How to See Without Glasses [Science Video]

Minute Physics explains why using your fingers to create a small hole can help those with bad vision if they ever come to lose their glasses.

Unlike a lens, a pinhole or small opening can focus light from any distance. Because it’s such a small opening, it only allows light to come through in one place and thus in only one direction from any particular source so there’s no blur and everything is in focus.

[Minute Physics | Via LS]