In Part II, you varied the pressure of the gas inside the test tube by raising and lowering the test tube inside the large beaker and observed the change in the height of the water inside the test tube. Pressure is equal to force per unit area, P = force/area. The pressure of the gas inside the test tube, P_gas is a measure of the amount of force of the gas molecules hitting the area of the walls of the test tube and the surface of the water. When the test tube is positioned in the beaker such that the water height in the test tube is equal to the water height in the beaker, then P_gas is equal to the external pressure, P_atm of the molecules of air in the room hitting the surface of the water in the beaker. Consider the two models below showing the test tube positioned with the open end near the top of the water inside the beaker (Model #1) and with the test tube lowered inside of the beaker (Model #2). 4. What is the relative difference between P_gas and Patm in Model #1? 5. What is the relative difference between P_gas and P_in Model #2?
