SCIENCE CONCEPT:

Heat warms the air around the earth, causing changes in atmospheric conditions: temperature, density, and pressure.

STUDENT OBJECTIVE:

The student will discover that warm air rises.

OVERVIEW:

The student will use two small bags, a wooden balance, and a heat source to discover that rising warm air can make an object rise.

TEACHER TEXT:

PREPARATION TIME: 15 minutes.

TEACHER PREP: Gather materials.

LESSON TIME: 20 minutes.

WORDS TO KNOW:

• expand
• rise
• balance

MATERIALS NEEDED:

• two, small paper bags
• two pieces of thread, approx. 10" long
• tape
• wooden balance
• candle
• match

STEPS TO FOLLOW:

1. Open the bags. Use the tape to attach one end of string to each bag. Tie a loop on the free end of each string and hang from the ends of the balance rod.

2. Move the bags along the ends of the rod until they are exactly balanced.

3. Light the candle and carefully heat the air below one of the bags.

4. Wait a few minutes. Observe. (The bag above the candle rises.)

WHY?

As air is warmed, the particles (molecules) it is made up of spread out. This makes the air lighter (less dense), and it rises. The rising warm air above the candle filled the bag and caused it to rise, also.

ASSESSMENT: Can the student communicate what they observed?

4....The student is able to communicate that the hair dryer warmed the air inside the tissue balloon making the air lighter. The lighter air rose and filled the balloon causing it to rise, also.

3....The student is able to communicate that the warm air caused the bag to rise.

2....The student is able to communicate that the candle made the bag rise.

1....The student is able to communicate that the bag rose.