Tornado in a Jar

LSC in the House

Activity Time: 15 minutes
Recommended Grades: 1 - 8
Objectives: In this activity, we will model and understand the movements which create tornadoes. We also will be able to analyze the relationship between the size of a tornado and its speed.

  • Clear jar with lid (pint or larger)
  • Water to fill it 3⁄4 full
  • Liquid dish detergent
  • White vinegar
  • Red, blue, or green food coloring (two drops for quart jar, one for smaller)
  • Optional: Glitter (two tablespoons for a quart jar; adjust for smaller sizes)
  1. Fill the jar with water.
  2. Add liquid dish detergent, white vinegar and food coloring. Stir gently.
    a. Optional: Add glitter to better observe and analyze the tornado’s direction and speed.
  3. Tighten the lid.
  4. Using both hands, swirl the jar in a circular motion. A vortex (tornado) will appear.
  5. Stop swirling the jar contents and observe.
  6. Try the experiment with different speeds and directions. Can you make a skinnier or wider vortex? How does that affect the speed of the tornado in the jar?

As you move the jar in a circular motion, the fluid against the glass is being pulled into motion through friction. The fluid toward the center of the jar is slower to begin moving.

Eventually, all the water moves at the same speed. When you stop rotating the jar, the fluid continues to move. A vortex can be seen when the outer fluid slows down, but the inner fluid continues to spin quickly. In nature, this rotation occurs when there is a change in speed and direction between two different streams of wind. This is called “wind shear,” and causes a rotating column of air. If this column is caught in a supercell thunderstorm, the spin and speed of the column increases, and a tornado funnel cloud forms.



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