Soda Bottle Vortex

Adult Supervision Required...

Tornadoes are powerful, twisting winds are the fastest and most dangerous on Earth. At the center of the tornado is a spinning column of air called a vortex. Some tornadoes even have more than one vortex. This project lets you see what a tornado's vortex looks like. So grab some supplies, and give it a whirl!

Materials
2 2-litre pop bottles with caps
Duct tape
Silicon caulking
Water
Drill (get an adult's help with this)
Food coloring (optional)
Plastic confetti (optional)

Note: Some science stores sell a "Tornado Tube" adapter which allows you to connect the two pop bottles without drilling or gluing. 

Directions
1. Take the caps off both the pop bottles.
2. Get an adult's help to drill a 1/2" hole in the center of each cap.
3. Place the caps together and put a bead of silicon around the hole to seal it. Let dry.
4. Wrap a piece of duct tape around the outside of the two caps to firmly join them together. 
5. Screw the double cap onto one of the pop bottles.
6. Fill the other pop bottle about 3/4 full of water. Add food coloring or plastic confetti to the water if you want.
7. Screw the empty bottle onto the top of the bottle containing the water.
8. Hold the duct-taped area with one hand and the bottom of the bottle with the other hand.
9. Turn the bottles upside-down and swirl them in a few quick circles. A vortex forms as the water drains into the lower bottle.