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7th Grade Core
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Because particles are in constant motion, they often bump into one another. Usually the particles try to spread out evenly over the area they are in. You may have discovered this when you tipped over a glass of milk and found the milk spread to an even depth on the kitchen table. When particles that have an odor try to spread out evenly, the odor spreads out with them. (Remember when you went past that dead skunk at the side of the road? You still got to "enjoy" the odor it left behind!)


In this activity, you are going to make observations which will demonstrate the movement of particles.


  • Balloon
  • Vanilla extract
  • Pipette
  • Clock, Watch, or Stop watch
Safety concerns: icon icon Be sure to keep all chemical and glassware safety rules. Remember not to put a stopper into any flask unless given direct instruction by your teacher.


  1. Use the pipette to place a drop of vanilla extract into the balloon.
  2. Blow up the balloon until it is as full as possible without popping it.
  3. Carefully tie the end of the balloon to keep the air inside.
  4. Lay down the balloon in front of you.
  5. Use a stop watch or clock to time how long it takes until you are able to smell the vanilla.
  6. Try the experiment again, this time with the balloon farther away.


  1. How does the smell escape from a balloon? Check out this possible explaination.
    • Think about a helium balloon and what happens to it if you tie the string to a chair and leave it overnight.
    • Think about what happens to a balloon you leave in one spot for a several weeks.
    • Does they change shape? How does this relate to the smell of vanilla?
  2. How does the distance between you and the balloon change the time it takes for you to smell the vanilla?

Review science safety rules here.

Get the plug-ins: Get Adobe Acrobat Reader , and Get Quicktime Player. (The Quicktime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 7th grade science core.

Updated October 24, 2008 by: Glen Westbroek

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