Calcium

An experiment that has always fascinated me is observing what happens when CO₂ is bubbled into limewater (which is a saturated solution of calcium hydroxide).^1-2 This experiment can be carried out by blowing bubbles of exhaled breath (which contains roughly 4% CO₂)³ through a straw into limewater.

The chemistry demonstration called the self-carving pumpkin¹ is a blast (no pun intended) to conduct around Halloween. To prepare this experiment, a jack-o-lantern face is carved into a pumpkin, but the eye, nose, and mouth pieces are saved. These pieces are then gently placed back into the holes in the pumpkin.

I recently tried an experiment in class that works well as a chemistry demonstration for Halloween. In fact, I recently performed it at our annual Halloween / National Chemistry Week chemistry demonstration show. The experiment is very easy to carry out. I call it “The Devil’s Milkshake”. Check it out in the video below.