People really like tiny things. I mean, small puppies, kittens, baby birds and even baby reptiles are cute, right? Many kids enjoy playing with dolls, which are tiny people, and dollhouses, which are tiny houses with tiny furniture. Small cars are often “cooler” than big, clunky ones. Miniature, or very small, art is often very valuable.
Seeing tiny things is very important to science. For example, the germs that cause diseases are usually too small for the human eye to see. If people had not been curious about searching for tiny things, we would never have learned so much about disease! Because the human eye isn’t strong enough, we need to use a device called a “microscope” to look at tiny things like germs.
The idea of using a tool to see better has been around for a while. In the 14th century, Europeans started making lenses to correct people’s eyesight. A lens is simply a piece of glass that can bend light to make an image of an object. In the 16th century, Dutch lens makers began making better and better lenses. Soon, lens makers began putting lenses together to make the first microscope. The word itself was born in 1625, in a book by two Italian scholars. They had been using microscopes to study bees.
Since then, technology has allowed us make even more complex microscopes. Some of them don’t use light at all! Let’s take a look at the basic kinds of microscope.
Light Microscope: Light microscopes are the most common type. They can be simple, with a single lens, or compound. Compound light microscopes use mirrors and lenses to reflect and refract (which mean “change the direction of”) light and make objects look bigger. You’ve probably seen this type of microscope in your school lab. They can make things look up to around 1000 times bigger. We say they “magnify images up to 1000x.”
Electron Microscope: These are advanced microscopes are weird in that they don’t use light at all! Instead of beams of light, their lenses and magnets work with beams of electrons and other particles that carry electric charge. They tend to create colorless images. Electron microscopes can be used to find extremely tiny details, like the insides of bacteria. A modern one can be 4000 more powerful than a light microscope, and 4 million times better than the human eye!
Scanning Probe Microscope: Scanning probe microscopes are even weirder. Instead of using a lens, these microscopes have a very small, very sharp needle called a “probe”. The probe comes very close to objects to measure the atoms on the surface. They can make images of things that are around the size of atoms, on the scale of ten billionth of a meter.
So there you go. Using light, electrons, and even tiny needles that map surfaces, scientists can see parts of the world around them that their ordinary, human eyes would never allow. Yay for microscopes!
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Where We Got Our Information
The Smithsonian Magazine
Thermo Fisher Scientific
UMass Medical School
University of Iowa