Rain Maker

Rain is very important to Earth. Rain supplies Earth with water, one of our most important resources. You know that rain is formed by warm air rising from Earth and cooling in the clouds. But have you ever seen this happen with your own eyes? Now you can. Try this simple activity to witness how raindrops form.

Before you begin the activity, visit the Cloud Boutique Web site at http://vortex.plymouth.edu/clouds.html and read about two types of rain clouds — nimbostratus and cumulonimbus clouds.

Then gather a clear quart jar with a lid, tap water, and 4 or 5 ice cubes. Follow the steps below.

1. Pour enough water into the jar to cover the bottom. Imagine the water is a lake or ocean.

2. Place the lid firmly over the opening of the jar. Think of the lid as a cumulonimbus cloud.

3. Put four or five ice cubes in the lid. The ice acts like the cooler air found high in Earth's atmosphere.

4. Wait ten to fifteen minutes. Predict what you think will happen. Write your answer on the lines below.

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5. What were the results? Write your answer on the lines below.

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   You should have noticed that water formed on the inside of the lid — just like rain forms in the clouds. The jar shows you some of the same processes that occur in nature. The warm air inside the jar rises, carrying moisture from the water at the bottom. On Earth, warm air carries moisture up from lakes, oceans, and other water sources. As the air in the jar reaches the top it cools because of the ice on the lid. In a similar way on Earth, the warm air cools the higher it rises in the atmosphere. When air cools, it drops the moisture it is holding. In the jar we see this moisture collect on the inside of the lid. On Earth, it's seen every time it rains. You made rain!

   Home Connection

   Go to the Understanding Lightning Web site at http://www.usatoday.com/weather/wlightn0.htm to learn more about lightning, such as what forms it can take and how you can keep yourself safe from it. Then make your own static electricity at home by following these steps:

   1. Have an adult charge a plastic comb by rubbing it with a dry cloth.
   2. Hold the comb under a stream of water.
   3. Watch the water “dance” when the comb is jiggled.