Introduction/Background:

In solids and liquids, molecules are very close together, allowing them to be measurably compressed. But in gases, the molecules are very far apart, allowing them to bounce into each other and the walls of their container, and to be compressed. For example, when the volume of a container of gas is changed, the distance between the walls changes and the amount of time it takes for a particle to get from one wall to another changes. This change results in a different number of collisions per second, and thus causes a different pressure.

This relationship, in which decreased volume results in increased pressure, was discovered in 1661 by Robert Boyle, and is often referred to as Boyle's Law. Adversely, pressure is directly proportional to temperature. This relationship, in which the average kinetic energy of the molecules increases as the temperature of a gas increases, was discovered in 1802 by Joseph Gay-Lussac, and is often referred to as Gay-Lussac's law. The theory of absolute zero was also discovered, in relation to these two laws. The colder something becomes, the slower the molecules move, thus the temperature at which all motion stops, must be the coldest temperature possible (absolute zero). This lab, will study the relationship between pressure and volume at constant temperature (Boyle's Law) and the relationship between pressure and temperature at a constant temperature (Gay-Lussac's Law) through graphing.  

Purpose:

To determine how pressure, temperature, and volume are related in a gas.