History

• At the time Torricelli lived, people knew some things about air pressure, and they thought that stormy weather was coming when the air pressure changed. However, they had no way to measure air pressure.
  
  

Significance

• Once he built his barometer, Torricelli was able to measure the air pressure and then make predictions about weather changes. People today still use the barometer to predict weather changes.
  
  

Function

• A barometer is an instrument used to measure the pressure of the air or the atmospheric pressure.
  
  

Misconceptions

• Some people think that the barometer reveals what the weather is like outside their windows at that moment. The barometer actually tells what the weather is going to be in a day or two. It predicts the coming weather.
  
  

Benefits

• The barometer is a significant invention. By knowing the atmospheric pressure, we can predict the weather.
  
  

Famous Ties

• It was Torricelli's famous friend Galileo who gave him suggestions for how to built the barometer. Torricelli served as Galileo's assistant and secretary during the last few months of Galileo's life.