• A barometerbarometer image by Peter Baxter from Fotolia.com
  
  A barometer is a scientific instrument that measures atmospheric pressure, which has the ability to tell what short-term changes there will be in the weather. Meteorologists use barometers to determine when high and low pressure systems will come through an area, and if precipitation will accompany them. By participating in barometer activities with your students, you can give them a better idea of how to predict an important facet of their world.
  
  

What's the Weather?

• Create a worksheet for your students with several different word problems that talk about weather. Each problem talks about how the weather was a few hours ago, what it is now and what they expect it to be in the near future. Ask your students about how meteorologists predict the weather, and how they know what it will be based on what they know now.
  
  Discuss weather prediction based on rising or falling atmospheric pressure. Have them split into groups and make an educated guess about what the barometric pressure was before, during and after based on the weather described in each word problem.
  
  

The First Barometer

• This activity works well if you have yet to discuss the barometer or if you have only just gotten into discussions about atmospheric pressure. Hand out a story based on Toricelli's experiments with the weight of air in the 1600s. Explain what happened in the experiment (the mercury in his device rose and fell) but not why it happened (atmospheric pressure). Have your students generate hypotheses as to why the liquid may have risen or fallen.
  
  This activity works well when it leads into the creation of a homemade barometer, so that they can perform Toricelli's experiment themselves. Instead of having a written story about the barometer experiments, you may wish to write a short play to get the students to laugh and focus a bit more.
  
  

Make a Barometer

• This activity will require the students to split into groups of five. Each group will receive a tall glass, four paper clips, a plastic or glass bowl, a pen and water. Have the students place paper clips around the rim of the glass, fill the glass two-thirds full with water, and place the bowl upside down over top of the glass. Next, they should carefully turn the bowl and the glass over so that the bowl is resting on a flat surface. Some water will run out of the glass, but most of it will stay in. Mark the starting place of the water within the glass and have them take the homemade barometer outside. As the water rises, this means that there has been a rise in atmosphere pressure.
  
  

Height of a Building

• Using a mercury barometer, it is possible to determine the height of a tall building. This physics problem involves calculating the pressure of the air at the top of a building and the pressure of the air at the bottom of the building. Have your students attempt to solve the problem using the equation listed on the Ohio University site. Discuss with them why this method might not be ideal for determining the building's height. You can also discuss the famous academic urban legend known as the "Barometer Problem," in which a famous up-and-coming physics student had a disagreement with his professor over this exact question.