Year of Invention: 1643
What Is It? A device to measure atmospheric pressure.
Who Invented It? Evangelista Torricelli (in Florence, Italy)
The barometer is an incredibly simple device—no moving parts, no gears, no buttons to push. Still, the barometer allowed scientists to understand atmospheric pressure and the nature of the atmosphere. It made prediction and understanding of the weather available to common people.
The barometer also allowed scientists to discover that there is an upper limit to the atmosphere. This shattered the idea that our atmosphere rises up to the stars and introduced the idea of open space.
No one proposed or considered that the atmosphere had weight and that the atmosphere pushed down on every person and object on Earth. The thought simply had not occurred to anyone. No one studied the air column that rose from Earth’s surface up to the edge of space. It hadn’t occurred to anyone that there was anything there to study.
It had long troubled mining engineers that their hand-driven suction pumps could not lift water more than 33 feet (9.7 meters). In 1620, the problem was turned over to famed scientist Galileo Galilee. Galileo conducted a few experiments but had little success. He conducted the last of these experiments in the mid-1630s at a Florence, Italy, public well assisted by Evangelista Torricelli. Torricelli, the son of a wealthy merchant, was an aspiring scientist.
In this experiment, Galileo looped a tube over a bar raised 40 feet (12 meters) above a public well. One end of the tube reached into the well’s water. The other connected to the suction pump that Torricelli and another volunteer would operate. The two men pumped until sweat dribbled down their faces and their arms ached. But they could not pump water any higher than 9.7 meters above the level of the water in the well.