HONOLULU (HawaiiNewsNow) - It's time for another weird science experiment with Dr. V. Today's experiment deals with suspending water.
Dr. V Show: Suspending Water
July 6, 2010
Things you need:
- Empty jar or bottle
- Screen or plastic produce mesh (with small holes)
- Rubber band
- Card large enough to cover the mouth of your jar
- Bucket to catch the water
Cut a piece of screen large enough to drape over the opening of your jar. Stretch this screen over the mouth of the jar and secure it in place with the rubber band. Fill up your jar with water by pouring the water through the screen into the bottle. Notice that the water pours easily into the jar past the screen. Fill the jar almost to the top. Cover the mouth of the jar with your card and, holding the card in place, turn the jar upside down (over the bucket!). Slowly remove the card from the mouth of the jar. What happens to the water? With some practice, try carefully inserting a toothpick through the screen. You should be able to see it float up in the jar. Now, tip the jar to the side (over the bucket!). What happens to the water now?
So that's how it works…
This experiment demonstrates the power of cohesion. Cohesion is the force that attracts like molecules to each other and gives us surface tension. Try dipping a piece of screen in the water and pull it out. What do you see? Did you notice that there is water in all the little holes of the screen? This membrane of water is strong enough to keep the water from falling out of the jar. Once you break the surface tension, by touching the screen, or tipping the jar, the water gushes out!