Evaporation is the process by which water changes from a liquid to a vapor. The Sun's energy warms water droplets until the water becomes a vapor and rises into the air. When water vapor (or droplets) come together in the sky, they form clouds.

Condensation is the process by which water vapor cools and becomes a liquid again.

Precipation is the process by which condensed water builds up in clouds and falls to the ground as rain, sleet, snow, or hail.

### Daily Weather Calendar

With daily weather calendars, your students will learn important scientific observation skills! Prepare a large blank class calendar and smaller individual calendars for each student. Each day, give two students the opportunity to serve as data collectors. Data collectors should work together to check the rain gauge and an outside thermometer. The data collectors write their findings on the class calendar, while everyone updates their own individual calendars. Use your weather calendars as a basis for math story problems and as a writing prompt. For example, ask students to describe the weather in detail to establish a setting or mood.
–Bob Krech, Dutch Neck School, Princeton Junction, N.J.

### Water Cycle on a String

Your students can create their own manipulative models of the water cycle using inexpensive plastic beads. After you have talked about the water cycle as a class, give each student an equal number of blue, yellow, and clear beads to string. Each color will represent a part of the water cycle. Water is blue, evaporation is yellow (like the Sun), and clear beads represent the rain. The children can use the beads as a memory device to help them remember what they have learned about the water cycle.
–Sue Lorey, Grove Avenue School, Barrington, Ill.

### Measuring a Month of Rain

How much does it rain where you live? How often? Encourage your students to learn about the weather and the environment of your region by tracking and graphing a month's worth of rain or snow. To measure rainfall, make a simple rain gauge. Use a small can, place it away from trees or buildings, and secure it with rocks in case of wind. Each day, ask students to measure the rainfall in the can with a centimeter ruler, then to empty the can. For the classroom, make a large poster of your rain can for students to update after rainfall measurement. When you have determined the total month's rainfall, compare it to the official figures. Were you close? Check an almanac to see previous years' precipitation levels. Was this year typical or unusual? Encourage students to find out the precipitation levels in other parts of the country and the world. Make a rain map to see the differences!