Meteorologists have been forecasting air pressure for centuries by using barometers. Today, the air pressure is measured by advanced barometer boxes that tell them what's going on with the weather. When air pressure rises, the barometer will forecast clear and dry air. When the pressure starts to fall at a rapid pace, the measurements indicate that a storm is approaching. During hurricanes and tornadoes the pressure will fall to a point that it is known to cause ears to pop in response.
History of Forecasting Air Pressure
The first known instrument in forecasting air pressure was made by Evangelista Torricelli in the 1600s. He hailed from a town in Italy called Faenza. Around 1647 Torricelli, after using suggested advice from Galileo, put mercury into in his vacuum so he could make his barometer.[1]
Supplies for Homemade Barometer
The supplies needed in order to make a barometer from scratch are: a glass, a ruler, some tape, one foot of see through plastic tubing, and a stick of gum.
Steps
- The first step includes standing the ruler inside the glass. Make sure it’s held against the glass so the number side of the ruler can be seen.
- Next, stand the plastic tube against the ruler that’s inside the glass. Don’t let the tube to touch the bottom. Do this by making sure that the tube is a half an inch up on the ruler. Now, fasten the tube to the ruler by taping it.
- After chewing some gum to the point of being soft, fill the glass half way with water. Take the plastic tube and use it as a straw to get the water to where it needs to be on the tube. Finally, use the human tongue to hold the water in the tube and move the gum to the top of the tube so it can form a seal.
- Mark the ruler to take record of where the water level is currently at in the tube. Whenever the water level changes, record the data. High pressure usually means clear skies and low humidity. A low pressure disturbance indicates that moisture is in the air and it may soon rain.
- Notice when the water changes to forecast what’s going on with the air pressure over time.
Scientists and meteorologists use sophisticated technology to forecast air pressure. With a homemade barometer, it’s easy to read the rise and fall of the pressure from home.
1. Bellis, Mary The History of the Barometer. About.com 1997
