# Vortex Racer - Tornado in a Bottle

## Use the vortex secret to create a tornado in a bottle

Take the Quick Pour Soda Bottle Challenge using just a few 1-liter soda bottles, a bucket of water, a stopwatch and a little creativity. How long does it take to empty a 1-liter soda bottle? Some people might squeeze the bottle, but that's cheating. What if you could find a way to allow water to leave the bottle at the same time air fills the bottle? It's as easy as creating a swirling vortex with the twist of your hand.

### Materials

• 1-liter soda bottle
• Water
• Stopwatch (a watch with a second-hand will work, too)
1. Fill a 1-liter bottle with water.
2. Before pouring the bottle out, record how long you think it will take to pour the water out in seconds.
My guess: ______ sec
3. Without squeezing the bottle, try to pour it out as fast as you can into a bucket or a sink. Repeat this 3 times and record the times in seconds.
Time #1: ______ sec    Time #2: ______ sec
Time #3: ______ sec
4. Can you think of a way (no squeezing) that you can empty the bottle faster?  When you think you have come up with a way, time your new method and record your times in seconds.
Time #1: ______ sec    Time #2: ______ sec
Time #3: ______ sec
5. Now that you've tried your method, I'll let you in on my secret method to quick pouring.  Fill the bottle to the top.  This time, when you turn the bottle over give it a swirl.  Make sure that you notice the swirling vortex that has formed inside of the bottle.  Again, repeat this 3 times, recording all 3 times in seconds.
Time #1: ______ sec    Time #2: ______ sec
Time #3: ______ sec

### How does it work?

The swirling tornado in the bottle is referred to as a vortex, which is a type of motion that causes liquids and gases to travel in spirals around a center line. Swirling the water in the bottle while you are 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.

How Does a Vortex Start?

Vortices (that’s the plural form of vortex) form in many ways. A vortex can be 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. Only a small amount of swirling action is needed to start the vortex. You can see a vortex form over the drain when you let the water out of a bathtub. You’ll notice that the water spins away from the center of the vortex. The rotating motion of the water pushes it outward as it spirals into the drain. The vortex will continue until the water is gone, unless you cover the drain or block the rotation.

Water running down a drain will rotate in a different direction in the Northern and Southern Hemispheres. If water runs out from a perfectly symmetrical bathtub, or toilet bowl, in the Northern Hemisphere it would swirl counterclockwise, and water would spin clockwise in the Southern Hemisphere. This phenomenon is due to the Coriolis effect, which is the influence that the Earth’s rotation has on any moving body of water or air. This explains the counterclockwise or clockwise rotation of water as it flows down the drain.

The Coriolis Effect - How Does It Affect the Spin of the Vortex in the Bottle?

In September of 1994, Ms. Brunner’s sixth-grade science class at Holden Middle School in Holden, Missouri, decided to research the Coriolis effect on their own. The students wanted to know if the direction of the swirling water really does change depending on whether it is in the Northern or Southern Hemisphere. Indeed, the students could test the Northern Hemisphere theory right in their classroom, but taking the whole class on a field trip to South America would be impossible!

Ms. Brunner was not going to let a few thousand miles stand in her way. While she didn’t have the resources to physically take the class to South America, she could take the students anywhere in the world by means of a computer and the Internet. She decided to use the Internet to post her students’ question and hope that a scientist or group of scientists who specialized in fluid dynamics could supply some answers.

The question was posted on an information forum on the Internet at 5:50 pm, on September 6, 1994. Within two hours the first response came in from South America. In Columbia, the reply stated, “Water goes down the drain in the opposite direction than it does in your Northern Hemisphere.” Then, from an observer in Ecuador, very near the equator, Ms. Brunner’s students learned that water goes straight down the drain. There was not much in the way of a scientific explanation, just observations made by other human beings in different parts of the world. This Information Superhighway exercise demonstrated to the students that they were actually contributing to the field of knowledge and experiencing firsthand the thrill of scientific exploration.

However, the story doesn’t end here. During the next four days, scientists from all over the world replied to the students’ questions. Comments and theories came from Arkansas, Indiana, Louisiana, Massachusetts, Missouri, New Jersey, and South Carolina. Replies also came from Argentina, Australia, Brazil, Columbia, and Ecuador. At the outset, the students probably never imagined calling a professor at MIT or Loyola University or a government agency for an answer to their seemingly simple question. Yet, scientists from all over the world responded to their scientific inquiries. Generally speaking, the scientists could not agree on any theory. Instead, they exchanged ideas and suggested ways for the students to test their hypothesis. Indeed, the students learned firsthand that theory guides and experiment decides. Ms. Brunner firmly believes that the students learned more about the true nature of science from their experience than any textbook could ever supply.

Finding a Vortex in Nature

A vortex can also form behind a blunt object sitting in a stream of flowing liquid or gas. For example, a vortex may form behind a rock in a creek. The flowing water splits into two streams as it hits the rock. When these two streams meet on the other side of the rock, they will be flowing toward each other. Some rotational action may occur and a vortex may form. This vortex is called a whirlpool.

You can think of the wind blowing (or flowing) around a building in the same way. When the two air streams meet behind the building, they may form a vortex. Have you ever seen the leaves on the side of your house blow around in a circle for a few seconds? That so-called dust devil is a vortex.

Vortices can form in water or air when two streams flow against each other. In the atmosphere, winds moving in two directions with different temperatures can affect the weather. They may form local vortices known as tornadoes or very large, regional vortices known as hurricanes.

 Further the experiment... Ray Reddick    -  August 3, 2010 This user gave 5/5 stars You should time the bottle emptying first by swirling the water clockwise (looking from the top) and then repeat the experiment swirling the water counterclockwise . Does it make a diffeerence? If you know anyone in Austrailia email them and have them repeat the experiment. It is surprising how strong the motion of the earths rotation is on a liquid ( including air). Ask the weather person about this effect on air. Then ask which way a tornado rotates and why. There are two reasons why a tropical storm is called a 'Tropical Depression" One is because the Barometric pressure is lower than outside the storm area. For the other look at the surface of a whirlpool. The surface of a liquid is always flat isn't it. Try stiring a bucket of water in one direction at a certain rate then stop stiring and note how long the motion continues. Repeat in the opposite direction. Enjoy.

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