We pulled out more science nighttime fun. This time it was a glow-in-the-dark Cartesian diver we affectionately named “Squiddy”. My daughter and I built his insides with a plastic pipette and a hex nut and tested him out in a glass of water. We then fitted his squid body over our pipette “guts” and put him into a 1 L. pop bottle. With the pipette partially filled and bottle all the way filled with water and capped, we could easily control Squiddy and make him go up and down by squeezing the bottle gently.
Then we used a black light to really energize his glow and took him upstairs to try to trick my son. I told him that Squiddy could tell the future if you asked him “yes”/”no” questions…he would move up for “yes”, down for “no”.
He didn’t buy it even for a minute, but loved playing with it in the dark. Both kids deduced how it worked…more air in the pipette sends him up, squeeze the bottle and air comes out of the pipette and he sinks.
Then we played with the black light for awhile, checking how things looked.