Lesson 3: The Wind

Explain to your child that air is heavy. We call the weight of the air pushing down on the earth air pressure. Air pressure changes if you go up or down. If your child has ever been on a plane, her ears may have hurt. This is because as we go higher there is less air above us and it is not as heavy. Our ears are very sensitive to pressure, so they may hurt or feel uncomfortable as air pressure changes. Scientists use a tool called a barometer to measure air pressure.

NOTE: Page 18 in the book also explains air pressure. Optionally, share this page with your child. If you have the time and materials, you could try the demonstration yourself!

Tell your child that today she will be looking at two different instruments that can help her measure wind. Ask her what a weather vane indicates (the direction of the wind), and what a barometer measures (air pressure).

Reminder

Explain to your child that a weather vane is a useful tool for forecasting weather because certain winds tend to bring good weather, while others often bring rain or colder temperatures. A weather vane gives clues about what to expect: winds from the west are likely to indicate fair weather, while winds from the east are likely to signal that rain or snow is coming.

For this activity, your child will create her own weather vane. You and your child should look over the "Make Your Own Weather Vane Page" (Option 1) and the wind vane on p. 47 of the book (Option 2) and decide which vane she should make based on available materials. Note that the wind vane in the book must be mounted on a fence post or something similar.

Your child should save the weather vane for the final project.

Your child should follow the directions on the "Make Your Own Weather Vane" page. Assist her as needed.

Your child should follow the directions on p. 47 of The Kids' Book of Weather Forecasting. Assist her as needed.

Explain to your child that a barometer helps meteorologists predict changes in the weather. When air becomes warm, it gets lighter and rises. This means that there is less air pressing down and that the air pressure is falling. Often low pressure brings stormy weather. As air cools, it becomes heavy and sinks. This rise in the air pressure means clear skies. Share the green graphic on p. 24 of the book with your child — it provides an easy way for her to remember what changes in pressure usually mean.

For this activity, your child will follow the instructions on the "Building a Barometer" page to create her own barometer. Be sure to save your child's barometer for the final project.

NOTE: For best results, choose a balloon that the about 12" in diameter when inflated a straight straw cut to about 14-17 cm. in length, and a standard 14 or 15 oz. metal can for the barometer.

Take a walk outside with your child on a windy day. Encourage her to stand still at different parts in your walk and feel the wind. In her journal, she can describe how the wind feels. Let her watch the leaves and branches as they move in the wind. She can toss a leaf into the wind and see what happens.