Creating a Barometer

Have you ever seen a weather forecast on TV? If so, you might have noticed the letters "H" and "L" moving around on the weather map. They are often referred to as zones of "high pressure" (H) and "low pressure" (L). The pressure they are talking about is the atmospheric pressure. Changes in air pressure can forecast short-term changes in the weather. But how do you know if the air pressure changes, or if it is high or low? Scientists have developed an instrument called a barometer that can measure atmospheric pressure. In this activity, you will find out how a barometer works by building one yourself!