1. 10.2 Thermal Energy Transfer p. 375 - 387
The Earth’s surface, especially water, has a HUGE influence on our climate and weather.

2. Planet Water 70% of Earth’s surface is covered with water
Water plays a major role in the absorption and distribution of thermal energy, influencing both weather and climate: the great
moderator

3. Specific Heat Capacity
The amount of heat (J) required to raise the temperature of 1 g of a substance by 1o C

4. Large bodies of water MODERATE temperature and climate.
It takes a lot of solar radiation to heat water, so water is a heat sink.
It absorbs a great deal of solar radiation, keeping the region cooler during the day, and it slowly reradiates the heat at night

5. Areas around large bodies of water (Great Lakes, oceans) do not experience extreme weather changes like areas that don’t have large bodies of water i.e continent interiors (think Saskatchewan and Alberta), and deserts.

6. Specific heat capacity is a constant and is represented by “c”
SUBSTANCE
c (J /g oC)
Pure water
4.19
Steam
2.02
Ice
2.00
Sea water
3.89
Moist air
1.15
Dry air
1.00
Pg. 375

7. Formula Q = mcΔT c = specific heat capacity J/goC
ΔT = change in temperature oC
m = mass g
Q = amount of heat J
If data are given in initial (T1) and final (T2) temperatures instead of change in temperature, calculate ΔT using ΔT = T2 – T1

8. Practice Problems Model Problems A and B, pg. 376
Do Practice Problems #1 – 9 pg. 377

9. THE EFFECTS OF SPECIFIC HEAT CAPACITY ON THE EARTH’S WEATHER AND CLIMATE
a) The Earth’s land or water surface heats up as it absorbs solar radiation.
b) This thermal energy is transferred by conduction to surrounding cooler air or water causing convection currents in air and water

10. Convection (transfer of thermal energy in fluids – liquids or gases)
Convection currents – air circulates and distributes heat (remember warm air is less dense, rises, cooler air descends and takes its place close to the ground, it heats up…etc.

11. How does all this affect weather and climate?
Different specific heat capacities of the Earth’s different surfaces (sand, water, forests, etc) affect how much they heat up the air and water around them.

12. Huge air and ocean currents distribute heat in amazing patterns around the earth, greatly affecting the climate and weather of many regions.

13. Heat of Fusion, Heat of Vaporization: Phase Changes of Water
Why is the ice and water absorbing energy with no change in temperature?

14. How does this affect our weather and climate?
The Earth’s water absorbs a lot of heat from the surroundings when condensing, and it releases a lot of heat when it is evaporating.

15. If you think of all the water that is condensing or evaporating all over the lakes, ponds, streams, oceans and clouds that’s a lot of heating and cooling!

16. Definitions
Heat of vaporization (Hvap) is the amount of thermal energy required to convert one mole of a substance from a liquid to a gas (evaportate it)
Heat of fusion (Hfus) is the amount of thermal energy required to convert one mole of a substance from a solid to a liquid (melt it)

17. Calculations Q amount of heat energy J (joules)
Energy required for melting Energy required for vaporizing
Q = nHfus Q = nHvap
Q amount of heat energy J (joules)
n number of moles (no units)
Hfus heat of fusion J/mol
Hvap heat of vaporization J/mol

18. Model Problems pg. 382 – 383
Practice Problems 10 – 18 pg. 383

19. Hydrologic (Water) Cycle
The hydrologic cycle distributes water by evaporation, condensation, and precipitation.
It transports thermal energy as well. When water condenses, thermal energy is released, when water evaporates it absorbs thermal energy affecting weather and climate

20. Assignment Specific Heat Practice problems # 1-9 pg. 377
Heat of fusion and vaporization problems #10-18 pg. 383
Questions: Pg. 387 #1, pg #11, 12 (question # 13 gives you hints), 14, 16