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[KIDS] Microscopes: Seeing the Small

Microscope | Readorium

Lenses in Action. Photo By CoolKoon – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=8290039

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.”

Microscope | Readorium

A common light microscope. Photo by Acagastya – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=39763002

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!

Microscope | Readorium

An ant’s head, see through an electron microscope. Image by US Government – http://usgsprobe.cr.usgs.gov/picts.html via en.wikipedia.org, Public Domain, https://commons.wikimedia.org/w/index.php?curid=115204

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.

Microscope | Readorium

The surface of graphite, the stuff pencil lead is made of. Image by Frank Trixler, Ludwig-Maximilians-Universität München (LMU); adapted from LMU/CeNS: Organic Semiconductor Group – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2404543

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!

If you like this article you might enjoy:

The Earth’s Own Force-Field

Blood: That Icky Wonderful Thing Flowing Through You

The Fungus That Turns Ants into Zombies

Where We Got Our Information

The Smithsonian Magazine

http://www.smithsonianmag.com/science-nature/early-microscopes-revealed-new-world-tiny-living-things-180958912/?no-ist

Thermo Fisher Scientific

https://www.fei.com/introduction-to-electron-microscopy/

UMass Medical School

http://umassmed.edu/cemf/whatisem/

University of Iowa

https://cmrf.research.uiowa.edu/transmission-electron-microscopy

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