Have you ever pretended to be a detective? If you’re a fan of great literature, perhaps you’ve even pretended to be one of the greatest detectives of all time. You know…the one who lives at 221b Baker Street in London? Who are we talking about? Sherlock Holmes, of course!

If you want to be just like Sherlock Holmes, you’re going to need a few things. A tweed jacket will come in handy for those damp and breezy back streets of London. You’ll also want one of those cool hats he always wears. Finally, you’ll need an important tool to use when you’re searching for the smallest of clues: a magnifying glass.

Holmes may have used his magnifying glass to search for clues to solve the many mysteries he encountered, but people all over the world use this simple tool for all sorts of tasks every day. With a magnifying glass in hand, you can make the tiniest details seem larger than life. So how do magnifying glasses make the little things larger?

A magnifying glass is actually the simplest form of a basic microscope. It consists of a single convex lens that magnifies an object when the glass is held up to it. Historians believe a scientist named Alhazen created the first magnifying glass in 1021.

Since Alhazen’s time, the principles of optical physics that make magnifying glasses work so well have been the foundation of great advancements in science, particularly biology and astronomy. Today, magnifying glasses can be used for simple tasks, such as making small magazine text easier to read, to complex, scientific tasks, such as studying microscopic organisms.

In addition to simple, handheld magnifying glasses, magnifying lenses play important roles as part of other devices, including binoculars, cameras, microscopes, and telescopes. Without the ability to magnify tiny objects, we wouldn’t know much about tiny things like bacteria and viruses or far-away things, like stars and galaxies.

Magnifying glasses make objects appear larger because their convex lenses (convex means curved outward) refract or bend light rays, so that they converge or come together. In essence, magnifying glasses trick your eyes into seeing something differently than it really is.

When light bounces off an object and travels to your eyes, those light rays travel parallel to each other. When they pass through a magnifying glass, the convex lens bends the parallel rays so that they converge and create a virtual image on your eyes’ retinas.

That virtual image on your retinas appears larger than the real object due to principles of geometry. Despite the magnifying glass, your eyes trace the light rays back in parallel lines to the virtual image. Since the virtual image is farther from your eyes than the object is, the object appears bigger!

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Hearts are a-flutter tomorrow in Wonderopolis. Join us as we celebrate Valentine’s Day by exploring the power of that first glance!