Add some action to any science lesson thanks to this fun Twister Tube! Create a tornado in a bottle in a snap and keep curious minds engaged in a fun and interactive way. Simply fill an empty plastic bottle 2/3 full of water then attach the Twister Tube. Attach a second empty bottle to the other end of the Twister Tube, then quickly turn over the bottles so the one with water is on top. Now give it a shake in a circular motion and watch your tornado brew! Great for science tutorials, this Twister Tube illustrates kinetic and potential energy, as well vortex action. Plastic. 2" x 1 1/4" diam.