2B30.u1 - Glass of Water and Card
Demonstrate how a pressure differential can keep water in an Inverted glass.
Instructions: A glass of water is filled either fully or partially with water and a 3 × 5-inch index card is placed on top. The glass can now be turned over and the card and water will be held in place by atmospheric pressure. The extent to which a card can keep water in an inverted glass depends on the height of the water and the surface created by surface tension between the water and the card.