Upside-Down Water Cup

The water stays in the upside-down cup. Ask students to predict what will happen. Cover a full cup with a card, invert it, then release the card. Key idea: Air pressure pushes upward on the card more than the water pushes down. Ask: What is holding the card up? Safety and cleanup: Use plastic cup over tray. https://www.fizzicseducation.com.au/150-science-experiments/force-movement-experiments/upside-down-water-cup/