Chapter 13.1, Problem 1BYL

To determine

The definitions of air pressure and the method to measure it.

Answer to Problem 1BYL

A force exerted on an area from all directions is expressed as pressure. Air pressure can be measured using an instrument called a barometer.

Explanation of Solution

The movement of air relative to the surface of the Earth is termed as wind. The differences in air pressure from one place to another and in-between the heights above the surface of the Earth results in its formation. Those kinds of air pressure differences are mainly occurred due to the uneven solar heating, particularly as a function of distance from the equator, or by difference in the temperature between different heights in the atmosphere, or the difference in the way by which land and water respond to the temperature changes. The flow of air occurs from the area of high pressure that is characterized by the sinking of air in the lower pressure, where the rising of air occurs.

Pressure can be defined as a force exerted on an area from all directions. In gas, pressure is associated with the molecular collision frequency that occurred following the collision of a freely moving object or molecules of gas with the other objects.

Air pressure in an area can be measured with the aid of an instrument called barometer. It is a type of sealed glass tube that is fixed in liquid mercury. In response to the air pressure change, the liquid level in the tube rise or fall and thereby allows the measurement of relative pressure.