Because particles are in constant motion, they often bump into one another. Usually, the particles try to spread out evenly in 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!)

Summary:

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

Materials:

• Balloon
• Vanilla extract
• Medicine dropper
• Clock, watch or stop watch

Student Procedures:

1. Use the pipette to place a drop of vanilla extract into the balloon.
2. Blow up 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 - and this time, have the balloon farther away.

Safety concerns: Be sure to follow all chemical and glassware safety rules that are specified by your teacher in all general laboratory experiences.

Analysis:

1. How does the smell escape from a balloon?
• 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 couple of weeks! Does it 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?