Attach your tube to two 2-liter bottles and give it a swirl. Watch your vortex spin in the bottle. Cyclone tube is 2 inches long and will be chosen randomly from 4 translucent colors (yellow, green, blue and red). You are buying just the cyclone tube. This is a great educational and fun experiment and activity for school classes, homeschoolers, scouts and any other group. Create a tornado from two 2 liter plastic bottles, water and a colorful plastic connecting tube.