Of all the science experiments we’ve done for Hanukkah this year, and last year, this one is probably the easiest to set up and demonstrate. It also turns into a very satisfying toy.
The Cartesian Diver (named after René Descartes) is not only easy to build and fun to play with, it also opens the door to discussions about fluid pressure, fish anatomy, the foundations of modern science, and even a little philosophy.
The instructions for this experiment are simple (materials are in bold):
- Fill a plastic soda bottle almost to the top with water.
- Cut a drinking straw in half, and bend one half in the middle.
- Use a paperclip to keep the bent straw from unbending.
- Form a blob of modeling clay onto the exposed curve of the paperclip.
- Drop your ‘diver’ into the bottle of water.
- Tightly close the lid.
- Squeeze the bottle.