Rubber Magdeberg Hemispheres or physical science and physics provides a classic demonstration of the force of air pressure. Be amazed at how difficult it is to pull them apart.
An economic version of the classic force of air pressure demonstration. Air is removed by simply pushing the two rubber plungers together. Once they are together, your students will be amazed how difficult it is to pull them apart! Have students design an experiment to determine how many Newtons of force are required to pull them apart.