Mad About Science: Microscopes

By Brenden Bobby
Reader Columnist

Think about a microscope for a moment. What does your mind’s eye illuminate?

Close-up shot of microscope with metal lens. Courtesy photo.

Are you imagining a doctor in a white lab coat leaning over a high-tech-looking tube surrounded by computers, beakers and slides? Would you believe that the first microscope was developed 700 years ago and has been regularly used by scientific minds ever since? There is even some historical record of the ancient Romans working on a form of microscope 2,000 years ago.

Crude glassmaking was a relatively common practice in Europe around 1200 CE. Artisans even figured out how to grind glass with an abrasive surface to coax light into a focused area to create very crude spectacles and magnifying glasses, likely for monks and scholars that worked to pen copies of the Bible and historical records. Working in an age before electric light was likely hard on the eyes of folks who spent their entire lives as scribes and scholars, so having a little ocular help must have been a necessity.

At some point in the 13th century, someone figured out that they could place a crude lens in a tube and, when aligned properly, could magnify the image that passed through. This was two inventions in one: the telescope and the microscope.

Due to the imprecise nature of early glass grinding, microscopes developed more slowly than telescopes. Three centuries passed before the first intentional microscope was invented by someone who’s hardly known for the microscope, but very famous for his use of telescopes. Galileo Galilei developed the first real microscope in 1609, a device he named occhiolino, which according to various English translations means “wink” or “small eye.” 

Though none of his devices survived to the modern day, a number of diagrams were found of the occhiolino. Based on those renderings, the invention looked almost like the base of a candle sitting on a metal tripod — nothing too fancy, but pretty remarkable for its time. 

Historians suspect the occhiolino could produce around 30x magnification, meaning Galileo wasn’t going to see any cells with his “little eye,” but it helped pave the way for other inventors to improve on the design. It was around this time that eyeglass makers in the Netherlands and Germany began to work on developing microscopes of their own, placing two lenses in opposing ends of the scope to create the first compound microscope, similar to what’s used today.

In 1665, Robert Hooke, at the age of 30, published the illustrated book Micrographia. Using a microscope, an oil lamp and a globe filled with water to create a light condenser, he made a number of observations of the natural world using the microscope and printed them for the world to see. Among these observations: the eye of a fly and a flea, something too small for the average person to see in detail. 

Hooke was also the first person to discover and name a cell while observing cork under a microscope. In case you were wondering why he named it a “cell,” it’s because he believed it looked like a cellula, the Latin word for a small room or compartment, and used to describe spaces ranging from a monk’s chambers to a prostitute’s workplace to a prison cell. I suppose when you discover the basis of all life, you can name it whatever the heck you’d like, even if it’s after the office of the oldest profession in the world.

Though Hooke may have been the first human to discover a cell, the title of “Father of Microbiology” goes to another man, Antonie van Leeuwenhoek — a Dutch scientist and entrepreneur with a wild name and even wilder hair. 

He developed more than 40 different lenses and other additions for microscopes that allowed him to view the world at up to 275x magnification. This allowed him to see larger bacteria and protozoa. Since then, microscope technology has exploded. You can easily purchase a digital microscope with 1,200x magnification for less than $150, and which requires virtually no training or calibration to use.

If you’re reading this article, you know we like to visit extremes, so you may be waiting for me to spill the proverbial beans on the most powerful and extreme microscope ever invented. 

It’s important to know how a regular microscope works before we travel onto the more powerful ones. Photons are light particles. When a photon bounces off something and travels to our eye, our eye transmits that information to our brain, which decodes it and forms an image that we recognize. Photons that travel through microscopes are focused by the lenses, allowing us to see more of a smaller space.

An electron microscope works in a similar way, but it uses electrons instead of photons and electromagnetic coils instead of lenses. Scientists fire a beam of electrons into a vacuum chamber, and that beam is morphed by an electromagnetic field emitted by the coils. This morphed beam passes through the specimen and travels through another magnetic field to magnify the image even further. The electrons hit a fluorescent screen at the bottom of the scope and produce an image that can be as small as the diameter of a single hydrogen atom.

This type of electron microscope is called a transmission electron microscope, or TEM. There are other types of electron microscopes as well, so you should ask a librarian if you’re curious about others.

If you’d like to get an up-close look at the microscopic world, you should stop by Pine Street Woods on Friday, Aug. 26 from 10 a.m.-1 p.m., where I’ll be hanging out with the STEM trailer and the library microscopes — along with sample collectors, glass slides and a community observation board that will allow you to be a citizen scientist for the day. 

See what plants and animals you spot on the trails, or bring back water and soil samples to check under the scopes. If you have a library card, you can even check out a pair of binoculars for your hike — just be sure to bring them back, I’ve only got four sets.

Stay curious, 7B.