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Homework Help: Physics Toys

  1. May 30, 2004 #1
    Hi everyone... I need help finding a common household toy to use for a physics presentation. Unfortunately, I'm the last person so everyone else has used up a lot of the ideas! I can't use the following:

    -Bouncy ball
    -helium baloons
    -motor car
    -water gun
    -dart gun
    -drinking bird

    ...ANY ideas would be appreciated. Even if it's "how to do tricks" with a certain toy, that's acceptable too. I'd really need help. :)
  2. jcsd
  3. May 30, 2004 #2
    Laser guns?
  4. May 30, 2004 #3


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    How about a slinky?
  5. May 30, 2004 #4


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    Dearly Missed

    What about a "swing"?
  6. May 30, 2004 #5
    Anything with a spring in it. Like a mechanical pencil...

  7. May 30, 2004 #6


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    Paper airplane.
    Or one of those balsa wood airplanes with the propeller driven by a rubber band. (They do still make those don't they?)
  8. May 30, 2004 #7
    Thank you all for your replies!! I particularly like the paper plane idea, so I will be using that. Now I need a little more help (sorry!) but I'm almost finished. I need to think of another very simple demo to illustrate lift (aside from the actual toy, of course). There was classic one using a straw or something, but I don't really remember it now.

    Any ideas will do! Thanks again, you people are wonderful. :)
  9. May 30, 2004 #8
    Card lift with straw - demonstration of Bernoulli’s principle

    This one.

    • straw
    • paper clip
    • tape
    • two index cards
    • scissors

      How to do it

      Make a mark on the center of one index card.
      Cut a hole in the center of the index card just large enough to stick the straw through.
      Put the index card flat on the table. Put the straw into the hole.
      Holding onto the straw, tape it to the index card so that it won't move.

      Bend the paper clip so that one end is pointing up. Tape the paper clip onto the center of another index card with the end of the paper clip pointing up.

      Put the straw and index card over the point of the paper clip, turn the whole thing upside down, so the index cards are on top of the straw, and blow through the straw. The card doesn't blow off the straw.
      Turn the straw and cards over so that they're on the table and you're blowing down. Pick up the straw and top index card. If you keep blowing, both of the cards come with you.

      Here's why this phenom works: First you have to remember that there's air all around us and it pushes on everything in all directions. Air is pushing up and down on all sides of these cards.
      Then you have to think about what happens when you blow through the straw. When you blow through the straw you're making air move quickly toward the bottom index card.
      But before the air reaches the bottom card it moves really fast and is able to slip through the little space BETWEEN the two cards. Because the air slips in between the two cards, it doesn't have enough force to push down on the bottom index card.
      Now remember the other air that's pushing on everything in the room, well that air is still pushing along the bottom of the card. And because there's not much air pushing BETWEEN the two cards, the air along the bottom is able to push up and hold the two cards together.
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