20. Atmospheric Pressure

  1. Magdeburg hemispheres are evacuated in class and the strongest student challenged to pull them apart.
  2. A can with a few cc's of water is heated over a flame. When the can is filled with steam, it is removed from the flame and sealed tightly. Over a period of several minutes atmospheric pressure crushes the can as the steam condenses.
  3. A bottle of water has openings at the bottom and top closed with corks. When the bottom cork is removed no water flows out; it is held in by atmospheric pressure. But if the top cork is now removed, the water will come flowing out.

  4. A stick is placed on the lecture table overhanging the floor. Newspaper is laid on the lecture table over the stick. A sharp blow breaks the stick.