Trick for seeing without Glasses
Lost your contact lenses? Crushed your glasses? Well you need stare at blurry public transport signs no longer, as simple physics can be exploited to give your vision a small boost using just your hand. Make a tiny hole with your finger (curling up index finger works best) and look through it.You can try it now!! How it works? Your eyes' lenses focus spread out light to create a crisp image on your retina (unless they're damaged, causing you to need glasses), with eye muscles squeezing them so we can focus at different distances. Unlike a lens, a pinhole or other small opening can focus light coming 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. Small holes create crisp images by blocking rather than focusing light though, so the images are much darker.