Air Pressure: Question Answers

1)
a. Air pressure is the weight of a colloum of air pushing down on an area or surface.

b. Denser gases have more mass, therefore it exerts a greater air pressure, because it is a larger colloum of air pushing down on a broader area.

2)
a. There are two types of instruments that measure air pressure. The first is a mercury barometer. A mercury barometer is a glass tube with mercury at the bottom. Everything above it is air. As the air pressure changes in the tube, mercury is pushed upward or downward, giving the temperature reading. The second instrument is an Aneroid Barometer. This one has a sensitive metal chamber. With the help of some screws and levers, the metal chamber changes with different air pressures, giving a temperature reading.

b. Weather stations use mercury inches. The National Weather Service maps use millibars. One mercury inch equals 33.87 millibars.

c. 922.2801 millibars.

3)
a. Altitude, or elevation, is the distance the given location is from sea level. As air pressure decreases, altitude increases. And as the pressure decreases, the density decreases.

b. Sea level air has the weight of the entire atmosphere pressing down on it. The higher you go, the less weight is pushed down on you. Density increases because the higher you go, the more spread apart the air molecules are.

c. If you went in a mine shaft with a barometer, the reading would get lower the further down you went. The reason for this is that you have additional pressure the further down you get.