 We're going to look at the effect of pressure on the vapor pressure due to water. Remember a vacuum pump is an instrument that will remove gases. Here you have the O-ring that's going to make a seal. We have water with a thermometer. We're going to make a closed system. And when we turn the vacuum pump on what's going to happen, it's going to take gas molecules out of the container through this tube right here. I'd like you to observe what happens to the liquid and also what happens to the temperature when we change the pressure in the container. So you should see that water boils and it's still only about 70 degrees Fahrenheit.