Weird Science: Keep paper dry in water

HONOLULU (HawaiiNewsNow) - It's time for another weird science experiment. Today, Dr. V is going to show us how to keep paper dry in water!

Dr. V Show: Keep Paper dry in Water

September 14, 2010

Things you need:

  • Cup
  • Paper
  • Large bowl
  • Water

The experiment

Please perform this and all experiments under the supervision and with the assistance of an adult. Crumple up some paper and put it in the glass so that it's at least half an inch below the rim of the glass. Put enough paper in the cup so it won't fall out when you turn the cup upside down. Fill your bowl with water so that the height of the water is almost the same as the height of the cup. Turn the glass upside down and slowly immerse the cup in the water. Now remove the glass from the water without tilting it. Check the paper in your cup. How does it feel?

How does it work?

When you put the cup straight into the water, there is nowhere for the air to escape. So as you push the cup into the water, the air pressure keeps the water out of the cup. The air needs a way to get out of the cup to make space for the water to go into the cup. Try putting the cup into the water at an angle. Now what happens? Because the air is able to escape out of the cup, the water is able to enter the cup.

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