Mind Control or Cartesian Diver?

Is it mind control or just a clever science trick? It’s a classic science experiment using an eye-dropper, a soda bottle filled with water, and some great showmanship. Explore the science and physics of Cartesian divers while amazing your friends with your telekinetic powers.

This experiment is named after Ren Descartes (1596-1650), a French scientist and mathematician who used the diver to demonstrate gas laws and buoyancy.

Hold your Cartesian diver bottle with one hand and squeeze and release. The diver sinks and floats based on the pressure (if you are squeezing) or decreased pressure (when you release) when holding the bottle of water. Increased pressure forces water up into the diver, compressing the air at the top. The increased mass of the diver will cause it to sink.  Releasing the squeeze decreased the pressure on the air at the top of the eyedropper, and the water  is forced back out of the diver.

Want to make your own Cartesian Diver or Squidy Diver? Check out the experiment.