Did you know children can try different Cartesian diver experiment variations? We recently were interested in the ideas behind this science. This post includes some information from the Steve Spangler Science site, as well as photos and a video of our own attempts. Children will be able to think of additional variations and try them out. The experiments that work and the ones that need improvement all help us learn more about science. Not to mention, they keep children busy and engaged and away from screens!
Variations of the Experiment
In this experiment, a plastic bottle is filled to the tip top with water. An eyedropper is really the only other item needed to make this work. Fill it about 1/4 full of water. Younger children will need assistance with getting the lid on while keeping the water in the dropper. With the lid securely in place, pressure is added to the outside of the jar. The eyedropper sinks. When the jar is released, the eyedropper floats again. If the bottle is about one liter, a trick can be played as it is easier to squeeze pressure on the bottle (and therefore compress the air in the eyedropper) as it will appear to be magic when the eyedropper goes down. Observers focus on the eyedropper, not the person’s hand, of course. Slight of hand!
We tried changing one eyedropper to be a jellyfish, as well as using more eyedroppers in a larger bottle. We found the more that was added to the eyedropper the more difficult it was to submerge with pressure. The explanation for how this works is available at this link.
Below is a video of our trial of this experiment. We tried one eyedropper “dressed” as a jellyfish by adding some yellow plastic bag cut into little strips and tied with a twist tie. Then we tried 3 plain eyedroppers in a large bottle, which took some pressure!
This is another experiment on the Steve Spangler site showing 5 pipettes with a buoyancy twist on this idea. Children will have even more ideas to try!
Thank you for reading, Carolyn
See also more free printables and activities: