Module 1: Measurement and Units

EXPERIMENT 1.2

Air Takes Up Space

Supplies :

· A tall glass

· A paper towel

· A sink full of water

· Safety goggles

1. Fill your sink with water until the water level is high enough to submerge the entire glass.

2. Make sure the inside of the glass is dry.

3. Wad up the paper towel and shove it down into the bottom of the glass.

4. Turn the glass upside down and be sure that the paper towel does not fall out of the glass.

5. Submerge the glass upside down into the water, being careful not to tip the glass at any time.

6. Wait a few seconds and remove the glass, still being careful not to tilt it.

7. Pull the paper towel out of the glass. You will find that the paper towel is completely dry. Even though the glass was submerged in water, the paper towel never got wet. Why? When you tipped the glass upside down, there was air inside the glass. When you submerged it in the water, the air could not escape the glass. Thus, the glass was still full of air. Since air takes up space, there was no room for water to enter the glass, so the paper towel stayed dry.

8. Repeat the experiment, but this time, be sure to tip the glass while it is underwater. You will see large bubbles rise to the surface of the water, and when you pull the glass out, you will find that it has water in it and that the paper towel is wet. This is because you allowed the air trapped inside the glass to escape when you tilted the glass. Once the air escaped, there was room for the water to come into the glass.

9. Clean up your mess.