Magdeburg Suction Discs

They can be very difficult to separate. Ask students to predict what will happen. Press cups together and invite a controlled pull apart. Key idea: Air is squeezed out and outside air pressure pushes the cups together. Ask: What is pushing the cups together? Safety and cleanup: Use handles; no sudden release near faces. https://www.google.com/search?q=%22Magdeburg%20Suction%20Discs%22%20science%20demonstration%20experiment