 24 revolutions per second, the spokes will be in the exact same position every time the shutter opens. Ergo, the wheel will appear to be motionless (though possibly blurred) when the movie is played back. If the wheel now begins to slow down slightly, it doesn't get a chance to rotate all the way around to its original position before the shutter opens again. Therefore it appears to be rotating backward.
Don't get it? Then try the following demonstration, courtesy of Rainbows, Curve Balls & Other Wonders of the Natural World Explained by science writer Ira Flatow. Get a hand eggbeater. While rotating the handle, look at a TV picture through the eggbeater's blades. (For best results, point the eggbeater at the TV and look through the blades the long way.) When you get to 30 revolutions per second, the speed at which a TV picture flashes, the blades will appear to be motionless. Slow down slightly and the blades appear to rotate backward. Fun for the whole family.
Incidentally, this is one of the few times you'll see reverse rotation outside the movies.
2006-11-21 05:03:07 · answer #1 · answered by artisticallyderanged 4 · 7⤊ 0⤋
It's an optical illusion. You'll find it in real life as well, just sit watching cars pass, specifically the wheels.
My husband could give you the details, sadly he is currently in a meeting so I can't ask him to explain it to me (again...I'm not good at retaining what I don't use, but I do appreciate the help. To say nothing of the phenomena!). This means I can't ask him for you. I bet someone comes up with a nifty reason, though. ; )
Edit: Look at ArtisticallyDeranged. He gave you a delightfully lucid explanation AND a link! Too cool by half. LOL
2006-11-21 13:04:58 · answer #2 · answered by tantiemeg 6 · 0⤊ 0⤋
Because they don't synchronise with the speed of the camera, and it gives the impression that there going backwards
2006-11-21 13:09:49 · answer #3 · answered by ? 7 · 0⤊ 0⤋
its an optical illusion, and if you look carefully in real life, thats how it appears too.
2006-11-21 13:17:44 · answer #4 · answered by Miaj 2 · 1⤊ 0⤋