1. Chapter 2 Weather Factors
7th Grade Science

2. Section 1: Energy in Earth’s Atmosphere

3. Objectives:
State in what form energy travels form the sun to Earth.
Explain what happens to the sun’s energy in the atmosphere at Earth’s surface.

4. The movement of heat in the atmosphere causes temperature to change, winds to blow, and rain to fall.

5. Nearly all the energy in Earth’s atmosphere comes from the sun.
This energy travels to Earth as electromagnetic waves, a form of energy that can move through the vacuum of space.

6. Radiation is the direct transfer of energy by electromagnetic waves.
Most of the energy form the sun travels to Earth in the form of visible light and infrared radiation. A small amount arrives as ultraviolet radiation.

7. Visible light includes all of the colors that you see in a rainbow.
Infrared radiation is electromagnetic energy that can be felt as heat.
Ultraviolet radiation is electromagnetic energy that can cause sunburns, skin cancer, and eye damage.

8. Some sunlight is absorbed or reflected by the atmosphere before it can reach the surface. The rest passes through the atmosphere to the surface.

9. Dust particles and gases in the atmosphere reflect light in all directions, a process called scattering.

10. When Earth’s surface is heated, it radiates most of the energy back into the atmosphere as infrared radiation.

12. The process by which gases hold heat in the air is called the greenhouse effect.

14. Click below to watch a BrainPop on the Greenhouse Effect.

15. Section 2: Heat Transfer

16. Objectives:
Describe how temperature is measured.
Identify three ways in which heat is transferred.
Explain how heat is transferred in the troposphere.

17. Heat transfers through our environment all of the time
Heat transfers through our environment all of the time. Things are always getting warmer or cooler.

18. Temperature is the average amount of energy of motion of each particle of a substance.

19. Thermal energy is the total energy of motion in the particles of a substance.

20. Air temperature is usually measured with a thermometer.
A thermometer is an instrument used to measure temperature.

21. Heat is the transfer of thermal energy from a hotter object to a cooler one.
Heat is transferred in three ways…

22. 3 Types of Heat Transfer

23. 1. Radiation - the transfer of heat by electromagnetic waves

24. Examples of Radiation
* Sun warming Earth
* Camp fire
* Microwave oven
* Light Bulb

25. 2. Conduction - the transfer of heat from one substance to another substance that it is touching

26. Examples of Conduction
* Ironing a shirt
* Feet on hot sand
* Spoon in hot liquid getting warm
* Stove making a pot get hot

27. 3. Convection - the transfer of heat by the movement of a fluid(liquids and gases)

28. Examples of Convection
* Warm water rising to top in pool
* Stove heating up and warming room
* Earth’s mantle
* Lava Lamp

29. Radiation, conduction, and convection work together to heat the troposphere.

30. Within the troposphere, heat is transferred mostly by convection.
The upward movement of warm air and the downward movement of cool air form convection currents.

31. Check out this Heat Transfer Website