All energy from the sun that reaches Earth is converted to thermal energy or heat. The amount of heat absorbed at the surface varies by location and time due to factors like the sun's angle, cloud cover, Earth's distance from the sun, and greenhouse gases trapping heat in the atmosphere. This trapped heat maintains Earth's temperature through the greenhouse effect, resembling the way a greenhouse warms an environment for plants. Different surfaces like land, water, and air heat up differently via radiation, convection, and conduction.

1. 9 th Grade Chapter 2 Lesson 3 Pgs. 32-38 For Student Use Only

2. Heat and Atmosphere All energy in the atmosphere comes from the sun. All energy from the sun (except what is reflected back) is converted into Thermal Energy! Thermal Energy= heat The amount of heat absorbed on the surface of the Earth varies from place to place and time to time. There is a balance between heat collected and heat reflected

3. Heat and Atmosphere Insolation: Insolation- incoming Solar Energy/Radiation Measured in watts per square inch Not all energy reaches the earth, some is absorbed by the gases in the atmosphere Cloudy skies can reduce insolation The length of day affects insolation

4. Heat and Atmosphere Insolation: The Angle of Insolation (or angle of sun’s rays): Winter: the sun is lower and the sun’s rays have to cover a larger area Summer: the sun is higher in the sky and the rays are more concentrated Earth’s distance from the sun: This affects insolation because of closeness or distance from sun Perihelion- closest point (more insolation) Aphelion- farthest point from the sun (less insolation)

5. Heat and Atmosphere Energy The energy that is not reflected into space becomes part of the earth’s energy budget. Energy Budget- The amount of energy available to heat the earth’s land, water and air This energy circulates between land, air and water before it is reflected back to space. Some energy goes back to space as it radiates from the earth into the atmosphere and out again.

6. Heat and Atmosphere Energy: Although some energy is radiated back to space, most infrared energy (heat energy) from the sun and Earth’s surface is trapped inside the Earth This trapping of energy in the Earth’s atmosphere is referred to the Greenhouse Effect . This “trapping” maintains Earth’s temperature.

7. Heat and Atmosphere Greenhouse Effect: This trapping of heat resembles what a greenhouse does for gardeners. Carbon Dioxide and Water Vapor in atmosphere let UV waves in but stop infrared (heat) waves from leaving This also causes the warmest part of the day to be well after noon (around 3pm over land and 5pm over sea).

8. Heat and Atmosphere Insolation and Heating Water warms slowly and holds heat longer Almost ¾ of Earth is covered with water Water and land heat differently

9. Heat and Atmosphere Earth’s Atmosphere Earth is made of many different materials that heat differently. Land, Water, and Air heat differently.

10. Heat and Atmosphere Types of Heating Radiation- heat travels in electromagnetic waves. This requires NO medium to travel through Convection- Heat moving through air (or other fluid) as warm air rises and cool air sinks Conduction- Direct contact between 2 objects passes heat

11. Heat and Atmosphere Heating and Wind Winds are caused by a horizontal movement of air. Air moves because as warm air rises cooler air rushes in to take its place (convection currents)

12. Heat and Atmosphere Heating of Air Adiabatic Heating- the temperature of a gas increases as the gas is compressed Adiabatic Cooling- the temperature of a gas lowers as it expands NOTE: As a body of air rises its temperature drops (convection currents)