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Temperature: Is It Hot Or Cold?
March 4th, 1998 DESCRIPTION: This lesson will demonstrate to students how to read thermometers, determining their rise or fall, recording temperatures for a two week period to understand sequence, and taking temperatures of various items for comprehension. GRADE LEVEL: Grade 2 GOAL: Students will understand temperature changes and will be able to read a thermometer. OBJECTIVES: (1) Demonstrate how the air around the earth gets heated and cooled by the sun. BACKGROUND: Air is sometimes hot. Sometimes it is cold. We measure the temperature of the air with a thermometer. The air that surrounds the earth is warmed by the sun. That's why the air is usually warmer during the day - when the sun is shining - than at night. In the summertime, the sun's rays shine more directly on the earth than during the winter. Also, on summer days the sun shines for more hours than it does on winter days. This makes summer temperatures higher than winter temperatures. CONCEPTS: Students will be able to: MATERIALS: thermometers mounted on plastic for student use PROCEDURES: Turn on the blow dryer and let children feel the air. (Caution: blow dryer may be hot!). Then turn on the fan and let it blow across the bowl of ice. Allow the children to feel this flow of air. Ask them to talk about the difference in how the air felt in each situation. Ask why they felt warm and cool air. Explain that today they are going to figure out how nature makes the air around the earth warm and cold, and how people measure the amount of heat or coldness in the air. 1. Ask students to tell where they believe the heat in the air comes from. Accept any and all ideas. Repeat question for the cool air. 2. Using the ball to represent the earth and the flashlight to be the sun, discuss with the students how the sun warms up the earth and how it then cools at night. Show how the earth tilts toward the sun in summer and receives more sun and how it tilts away from the sun in the winter and receives less sun. Students may take turns holding the ball and experimenting. 3. Using the larger teaching thermometer, show it to the class and explain its name and its function. Some dialog a teacher might use is: "Look at the thermometer. Do you see the red liquid in the round part at the bottom of the glass tube? As the air becomes warmer, the liquid grows bigger, or expands. It needs more room. Where can it go? (only up the tube) Then the air becomes cooler, the liquid cools off and contracts. It takes up less room. What happens? (It slides back down the tube) Lines on the thermometer show the temperature in degrees. Marked on one side of the thermometer is the Fahrenheit scale. This is the side we will be working with." 4. Have students all stand up and pretend to be liquid in the thermometer. Turn on the flashlight and shine it back and forth across the group as you tell them it is the sun. Ask them what will happen to them as the sun shines on them. They should say they will warm up and take up more space. Have them move slowly apart and take up more space in the room. They are "expanding". Turn off the flashlight because it is now nighttime. Ask them what will now happen to them. They should say "cool off" and "come back together". Have them move slowly back together as they take up less space and "contract". 5. Pass out student thermometers and have students measure temperature, with
modeling from the teacher, of (a) inside air - place thermometer on chalkboard tray for
five minutes (b) outside air - place thermometer on shady side of building for five
minutes (c) hot air - hold thermometer in front of your mouth and breath on the bulb
of the thermometer slowly for two minutes (d) icy air - stand thermometer in bowl of
ice cubes for five minutes. (The could be done as a class project with students
recording on a poster sized data chart. ASSESSMENT: Students will match temperatures to pictures of items related to temperatures.
Students will read thermometers and write down the temperatures. Students will draw
arrows to show which way the liquid will move in the thermometer under the shown
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