Light Bounces Off Objects to Reach Our Eyes

Hey there, I am Atlas, and today we are going to figure out something amazing — how do your eyes actually see anything at all? Light comes from sources like the Sun, a lamp, or a candle. The very first thing to know is that light always travels in a straight line. It cannot curve around corners on its own. If you block it, you get a shadow — proof that light went straight! Now here is the cool part. Most objects do not make their own light. You can only see this book, your desk, or your friend's face because light from somewhere else bounces off them and travels in a straight line right into your eyes. That bouncing is called REFLECTION. Think of it like throwing a rubber ball at a wall. The ball bounces back. Light does the same thing. When light hits a smooth, shiny surface like a mirror, it bounces at a very neat and predictable angle — the angle it leaves equals the angle it arrived. That is why you see a clear copy of your face in a mirror. Rough surfaces, like a wooden desk, scatter light in many different directions at once. That is why you do not see your reflection in a desk — but you can still see the desk itself, because some of that scattered light reaches your eyes. Here is a tricky one: crumpled aluminum foil looks shiny, but its bumpy, bent surface scatters light in many directions just like a rough desk does, so it will not give you a clear reflection either. So every time you see something that does not make its own light — a book, a red apple, your own hand — you are seeing reflected light. For things like the Sun or a lamp, you see their own emitted light directly. But for almost everything else around you: no reflection, no sight!