How do science concepts apply to your world? Here are some questions you'll be able to answer after you read this chapter.

• What would Earth be like without an atmosphere?
• What causes the seasons?
• Why is there often a cool breeze at the beach?
• How can the air cause a bad hair day?
• What causes thunder and lightning?
• How reliable are weather forecasts?
• How do human activities affect climate?
• What happens when a hurricane reaches land?

Why Do Cold Surfaces Become Wet?

Procedure

1. Fill a metal pitcher halfway with warm water. Use paper towels to dry off the outside of the pitcher. With a thermometer, measure the temperature of the air in the classroom and the temperature of the water in the pitcher. Record these temperatures. CAUTION: Wipe up any spilled water right away to avoid slips and falls.
2. Fill a 100-mL beaker with crushed ice. Then, pour the ice into the pitcher and stir the ice with a long-handled spoon.
3. Repeat Step 2 until water begins to appear on the outside of the pitcher. When this occurs, measure and record the temperature of the water in the pitcher.

Think About It

1. Analyzing Data   Compare the temperature at which drops of water appeared on the outside of the pitcher to the temperature of the air in the classroom.
2. Formulating Hypotheses   How do you think the water appeared on the outside surface of the pitcher?