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Thermal Physics
 Aim: to verify Charles’ Law and find the Absolute Zero of Temperature See Why a Gas Exerts a Pressure, The Gas Laws Method Set up apparatus similar to that shown in the diagram below. The temperature of the gas can not be measured directly; we assume that the temperature of the gas is the same as the temperature of the water. This is why the experiment takes quite a while, you have to wait a long time for the gas inside the capillary tube to attain the same temperature as the water. The volume of the gas will also not be measured but we will assume that the tube is of uniform cross-sectional area. This means that changes in volume are directly proportional to changes in the length of the air column. Note that this simple arrangement guarantees that the results are measured at constant pressure, an important stipulation of the law being investigated. The pressure of the gas will remain (essentially) the same as the atmospheric pressure throughout the experiment. The concentrated H2SO4 is used for two reasons: 1. you need something to trap the air in the tube (duh... obviously!) 2. it has the effect of drying the air (that is, removing any water vapour). Analysis of results: Plot a graph of length of air column against temperature on the largest scales possible. Draw the best fit straight line and find its slope and the intercept on the volume axis. The equation of this line has the form where a is the slope and b is the intercept on the volume axis. To find a value for the absolute zero of temperature, we simply have to find the value of T which corresponds to zero volume (or zero length of air column). When L = 0, we have

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