Water can exist as a solid, a liquid, and a gas under everyday conditions. Both temperature and energy play important roles in this.

	The plume of steam above this cup of coffee is actually a cloud of tiny drops of water. The evaporation of water is an important mechanism for cooling the coffee; the recondensation of the water delivers the energy to the surrounding air.

Main Pages	Estimated time required	Link to Activities in the Manual
Exploring change of phase	30 minutes
What happens when water evaporates? and Making Dew With What We've Got	60 minutes	Phase Change #1
What is the temperature pattern of ice water as the ice melts?	45 minutes	Phase Change #2
About phase changes, humidity, and boiling	45 minutes
Discussion of phase change	30 minutes

Another page relevant to this section: Why study phase changes?

Materials needed for this section

• a glass jar, a can, a styrofoam cup
• thermometers*
• ice, ice water, hot water (please see local materials)
• liquid crystal sheets or thermometer*
• a glass vial
• pipette*