Solid, liquid, and gas are the three states of matter. Normally, matter moves between these three states with common transitions such as condensation, evaporation, and freezing. There are, however, ways they can skip over certain states!
What you need:
- Plastic cup (clear recommended but not required)
- Plastic wrap
- Rubber band
- Hot water
- Dry ice
What you do:
First, cut a hole in the bottom of the cup about the size of a quarter. Then, cover the top of the cup in at least two layers of plastic wrap. Secure it around the opening with the rubber band and make sure it is tightly sealed. Put on gloves for this next part; it’s dangerous to touch dry ice with bare hands! Add a piece of dry ice into the cup through the hole on the bottom of the cup, then pour in ¼ cup of the hot water. Now, tip the cup at a slight angle and tap on the plastic wrap. A puff of smoke will come out of the hole!
Questions to consider:
- Why do we use hot water?
- Where does the smoke come from?
- How long does the dry ice last in the cup?
Why it works:
When dry ice meets warm water, the heat causes it to begin to bubble and create the smoke. The bubbling is actually the process of sublimation! You know how water goes from being ice, to melting down to liquid water, to evaporating into vapor? Sublimation is when a substance skips that liquid phase, and goes straight from the solid phase to the gas phase. The smoke is actually the gas phase of the dry ice!