Small Stuff

Some of the most wonderful discoveries in science have been as a result of our being able to see things that are smaller than are possible to see with the naked eye.

When I was studying biology as an undergraduate, I loved looking through a microscope at different kinds of cells. The cells were amazingly intricate and beautiful. Every living thing has these works of art within. It reminds me of a time when one of our teaching fellows was in the lab and said, “Hey, look at this.” He took the carrot stick that he was eating, shaved off a little slice of it, and then projected an image from the microscope he was using to a screen. It was a regular carrot. But the cells were really cool.  

Most microscopes that we are familiar with are light microscopes, or compound light microscopes (compound because they have more than one lens). In a light microscope, the light actually passes through whatever you are looking at (so it has to be really thin), and then gets magnified before the image hits your eye. To see a cell you really have to blow it up. The head of a pin is about one millimeter in diameter, but over 100 human blood cells would fit on that pinhead, lined up end to end. The microscope you used in a high school science class probably magnified things about 400 times. Even the very highest quality light microscopes can only magnify something up to 1000-2000 times. 

Of course, we may want to see things that are even smaller than a conventional microscope can show us. There are higher resolution microscopes called electron microscopes that work by using beams of electrons which can display very tiny subjects — even the structures within a cell. The subjects of electron microscopes have to be placed in a vacuum to be imaged. This means that live cells can’t be placed in an electron microscope. The huge benefit of electron microscopes is that they can magnify items up to 2 million times, providing access to structures that were never possible previously. 

The first compound microscope was invented in the late 1500s when Hans and Zacharias Janssen put a lens on both the top and bottom of a tube. In 1676, Antony van Leeuwenhoek made the discovery that bacteria exist. It was almost 200 years later that Louis Pasteur discovered that bacteria were one of the causes behind many human illnesses. 

Pasteur’s discovery sent medicine off to the races with microscopes. In the late 1800s Walther Fleming discovered cell division, which was the first clue as to how cancer grows. In 2014, the Nobel Prize in Chemistry was won by researchers who developed a new method is using fluorescence to improve the power of microscopic images, so now individual proteins can be observed. Since 2020, there has been a tremendous amount of effort spent attempting to understand the COVID-19 virus, and microscopes were instrumental in developing an effective vaccine. Since 2023, scientists have found that viruses that infect bacteria can make antibiotics more effective, even working on drug-resistant bacteria. We keep making progress, thanks to the amazing microscope.