This experiment recreates a tornado inside a bottle. Take two 2-liter plastic soda bottles and wash them before filling one of them two-thirds full with water. Optional food coloring can be added to the bottles as well to make the tornado more visible. Connect the two bottles with duct tape and a washer. The experiment is performed by swirling the bottle that contains the water in a circular motion, then tipping the bottles so that the water-filled bottle is on the top. As the water flows from the top bottle to the lower one, a vortex similar to a tornado will be created. As a variant, add a small amount of vinegar and dish soap to the water. These liquids lower the surface tension of the water and create a move vivid tornado vortex in the swirling water.
With the help of just an 8-ounce jar with lid, the students can easily recreate a tornado in the classroom. Just rinse and clean the jar and fill it about three-fourths with clear water, adding one teaspoon each of liquid soap and vinegar. Now, cover the jar with a lid and swirl it vigorously in a circular motion. This will lead to the formation of a mini tornado vortex at the center of the jar. However, this experiment will not last as long as the demonstration described in the previous step.
Made from a cardboard box, students cut square panels from each side of the box, and replace them with clear plastic or plexiglass so they can see inside the box. The box is then painted black, and 1-inch wide slits are cut vertically on each corner, from the top to the bottom of the box. Finally, a small hole is cut in the top of the box, and a battery-operated computer cooling fan is placed over the hole. Orient the fan so that it blows upward, away from the box. When students put a bowl filled with water and dry ice in the box and turn on the fan, the air drafts create a swirling motion as they are pulled through the box. The steam from the dry ice creates a tornado vortex visible inside the box.
A similar tornado simulator is constructed from two 5-gallon pails. The students paint the inside of the pails black, cut a viewing window in the side of one of the bucket, and cut ventilation fins that look like fish gills around the perimeter of the other bucket. In the bottom of the bucket with the viewing window, students cut a 3-inch hole for a battery operated ventilation fan, and a 2-inch hole for a flashlight. The experiment is performed by placing a bowl filled with dry ice and water at the bottom of the bucket with the fins. The two buckets are taped together to create a large enclosed space inside of them. When the fan and flashlight are placed over the holes on top of the upper bucket and the fan is turned on, students can look through the viewing window and see a tornado-like vortex formed as the fan pulls the dry ice steam upward and out of the containers.