Is there a name or more information about this strange common observation?

Asked by Ltryptophan (12091

) November 4th, 2019 from iPhone

Do you know the springs that keep a door from slamming into the wall? They have a rubber cap. Cats and children like to activate them with a boingy twang.

But, I noticed, if you look at the spring, it sort of does something odd visually. I’m not sure just how many back and forths it takes for this shadow effect to occur that seems to leave the springs path from side to side still visible.

It’s interesting. I think the only thing that I can compare it to is how a fan blade essentially disappears while it spins. Maybe there is a relation.

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3 Answers

Reverse rotation effect?

raum (13206

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There is a similar effect, but the effect is not with the spring. The effect is with your eyes, and specifically their inability to keep up with the oscillation of the springs, so the ocular nerve gives up and shades it as gray.

A high speed camera sees every movement of the spring clearly. The human eye isn’t that good.

elbanditoroso (33157

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