# Steve Spangler Science

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# Tornado in a Bottle - Tornado Tube

You'll amaze your dinner guests with this cool trick.

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How long does it take to empty a soda bottle full of water? You'll amaze your dinner guests and explore some of the scientific properties of air and water when you learn how to empty a full bottle of water in just a few seconds!

###### Materials
• Two plastic 1-liter bottles
• Water
• Bowl or other container
• Stopwatch or watch with a second hand to record your times
• Duct tape
• Metal washer
• Pitcher

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# Experiment

1. Remove any label from the soda bottle so you have a clear view of the inside.
2. Fill the soda bottle to the top with water. If you do not have access to a sink nearby or you don't want to move the dinner party to the kitchen, use a large pitcher to fill the bottle.
3. Here's the challenge: How long will it take to empty all of the water in the bottle into the pitcher on the table? Record your prediction on a piece of paper.
4. Without squeezing the sides of the bottle, turn it over and time how long it takes to empty all of the water. You might want to repeat this several times to validate your results. Do the test 3 times and average the results. Keep a table of your results and call this method the Glug-Glug Method. Be sure to use the same amount of water for each of the trials.
5. Fill the bottle to the top with water just as you did before. However, this time swirl the water by moving the bottle in a clockwise or counter-clockwise motion while the water is pouring out. Keep swirling the water until you see the formation of what looks to be a tornado! The water begins to swirl in the shape of a vortex and flows out of the bottle very quickly.
6. Time this method as you did before, only call it the Vortex Method. Repeat the test several times and average the results. Which method allows the water to exit the bottle more quickly?

Now it's time to create a Tornado in a Bottle that you never have to refill.

1. Fill a one-liter bottle to the top with water.
2. Find a metal washer that fits flush (or as close as possible) onto the mouth of the one-liter bottle.
3. Place another one-liter bottle on the water-filled one-liter bottle so that the washer sits in place between the two.
4. Use duct tape to tape the two bottles and washer in place. Make sure that the connection is as sturdy as possible and that the duct tape does not allow any bending.
5. Turn the apparatus over so that the filled bottle is on top and swirl the water. The water will form a tornado and drain into the other bottle. You can do this as much as you want without refilling it!

Twist of Color - Try adding 2 ounces of colored lamp oil to the water. Lamp oil is available at most department stores where oil lamps are sold. The oil will float on the surface of the water since oil is less dense than water. When the oil and water swirl together, the less dense oil travels down the vortex first and creates a "colored tornado" effect.

Bubbly Vortex  - Try adding a squirt of dish soap to the water. As the twister drains from one bottle to the other, the top bottle will fill with soapy bubbles! This is cool and shows that as the bottom bottle fills with water, the top bottle is filling with air.

Styrofoam Storm - Add some debris to your twister. You can use small items like confetti or glitter (we've even heard of people trying Monopoly hotels), but our personal favorite is tiny styrofoam balls. The balls float but are sucked into the bottom bottle from the power of the spinning vortex. It's really cool to look at!

# How Does It Work?

If you've ever seen a dust devil on a windy day or watched the water drain from the bathtub, you've seen a vortex. A vortex is a type of motion that causes liquids and gases to travel in spirals around a center line. A vortex is created when a rotating liquid falls through an opening. Gravity is the force that pulls the liquid into the hole and a continuous vortex develops.

Swirling the water in the bottle while pouring it out causes the formation of a vortex. The vortex looks like a tornado in the bottle. The formation of the vortex makes it easier for air to come into the bottle and allows the water to pour out faster. If you look carefully, you will be able to see the hole in the middle of the vortex that allows the air to come up inside the bottle. If you do not swirl the water and just allow it to flow out on its own, then the air and water have to essentially take turns passing through the mouth of the bottle, thus the glug-glug sound.

## Customer Reviews

love the explanations Review by Annalisa Bottacin

I always appreciate the straight forward explanations for the various experiments. Easy to comprehend for the younger students and often lead to good questions from the older students. Thanks!

(Posted on February 9, 2011)

Best Science Fair Project EVER Review by Angeli

My friends and I did this for our science fair project and it is awesome. Easy, fun, and a great idea.

(Posted on December 16, 2010)

From an Old Scientist Review by Lance Eggenberger

These are great demonstrations that really teach sciectific principles. They are age based, so in the class room they would be great. The presentation on TV is even greater.

(Posted on November 7, 2010)

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