Courtesy of the American Plastics Council
Create your own whirlpool, also called a “water vortex.”
2 empty one-liter soda bottles, rinsed out and with labels removed
1 rubber or steel washer with a small hole in the center – washer should be the same width as the tops of the bottles
1 roll of strong electrical, or duct, tape
1. Tape the washer to the top of either bottle. (Make sure the tape doesn't cover the hole in the washer.)
2. Fill that water bottle three-fourths full of water.
3. Place the empty bottle upside down on top of the washer. Tape the bottles securely together.
4. Turn the bottles over so the one on top holds the water. Quickly swirl the bottles in a big circle several times and place the bottom bottle on a flat surface.
When you stop, the water should start swirling down in a tornado!