A barometer is an instrument that measures atmospheric pressure by balancing the weight of mercury, water, or air in a tube against the outside air pressure. Evangelista Torricelli invented the barometer in 1643 using a vacuum to compare atmospheric pressure to zero pressure. Barometers can help forecast weather by measuring changes in air pressure, with high pressure indicating colder weather and low pressure signaling warmer temperatures and rain.

1. Barometer By: Sabrina and Sydney

2. What is a barometer? An instrument measuring atmospheric pressure (the weight of the air in the atmosphere)

3. What its used for? A barometer is used to help forecast the weather by measuring atmospheric pressure, or air pressure. It measures the change in atmosphere pressure.

4. How it works? It can measure the pressure exerted by the atmosphere using: Water Air Mercury The barometer works by balancing the weight of mercury in the tube against the atmospheric pressure.

5. History of the Barometer In 1643 Evangelista Torricelli invented the barometer. He used a vacuum to compare ever-present atmospheric pressure with zero pressure The word “baros” means weight in Greek and the word “metron” meaning measure. The barometer used the principal of a vaccum to measure the weight of the air.

6. What barometers look like More information: Air pressure, which is what a barometer measures, can determine what kind of weather we are going to suspect. For example; High pressure, you can suspect colder temperatures While low pressure, you can look for warmer weather and rain.

7. Work Sited www.weather.about.com www.wisegeek.com www.barometer.ws Bing.com/images – search barometer www.kids.earth.nasa.gov