Tornado Tube Connector for Plastic Bottles

thingiverse

This part will allow you to connect two water bottles to each other and then, when you turn it upside down and give it a spin, you can make a tornado as the water pours from one into the other! This is a great way to teach the power of something you can't see - air - as it gets in the way of the water. The flow will be really slow until you give it that all important spin, pushing the heavier water out to the sides of the flask and creating a tube for the air to go straight up the middle.