1. Presentation on Barometers

2. A Barometer measures air pressure.
An Italian scientist named Torricelli built the first barometer in People still use barometers based on Torricelli's design to measure air pressure.

3. Barometers
Torricelli’s Barometer

4. How is the barometric pressure measured?
Air pressure is also called barometric pressure because barometers are used to measure it. (Related: How a mercury barometer works). The National Weather Service reports surface air pressure in inches of mercury, while air pressure aloft is reported in millibars, also known as hectopa scals (hPa).

5. Why is the barometer so important?
A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure. The atmosphere is the layers of air wrapped around the Earth. That air has a weight and presses against everything it touches as gravity pulls it to Earth. Barometers measure this pressure.