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Sometimes as we look at the world around us, we see movement without any evidence of why it happens. Consider the following and propose your hypothesis of what causes each.
  • 14 k gif image of clouds moving in the skyHave you laid on your back and watched clouds moving in the air above you?
    1. Did you observe anything pushing these clouds?
    2. Have you ever wondered what makes the clouds move through the sky?
  • 47k gif image of a flashlightNow shine a flashlight in a dark room and ask yourself each of the following questions?
    1. Do you see small particles in the air?
    2. Are any of these particles moving?
    3. What could make a dust particle move?

To explore how scientists explain the particulate nature of matter, you might enjoy visiting "The Atom's Family - Phantom's Portrait Parlor." The section "Phases of Matter" has a fun way to compare how temperature changes the particle motion of solids, liquids and gases.

Now it is time to experiment and prove that

Purpose:

You are to demonstrate the effect that temperature has on particle motion and volume.

Background:

You have already learned that the particles that make up matter are in constant motion. By increasing the temperature or energy in matter, the molecules speed up and the volume increases. The opposite is also true... by decreasing the temperature or energy in matter, the molecules slow down and the volume decreases.

Materials:

  • Balloon
  • String
  • Marker
  • Bunsen burner
  • Matches
  • Two meter sticks

Procedure:

  1. Inflate the balloon and tie off opening. (Use no more than eight breaths of air to fill up the balloon.)
  2. Wrap string around the widest part of the balloon.
  3. Use a marker to mark the length of the string wrapped around the balloon.
  4. Tie balloon to the end of one of the meter sticks.
  5. Light the Bunsen burner.
  6. Use a meter stick to hold the balloon at least 500 cm (1/2 a meter) above the Bunsen burner flame.
  7. After the balloon has been above the flame for five minutes, move the balloon away from the flame and quickly measure the width of it again.

Data:

Volume at start: Volume after heating for five minutes:
   

Analysis:

  1. Did the volume of the balloon increase or decrease after it was held above the flame?
  2. What kind of an experiment would you suggest doing to prove that cooling the balloon will also change the volume?

Review science lab safety rules here.

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Updated August 11, 2005 by: Glen Westbroek

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