Ms. Hohenemser

The students had an exciting and educational experience on Halloween watching some way cool demonstrations about rapid expansion and contraction and observing exciting changes that take place at extreme temperatures using dry ice and liquid nitrogen. We learned about sublimation which is what dry ice (solid carbon dioxide) does when it goes directly from being a solid to a liquid. We watched an egg getting sucked into an erlenmeyer flask and a pop can collapsing from the air pressure in the room. We heard the vibrations of dry ice “screaming” in a metal bowl, got startled by a film canister with dry ice in it popping loudly up to the ceiling, and watched a rubber glove expand with sublimating dry ice inside. Using liquid nitrogen, we froze a racquet ball and some flowers and shattered them. We then use the liquid nitrogen to freeze some marshmallows. It is an experience that will remain with students for years to come. Some of the lessons gleaned from the “show” include understanding how very very cold things can be boiling and evaporating and how powerful rapid expansion and contraction can be. (and of course how tasty frozen marshmallows can be). If you have good photos of any of these activities please e-mail them to me so I can add them to this post!