Remove any labels from the outside of the water bottle. Add water to the water bottle until it is almost full. Add 1 teaspoon of salt, and shake the bottle with the lid on it until the salt dissolves in the water. Remove the lid from the bottle.
Add 1 drop of dish detergent and 1 drop of food coloring. Add 1 tablespoon to 2 tablespoons of baking soda. The baking soda and food coloring will help students see the water currents in the vortex that represent air currents of a tornado.
Put the lid on the bottle tightly. Move the bottle in a swirling motion, creating a vortex.
Add confetti or small, plastic objects to the water to help students see the power the vortex of a tornado has to draw objects around it into its center. The objects represent debris, cars, houses and other materials that a tornado sweeps into its center along its path of destruction.