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How does a Tornado Work?

Project Impact
How a Tornado Works

Before thunderstorms develop, a change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. Rising air within the thunderstorm updraft tilts the rotating air from horizontal to vertical. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation.
  1. A large, thermally stratified situation develops in the atmosphere, with plenty of hot, humid air trapped beneath cold, dry air.
  2. For some reason, the "cap," (the stable layer of air between the hot and cold air) is disturbed. The disturbance can be caused by an upper-level air disturbance, or the arrival of a front (defined).
  3.  As the lower-level air rises, it expands in the reduced air pressure aloft (air pressure drops as altitude increases), and it cools. Eventually, the cooling causes the moisture to condense (defined).
  4. Condensation releases latent heat, warming the air, making it buoyant, and causing it to rise quickly (at speeds up to 150 mph). By now, the cloud has formed into a thunderstorm. Upper-level winds tilt the thunderhead to create the anvil at the top.
  5. The thunderstorm may die out in intense rain and/or hall. Or it may spawn a tornado.
  6. Interactions between air at various altitudes, humidities and temperatures causes rain, lightning, air circulation and an intensification of the rotating updraft, called a "mesocyclone." Low-level wind helps cause this rotation, which is almost always counter-clockwise (seen from above) in the Northern Hemisphere.
  7. A tornado may form below the mesocyclone. As the spinning column of air narrows, it rotates faster and extends higher into the storm.

Twister in a Bottle!
How to Make a Homemade Tornado

You can create a tornado of your own quite easily. Here are two recipes.

Method 1: Take two 2-liter soda bottles, fill one with water, and purchase an item called a Tornado Tube. The tube connects the bottles so that one is upside down. (If you don't want to buy a tornado tube, just use good old-fashioned duct tape.) Simply turn the bottle with water to the top, give the bottles a twist, and a vortex (a rotating circulation) will flow into the lower bottle.

Method 2: You can also make a vortex by filling a mayonnaise or canning jar about three-quarters full. Add food coloring to water, along with a teaspoon of liquid dishwashing detergent and a teaspoon of vinegar. Tighten the lid, shake the jar vigorously, and then give it a good twist. The liquid will form a vortex that looks like a small tornado. It will even lengthen and then retreat like a real tornado.