Make It Rain!

Can you make it rain indoors? Learn about the water cycle with this simple experiment!

Vocabulary

1. Condensation–
   (noun) a chemical reaction involving union between molecules often with elimination of a simple molecule (as water) to form a new more complex compound of often greater molecular weight; the process by which a gas cools and becomes a liquid
2. Water Cycle–
   (noun) the series of conditions through which water naturally passes from water vapor in the air to being deposited (as by rain or snow) on earth’s surface and finally back into the air especially as a result of evaporation
3. Precipitation–
   (noun) water or the amount of water that falls to the earth as hail, mist, rain, sleet, or snow
4. Water Vapor–
   (noun) water in a gaseous form especially when below boiling temperature and spread through the atmosphere
5. Atmosphere–
   (noun) a mass of gases surrounding a planet or star

Materials

• Glass mayonnaise or canning jar
• Plate
• Ice cube
• Hot water

Safety Note: Extremely hot water could scald the skin.

Activity

1. Pour about two inches of very hot water into a glass jar.
2. Cover the jar with a plate and wait a few minutes before you start the next step.
3. Place your ice cubes on the plate and observe the reaction.

What happens?

The cold plate causes the moisture in the warm air, which is inside the jar, to condense and form water droplets. This is the same thing that happens in the atmosphere. Warm, moist air rises and meets colder air high in the atmosphere. The water vapor condenses and forms precipitation that falls to the ground.

Now what?

Look for other examples of condensation, such as water drops forming on the side of a cold drink can. Use what you have learned about condensation to explain your observations.

Explanation

In nature, heat from the sun allows tiny water molecules to evaporate (change from liquid to gas) and rise up into the sky. As the warm, water-filled air rises, it cools and a cloud of water vapor forms. Cold air can’t hold as much water as warm air, so some of the water condenses and falls back to the earth as rain, ice or snow.