Good educational and fun experiment and activity for school classes, home school, scouts and any other group, stimulating kids interest to physics and study

• Note: you have to take the food-security ring off of your bottles to get these to catch the threads; And 2 liter soda bottles or other 2 liter bottles are suitable to use.Remove the small plastic ring on the bottle to tighten it-to prevent water leakage.
• Convenient for using: apply the tool to connect 2 bottles with approx. one third water, then shake them for 4 to 5 times in horizontal direction, and you will see your vortex spin in the bottle
• Fill the water first to two-thirds of an empty bottle, then use the bottle connector to connect the two bottles, and shake it vigorously for three to five times. The tornado you expect is formed, so easy.You can add dye or laundry detergent to the water in the bottle so that the resulting tornado will have different colors and bubbles, which creates even more fun.
• Size:4.5*3*3cm
• For kids, it is the perfect gift for Christmas gifts, birthdays, and other holidays.