Beakman explains who made the toilet and then shows a cross-section of a toilet to show the inside. Then he uses colored water to show how gravity pushes the waste out of the toilet into the drain. He then shows how the back tank of the toilet works with valves and gravity to push the water in the toilet bowl down into the drain.
Beakman challenge: drink punch out of a glass with two straws: one inside the glass and the other outside. The straw outside of the glass causes the air pressure inside the mouth to match the outside of the mouth. Now you don't have the ability to get the liquid to move into the mouth due to the air pressure change since it's the same.
Beakman challenge: crush a soda can in a bowl of water without pushing it down with your hands. Beakman heats a little bit of water in the soda can, turns it upside down into the bowl of water and shows how the can crushes. Then he uses a short animation clip to explain how air pressure caused this.