Eli5 Why do wet teabags spin?



Eli5 Why do wet teabags spin?

In: Other

Wet teabags don’t. Weighted wet strings do!

The teabags you’re talking about are the ones that hang from a string. The string is a certain length, and is made up of a bunch of threads twisted together. (These threads are made from smaller fibres twisted together, and so on.) When the string gets wetted, it expands. This makes it more flexible. The weight of the (not wet) teabag pulls it down, trying to straighten it out, which causes it to unwind.

But, the spinning has momentum, so it ends up spinning past the balance point and actually ends up twisting itself differently, so it’ll then slow down and reverse. Ultimately, it ends up slightly longer than when it started out.