Hi, I'm Sean Tvelia, and we're here at Suffolk County Community College to answer the question what happens to the pressure of a gas if we decrease the volume by half. To answer that we have to understand what pressure is. Pressure is the force per unit area and the force is a result of little collisions between atoms and molecules within the vessel along the surface. As we decrease the volume of the vessel with the same number of atoms and molecules, it will increase the number of collisions between those atoms and molecules with the surface and if we increase the number of collisions, we should increase the pressure within the vessel. So to do that we have a system where we can set up and measure the pressure, just basically a syringe and a pressure sensor and all we need to do is decrease the volume in the syringe. Right now it's at 20 milliliters and now I'm going to reduce the volume to 10 milliliters. And by doing that we increase the pressure, we've decreased the volume by half. We should see a corresponding increase in pressure by two. So the original pressure will increase by two.