Download the printable Experiment Sheet here.
Condensation is the process by which water vapor (a gas) forms into liquid water. Condensation occurs because the water vapor molecules, which are far apart in a gas, move together as temperature cools or air pressure decreases.
Condensation is responsible for the formation of clouds. Even fog, which is a just a cloud near the ground, is a visible sign that condensation is occurring around you. Tiny bits of dust or smoke in the air allow water to clump together into visible droplets of water. As those water droplets grow they get heavier and fall as precipitation, or rain.
I this experiment, we create our own condensation and see the fog cloud it creates. Here we use very cold dry ice, or solid carbon dioxide, and add to water. This releases the CO2 gas and water vapor, which condenses rapidly inside the glass. We can catch some of the gas as it is released in a balloon!
This experiment also secondarily demonstrates release of gas, air pressure (inflation of the balloon), and sublimation of the dry ice (change from a solid carbon dioxide directly to gas form).
Glass (transparent) Bottle or jar
Dry Ice (solid frozen carbon dioxide) - have an adult assist with the dry ice to avoid cold burns - its really cold!
Tongs (for the dry ice)
- Fill your jar halfway with water.
- Carefully add a piece of dry ice to the water with your tongs and observe the reaction. A cloud should form of CO2 and water vapor in side the empty part of the jar or bottle.
- Place the balloon over the top of the jar and hold in place. Observe what happens.
- Remove the balloon and hold the end tight. When you’re ready open the end, and let your cloud escape!
Questions to consider:
- What does the dry ice reaction simulate in nature?
- Why doesn't the dry ice freeze the water? Where does the dry ice go?
- How/why did the balloon inflate?
- How can we observe condensation in nature?