Presentation on theme: "Question of the Day….1-13-14 1. Does the absorption of sunlight lower or increase Earth’s temperature? 2. How does solar energy reach Earth? 3. Why should."— Presentation transcript:
Question of the Day….1-13-14 1. Does the absorption of sunlight lower or increase Earth’s temperature? 2. How does solar energy reach Earth? 3. Why should you wear dark clothing in the winter, and light clothing in the summer, if you work outdoors?
How is Earth’s Surface heated?
Modeling the Absorption of Light… Hypothesize: Which color will be the hottest? 1. Place an aluminum pan under a light whose light is pointed downward. 2. Place two different colors of construction paper into the pan. One color should be dark, the other a light color. 3. Insert a thermometer on top of each piece of paper. Record the temperature of each. 4. Let the papers sit under the lamp for five minutes. How does the temperature change? Why is one temperature higher than the other?
Key Terms Radiant Energy: energy given off by the Sun that can travel through empty space. Radiation: movement of the Sun’s energy through empty space. Absorb: To take in Reflect: To bounce back
What kind of energy is sunlight? Have you ever walked barefoot across a sidewalk on a sunny day? Did your foot feel the warmth of the hot pavement? The sidewalk was heated as it absorbed the Sun’s energy. Sunlight is an example of radiant energy. Your foot burned due to Conduction.
Radiation When energy is absorbed by a surface, the surface becomes heated. This is why you are able to feel the sun’s rays on your skin when you stand in the sun. Your skin absorbs the radiation, causing your skin’s molecules to move a little faster. RADIATION IS THE TRANSFER OF ENERGY AS ELECTROMAGNETIC WAVES!
Absorption of Energy Dark surfaces absorb or take in light. When sunlight is absorbed, it is usually changed into heat. Dark colored objects become hotter than light colored objects. Light colored objects reflect, or bounce back sunlight. They are cooler.
Hypothesize… Which do you think will absorb more heat from the sun, land or water? Land
Decide whether each item listed will absorb or reflect radiant energy. Write A for absorb or R for reflect in the space provided. 1.cream-colored sweater 2.black suit 3.concrete sidewalk 4.white shirt 5.tar-covered street 6.dark green tent
Energy from the Sun… Only a small part of the Sun’s energy reaches Earth. Some of the Sun’s energy is absorbed by the atmosphere. Clouds, dust particles and water droplets in the atmosphere reflect some of the Sun’s energy. The energy that is reflected goes back into space.
Energy from the Sun… Some of the energy that passes through Earth’s atmosphere is absorbed or taken in by Earth’s surface. This energy is changed into heat. As a result, Earth becomes warmer. **Create a graphic organizer showing how Earth’s Surface is heated. Use the diagram on the next slide.
Do you Remember? 1. Light is a type of ________. 2. The Sun’s energy reaches Earth by __________. 3. When light is __________, it turns into heat. 4. Clouds, ________ _________ and water droplets can reflect, or absorb radiant energy. 5. Predict: If there were no wind, would it be cooler on a sunny day or a cloudy day?