Eighth graders are learning about "States of Matter" this fall, including through a Sublimation Lab with everyone's favorite spooky Halloween accessory, dry ice. Students donned gloves and goggles to handle the dry ice safely.
During the Sublimation Lab, science teacher Rob Kashima asked students to slide a piece of dry ice across a table, using a pencil to determine why it slides so easily. They can observe how the gas offshoot at room temperature makes for nearly frictionless surface tension.
Next, the students put a piece of dry ice in two different beakers, one with 100 ml of water and one in an empty beaker. They were asked to observe in which beaker the sublimation occurs more quickly and why. They also observed dry ice in regular water versus rubbing alcohol. The students saw that while the dry ice sublimates into gas while in water, it actually turns into a liquid in the alcohol but still remains so cold, it can freeze things like eggs on the spot--a form of cryogenic fluid!
Sublimation is the process of converting a solid into a gas without going through the liquid phase. With dry ice, there is no melting. Rather with the application of heat, even at room temperature, there is an endothermic reaction that produces carbon dioxide gas.