1. 14.3 – NOTES Thermal Properties

2. B.2 Earth’s Energy Balance
Average temperature is 15 C/ 59 F
Properties determine how much thermal energy our planet can hold near its surface
30% of radiation never reaches the surface, but is reflected back to space
70% of radiation reaches the surface
2/3 is absorbed, warming the atmosphere, oceans and continents
1/3 powers hydrologic (water) cycle

4. Greenhouse gases
Any gas that absorbs infrared radiation
CO2, H2O, CH4, N2O, halogenated hydrocarbons, CFCs
Greenhouse effect
Trapping and returning of IR by carbon dioxide, water, and other atmospheric molecules

6. The balance of water and CO2 keep our temperature above the estimated -18 C (0F)
Venus has greenhouse to the extreme
Venus is 96% CO2 in its atmosphere, so it absorbs a lot more IR, which raises the temperature to 450 C

8. Climate connections
Interaction of solar radiation and atmosphere also create weather
Warm air expands, decreasing density and causing warm air to rise
Weather is causes by movement of warm and cold air mass
Weather is what is happening at a specific time and location
Climate- average weather conditions in an area

10. Answer the following questions:
B.3 Solar Radiation
- Why is human exposure to UV radiation potentially more harmful than exposure to IR radiation?
1. UV has a shorter wavelength and more energy than IR.
2. UV has enough energy to break chemical bonds and harm living things.
- Describe two essential roles played by visible solar radiation.
1. Visible light activates photoreceptors in eyes allowing us to see
2. Provides energy for photosynthesis
- Explain why dry, arid regions in the US such as New Mexico or Arizona experience wider air-temperature fluctuations from night to day than do states with more humid conditions, such as Florida.
1. Water molecules in air trap and reradiate IR even at night, keeping air temperatures about the same. Humid climates have more H2O in the air.

11. B.4 Thermal Properties at Earth’s Surface
Reflectivity
The proportion of radiation that is reflected does not raise the object’s temperatures
Light colors stay cooler
Snow reflects 95% of light
Lawns reflect 15-30%, asphalt none

12. Specific heat capacity
See page 249
Quantity of thermal energy needed to raise 1 g by 1C
Also storage capacity for heat
Higher specific heat capacity = store more heat

15. Metals have low specific heats
Water is unique
Very high specific heat (4.18 j/g°C)
Can absorb a lot of heat without
changing the temperature

16. Every material has a characteristics reflectivity and heat capacity, which together
Determine how much and how fast the material warms