Microscope

The microscope is an instrument that makes very small structures visible by using lenses to magnify an image. The first compound microscopes appeared in Europe around the beginning of the 17th century. They are often associated with Dutch spectacle makers Hans and Zacharias Janssen, although the exact history of the earliest instruments is uncertain. In the 1660s, English scientist Robert Hooke used an improved microscope to examine thin slices of cork.

He observed small compartments and called them “cells” because they reminded him of the rooms in a monastery. A few years later, Dutch scientist Antonie van Leeuwenhoek built powerful single-lens microscopes and observed bacteria, protozoa, sperm cells and other microscopic structures. His observations revealed a previously unknown world of living organisms. Microscopes became increasingly precise as lens-making techniques improved.

Better lenses reduced distortions and allowed scientists to distinguish smaller details. In the 19th century, advances in optics helped establish microscopy as an essential scientific tool, especially in biology and medicine. The light microscope, which uses visible light and glass lenses, can reveal cells and many microorganisms, but its resolution is limited by the wavelength of light.

In the 20th century, electron microscopes made it possible to observe much smaller structures because they use beams of electrons instead of visible light. Other techniques, including fluorescence microscopy, allow researchers to highlight particular structures inside cells. Today, microscopes are used in laboratories, hospitals, universities and industry. They help scientists study cells, tissues, microorganisms and materials, making the invisible world accessible to direct observation.