Teach kids about vortexes with the Soda Bottle Tornado Tube. Needs two 2 - liter soda bottles (not included). Fill one bottle 2/3rd's full with water attach it to the tube and then attach a second empty bottle to the other end of the Tornado Tube. Place the assembly on a table with the empty bottle down and shake the full bottle in a circular motion. Add food coloring or glitter to the water for special effects. Use only with plastic bottles! Imported.