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Under Pressure
Episode: Locks and Dams

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Grade level: Grades 5-10

A cubic foot of fresh water weighs 62.4 pounds. In this activity students observe what happens to the flow of water when it is under pressure.

Materials
  • 2 tall empty tin cans
  • nails
  • adhesive tape
Activity

  1. Punch three holes horizontally at the bottom of one can, about 1/2" to 3/4" apart. Cover the holes with adhesive tape. Ask students to predict what will happen when you fill the can with water and remove the tape. Will any of the streams be longer than the others?
  2. Punch three holes diagonally in the side of another can. Cover the holes with adhesive tape. Ask students to predict whether one stream will be longer than the others.
  3. Fill both cans with water. Tear off the tape on the can with the horizontal holes. Observe and discuss what happens.
  4. 4. Remove the tape from the can with the diagonal holes. Observe and discuss what happens.
Questions

Would this same principle of water pressure work with a balloon?
What household devices or appliances use the principle of water pressure to function?