Last Sunday at the Pikes Peak Marathon Block Party, a little girl wearing a pink dress visited the Cool Science booth with her family. All of them, the mom, dad, three sisters, and brother, were captivated by dragon’s breath, cereal that gives you the ability to blow smoke like a dragon. Well, not EXACTLY smoke. It’s actually a cloud of water vapor formed because the cereal is dipped in liquid nitrogen, which is -320°F.
At first the family was hesitant to put the cold-as-the-planet-Neptune cereal in their mouths, but finally the brave mom stepped forward. After she showed her family that the coast was clear and the fun you can have blowing clouds, the brother and two older sisters were eager to get their hands on some dragon’s breath of their own. The littlest sister was still not sure she wanted to commit to the experience, but her eyes betrayed her fascination with the science.
After the dragon’s breath, the family was able to make their own penny puzzles. When pennies made of zinc are cooled in liquid nitrogen, they become brittle and break into tiny pieces, which make excellent puzzles. This doesn’t happen to copper pennies (those made before 1982) because copper remains strong even when bellow -320°F.
The little girl was still apprehensive about experimenting with liquid nitrogen, however.
So, Cool Science showed her all the amazing things you can do with the substance. We showed her that it flash boils instantly when it hits the ground, leaving nothing but a small cloud. How it rolls along the table on a cushion of gas thanks to the Leidenfrost effect. And that its low viscosity means the liquid spins around in a beaker really fast—even when the beaker is upside down.
By the end of her visit, the little girl’s curiosity and wonder at the experiments may have sparked her future career as a scientist!
-posted by Joshua