Robert Hooke

In 1665, English scientist Robert Hooke made an important discovery that helped shape our understanding of biology. While examining a thin slice of cork under a microscope, he noticed that it was made up of many tiny, box-like shapes. These shapes reminded him of the small rooms, or cells, that monks lived in at monasteries. Because of this, he named them “cells,” a term we still use in science today.

Hooke was using one of the earliest compound microscopes, which used more than one lens to magnify objects. The microscope was not very powerful by today’s standards, but it allowed him to see what others could not. Cork is made from the bark of a tree, and Hooke discovered that it was made up of a grid of tiny, empty compartments. He did not realize at the time that what he was seeing were the walls of dead plant cells—the insides had dried up.

Although Hooke didn’t understand the full meaning of his discovery, it started scientists on a path to learning more about the structure of living things. Later scientists like Antonie van Leeuwenhoek, Matthias Schleiden, and Theodor Schwann would expand on his work to form cell theory, the idea that all living things are made of cells.

Robert Hooke’s work showed how important observation is in science. By looking closely at everyday objects, he opened a door to the microscopic world. Today, the word “cell” is used to describe the basic building blocks of all living organisms, thanks to Hooke’s sharp eye and curiosity.

Fun Fact: Robert Hooke’s book Micrographia included detailed drawings of what he saw under the microscope—and it became one of the first bestsellers in scientific history!