Here's why:
* Invented the barometer: Torricelli is credited with inventing the barometer in 1643. This device allowed for the first time to measure air pressure.
* Disproved the "horror vacui" theory: Prior to Torricelli's work, it was believed that nature abhorred a vacuum. His experiments showed that air pressure, not a vacuum, was responsible for holding up liquids in a tube.
* Established the concept of atmospheric pressure: His work laid the foundation for understanding atmospheric pressure and its role in weather patterns, fluid dynamics, and many other areas of science.
While Torricelli was a pioneer, other physicists like Blaise Pascal, Robert Boyle, and Otto von Guericke also made significant contributions to our understanding of air pressure.