HONOLULU (HawaiiNewsNow)-Dr. V and Taizo are joined a special guest for help building a water tornado. It's a cool experiment that you can do at home. Check out the video!

Dr. V Show:  Tornado in a Bottle

Things you need:

• 2 empty 2-liter bottles
• Water
• Glitter or food coloring
• Duct tape
• 1-inch washer
• Many science education stores also sell a "tornado tube"

The experiment

Fill one of the bottles about two-thirds full with water. If you'd like, you can add food coloring or glitter to the water. Then place the washer over the mouth of the bottle and place the mouth of the other bottle on the washer (upside-down) and then, using the duct tape, fasten the two bottles and washer together. Try to tape it as tightly as possible so that the water doesn't leak out when you turn the bottles over. If you're using a tornado tube, twist both bottles into the tornado tube tightly.

Turn the bottles over so that the bottle with water in it is on the top. Notice that the water doesn't empty out into the bottom bottle. Move the bottle in a circular motion so that the water swirls on the inside. A tornado will form as the water from the top bottle flows into the bottom one.

How does it work?

When you first turn the bottles over so that the water is on top, the water doesn't flow down because there is no path for the air to enter the top bottle. The air needs to displace the water in the bottle on the top for the water to flow to the bottom bottle. Swirling the water causes the formation of a vortex, the shape of a tornado. This vortex allows the air into the bottle through the center of the vortex while the water pours down the sides of the bottle.

Hint: When you need to empty out bottles, creating this vortex by swirling the liquid around will actually let you empty your bottles much faster than just turning the bottle upside down and letting the water glub-glub out. This glub-glubbing happens when the air and water are forced to take turns moving in and out of the mouth of the bottle.