How does a magnifying glass work?
A magnifying glass is a convex lens, which means that it is curved outward, much thicker in the middle than around its edges. This shape bends the light waves of objects viewed through it, causing us to see them in unusual ways. When you hold a magnifying glass close to an object, its light waves are widened before they are focused on your eyes, causing the object to appear very large. But when you hold a magnifying glass out and view a distant object with it, the item appears smaller and upside down. This effect is due to the image being beyond the focus of the lens. The more curved a convex lens is, the greater its ability to bend light and magnify. Microscopes (which allow us to look at things that are too small to be seen with our eyes), binoculars, and telescopes (which make far away things look bigger and nearer to us) also use convex lenses.