Schematic illustration of a boat sailing in the sea.

Dry Paper

Can Paper Stay Dry in Water?

 

Materials

  • tap water
  • plastic tub
  • sheet of paper
  • plastic cup

Try This

  1. Run tap water into the plastic tub until the tub is about three-fourths full.
  2. Crumple the sheet of paper and push it to the bottom of the plastic cup. Use enough paper so it will stay at the bottom when the cup is upside down.
  3. Hold the cup upside down and push it into the water. Be sure to hold the cup straight up and down, not tilted.
  4. Pull the cup straight up out of the water and, with dry hands, remove the paper. What happens to the paper?
Schematic illustration of a plastic tub with tap water, a plastic cup, and a sheet of paper.

What's Going On?

The paper did not get wet. Air surrounded the paper in the cup. When you pushed the cup into the water, the air was trapped in the cup. The trapped air pushed back on the water, keeping it from reaching the paper. If you had tilted the cup, the air would have escaped, and the water would have taken its place. In that case, the paper would have become wet.

Schematic illustration of holding the cup upside down and push it into the water.