1. Lesson 1-6

2. Review
1) Troposphere: the atmospheric layer closest to the earth’s surface. The temperature and pressure decreases as you move away from earth. 2) Stratosphere: Contains the greatest amount of ozone! Ozone absorbs UV rays that could kill plants & animals and cause skin cancer in humans. 3) Mesosphere: Meteors burn up in this layer 4) Thermosphere: Meteors burn up in this layer. 5) Exosphere: Because the altitude is so high, atmospheric pressure and density are very low.

3. Review
Air pressure and Altitude: At higher altitudes, the air is less dense. Air pressure is greatest near earth’s surface.
Mountain climbers sometimes carry oxygen tanks because fewer oxygen molecules are in the air at higher altitudes.

4. Lesson 2 Reading Guide - KC
Energy Transfer in the Atmosphere
How does energy transfer from the Sun to Earth and the atmosphere?
Lesson 2 Reading Guide - KC

5. Energy from the Sun
Radiation is the transfer of energy by electromagnetic waves.
Radiation from the Sun consists of visible light, ultraviolet light (UV), and infrared radiation (IR).
The majority of sunlight is visible light that passes through the atmosphere to Earth’s surface, where it is converted to heat.
Lesson 2-1

6. Energy from the Sun (cont.)
(UV) light and infrared radiation (IR) cannot be seen by human eyes.
UV light is harmful to human skin and IR can be sensed as thermal energy or warmth. (think thermal vision!)
As energy from the Sun is absorbed by Earth, it is radiated back as IR.
Lesson 2-1

7. Visible light

8. UV light

9. Infared radiation.

10. Energy on Earth
As Sun’s radiation passes through the atmosphere, some of it is absorbed and some of it is reflected back into space.
reflect
Science Use to return light, heat, sound, etc., after it strikes a surface
Common Use to think quietly and calmly
Lesson 2-2

11. Energy on Earth (cont.)
Bright surfaces, especially clouds, reflect incoming radiation, and some is reflected at Earth’s surface (water or snow).
Lesson 2-2

12. Radiation Balance
The amount of radiation Earth receives from the Sun is the same as the amount Earth radiates into the atmosphere.
This radiation balance maintains an overall temperature on Earth.
Lesson 2-3

13. The Greenhouse Effect
Some of the gases in the atmosphere, called greenhouse gases, act like the glass of a greenhouse, allowing sunlight to pass through but preventing some of Earth’s IR energy from escaping.
Lesson 2-4

14. The Greenhouse Effect (cont.)
The gases that trap IR best are water vapor, carbon dioxide, and methane.
Lesson 2-4

15. Thermal Energy Transfer
Conduction occurs when the atmosphere touches Earth.
Conduction is the transfer of thermal energy by collisions between particles of matter.
Thermal energy always moves from an object with a higher temperature to an object with a lower temperature.
Lesson 2-5

16. Energy is transferred through conduction, convection, and radiation.
Lesson 2-5

17. Thermal Energy Transfer (cont.)
The transfer of thermal energy by the movement of matter from one place to another is called convection.
As molecules of air close to Earth’s surface are heated by conduction, they spread apart, becoming less dense.
Less dense air rises, transferring thermal energy to higher altitudes.
Lesson 2-5

18. Thermal Energy Transfer (cont.)
Latent heat is exchanged when water changes from one phase to another.
Water is the only substance that can exist as a solid, a liquid, and a gas at the temperature ranges on Earth.
Latent heat energy is transferred from Earth’s surface to the atmosphere.
Lesson 2-5