Syphon Flow
		Materials: Tygon or vinyl tubing Some cups

Procedure: Create a syphon and move flow from one cup to another. Stick a pin in the tube - look for air bubbles entering the fluid.

Explanation: When the bubbles enter the syphon, it is because the pressure in the top bend of the syphon is below atmospheric due to the velocity of the flow, so the air gets sucked in.