DiscoverHover CURRICULUM GUIDE #8 - Experiment
© 2004 World Hovercraft Organization
NAME

DATE

PARTNER'S NAME

EXPERIMENT 8.1

Equipment:
  • 2 thick books or binders
  • 1 sheet of notebook paper
  • 1 straw


    • Place two books or binders parallel to each other on a table and approximately 3” [76.2 mm] apart. Place the sheet of paper over the gap between the books, with the edges of the paper resting on the inside edges of the books. Using the straw, blow underneath the paper as hard as possible. The paper will be pushed down in the middle toward the table. The increase in air speed underneath the paper causes a decrease in pressure. The higher pressure on the top of the paper pushes the paper down toward the table.


    EXPERIMENT 8.2

    Equipment:
  • Strip of notebook paper or newspaper, about 2" [50.8 mm] wide and 10" [254 mm] long
  • Book
  • Paper clips

    • The force that lifts an airplane and holds it up comes from air which is forced apart by a moving wing.

    Make an airfoil (wing) by placing one end of the strip of paper between the pages of the book so that the other end hangs over the top as shown in the above diagram. Move the book swiftly through the air or blow across the top of the strip of paper. Notice that it flutters upward.

    Hold the book in the breeze of an electric fan so the air blows over the top of the paper and observe what happens.

    Take the strip of paper out of the book. Grasp one end of the paper and set it against your chin, just below your mouth. Hold it in place with your thumb and blow over the top of the strip. The paper rises. Try the same thing after you have fastened a paper clip on the end of the strip. See how many paperclips you can lift in this way.

    It doesn't matter whether you move the air over the strip of paper by blowing or whether you move the paper rapidly through the air - either way it rises. How does this relate to what causes the wings of aircraft to produce lift?

    EXPERIMENT 8.3

    Equipment:
  • 2 empty soft drink cans
  • 30 or more plastic drinking straws

    • Another way to demonstrate Bernoulli’s principle is to lay about 30 drinking straws parallel to each other on a tabletop, then place two empty soft drink cans on top of the straws as shown in the picture. Using one of the straws, blow as much air as you can between the two cans and watch what happens. Get a partner with a second straw, and this time each blow along the outside surface of each can. Can you explain why the cans move the way they do?


    www.shawsciencezone.com

    EXPERIMENT 8.4

    Equipment:
  • A long vacuum cleaner hose or other similar hose (at least 1" [25.4 mm] in diameter)
  • Small bucket filled with sawdust or paper bits from a paper hole punch

    • This experiment will help to dramatically demonstrate Bernoulli's Principle, but be forewarned -- it can make quite a mess! Place the bucket of sawdust/paper scraps on the floor, with one end of the hose in the bucket. Keeping one end of the hose in the bucket, swing the other end rapidly over your head like a lasso. (Watch out for low hanging light fixtures!) The sawdust/paper scraps will come shooting out the top of the hose!

    When swinging the hose around over your head, the increased air speed at that end of the hose results in a corresponding decrease in air pressure. This results in the higher air pressure at the other end of the hose (the end in the bucket of sawdust/paper scraps) pushing the paper through the hose and out the swinging end!