Lenses

📖 In short

A lens is a clear piece of glass or plastic with at least one curved surface. When light passes through it, it bends, so the lens makes things look bigger or smaller, or gathers light. We find lenses in glasses, cameras, microscopes and telescopes.

🤩 Did you know?

A convex lens makes an upside-down image of faraway things.
The point where the rays meet is called the focus.
Arab scholars of old made lenses from glass and crystal and studied how light bends.
Contact lenses go right on the eye.

🔎 Find out more

🌟 The convex lens

A convex lens is thick in the middle and thin at the edges. It gathers light rays into one point and makes nearby things look bigger, like the magnifying glass we use to read small print.

🔍 The concave lens

A concave lens is thin in the middle and thick at the edges. It spreads light rays apart and makes things look smaller. It's used in glasses for people who can't see far away well.

💡 A lens in your eye

Inside your eye is a natural, flexible lens that focuses light onto the retina so you see clear pictures. When it doesn't work well, glasses help it.

🎯 A safe experiment

Put a drop of water on a clear sheet over a book and it will magnify the letters underneath, because the drop has become a tiny convex lens! But never point a lens at the sun, as it could start a fire or hurt your eyes.