1. Earth’s Energy Budget

2. Modes of Energy Travel
Heat Energy can be transferred in three specific ways:
Conduction
Convection
Radiation

3. Heat Transfer
Conduction - transfers heat via direct molecular collision. An area of greater kinetic energy will transfer thermal energy to an area with lower kinetic energy. Conduction is the most common form of heat transfer and occurs via physical contact. Examples would be to place your hand against a window or place metal into an open flame. 

4. Heat Transfer
Convection – is heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it. As the immediate hot air rises, it pushes denser, colder air down.

5. Heat Transfer
Radiation – atoms emit electromagnetic waves. All materials radiate thermal energy based on their temperature. The hotter an object, the more it will radiate. The sun is a clear example of heat radiation that transfers heat across the solar system.

6. Solar Energy 70% absorbed 30% reflected
When radiant solar energy reaches the Earth, 2 different interactions occur:
Reflection – the radiation is reflected back into space unchanged
Absorption – the radiation is absorbed by the atmosphere of the Earth’s surface.
70% absorbed
30% reflected

7. Breakdown

8. Earth’s “Constant” Temperature
The Earth retains a relatively constant temperature.
To do this, it must lose as much energy back to space as it absorbs from the Sun.

9. Energy and Water
Most of the sun’s energy hits water on earth (earth is 70% water)
Interactions between the sun’s energy and water have a major influence on weather but it depends on what state the water is in
White snow and ice reflect the vast majority of solar energy in the water world.

10. Energy and Water
Liquid water reflects only about 7% (i.e. it absorbs about 93%!!!)
Therefore many weather systems are initiated from the energy that is absorbed by the oceans

11. Water in the Air Water exists in the air as a gas (water vapour)
When the air becomes saturated, condensation of the water vapour occurs (forms liquid water droplets)
The amount of water vapour in the air is measured by humidity
The incoming sun causes ~23% of liquid water to evaporate
Evaporation occurs from all bodies of water but mostly the oceans

12. Assignment
Using your notes, draw your own picture that shows the water cycle. Include the following terms:
Evaporation
Evapotranspiration
Condensation
Surface Runoff
Groundwater flow
Precipitation
Also add in the heat energy transfer you recorded in your notes.

13. Heating the Dry Land
Why is it that when you are at the beach, the sand can be scorching hot while the water is cool?
After all they are getting the same amount of solar radiation

14. Heating Dry Land
Water is cooler because it has a higher specific heat capacity – meaning that it can absorb much more heat than dry land
All sunlight that hits the sand or earth is absorbed in the top few cm making it 5 times as hot as water
All sunlight that hits water can be absorbed in layers much deeper thus making it cooler

15. Heating the Air The first step is conduction
Conduction heats the air by hot (energized) water and land molecules transferring their heat (energy) to the surrounding air
The air directly above the land or water then becomes a similar temperature to the temperature of the water or land

16. Heating the Air The second step is convection
As the lower layers of air warm, it expands becoming less dense
Since it is less dense and warm, it rises and cooler air takes the place closer to the ground
Other substances in the air such as CO2 and H2O (g) can absorb sunlight and can cause temperature in the air to fluctuate

17. Heating the Air Uneven heating of the air causes wind
When cold air is located near warm air it pushes it upwards and creates wind