1. Energy: THERMODYNAMICS AND ENERGY CYCLE
Earth Science

2. The Laws of Energy
Law of Conservation
Laws of Thermodynamics

3. Law of Conservation
Law of Conservation = Energy is neither created nor destroyed in ordinary physical and chemical processes (non-nuclear)
It simply changes form and moves from place to place

4. Laws of Thermodynamics
Three Laws of Thermodynamics
First Law of Thermodynamics (Law of Conservation)
If energy is added to a system, one of two things must happen:
Heat is produced
Work must be done as a product
The conversion is not 100% efficient
Example: grass for cows, gas for cars, etc.

5. Laws of Thermodynamics
2. Second Law of Thermodynamics
Heat flows from a warmer object to a cooler object until equilibrium (balance) is reached
Example: An ice cube sitting on a hot sidewalk will melt into a little puddle
Once the puddle and sidewalk reach the same temperatures, the overall heat flow will be zero

6. Laws of Thermodynamics
3. Third Law of Thermodynamics
Absolute zero = absolute order
Absolute zero (-273C or -455F)
At absolute zero, atoms stop moving completely
No system can ever reach absolute zero under natural conditions

7. What does this have to do with Earth Science?
Convection currents drive plate tectonics
Convection currents also drive global air circulation patterns and the weather
Deep ocean currents
And more!

8. Essential Question
What is the relationship between the amount of energy and the temperature, volume, and speed?

9. Energy Cycle Energy in Atoms move faster and get farther apart
Volume decreases
Temperature increases
Density increases
Density decreases
Temperature decreases
Volume increases
Atoms move slower and get closer together
Pressure decreases in an open system increases in a closed
Energy out

10. ENERGY IN
Energy goes into the Earth’s system through Nuclear Energy in two ways:
Radioactive decay in the Earth’s core heats the interior.
Energy (heat) is transferred to the surface causing earthquakes and volcanic eruption

11. 2. Sunlight (visible light)
As photons (“pockets” of light energy) hit the Earth’s surface, they are absorbed and radiated back to the atmosphere as longer wavelengths (infrared energy)
This is how light is converted to heat and cause the convection in the atmosphere

12. Energy Cycle Energy in Atoms move faster and get farther apart
Volume decreases
Temperature increases
Density increases
Density decreases
Temperature decreases
Volume increases
Atoms move slower and get closer together
Pressure decreases in an open system increases in a closed
Energy out

13. Atoms
When energy is added, atoms become excited and begin to move faster and get farther apart

14. Energy Cycle Energy in Atoms move faster and get farther apart
Volume decreases
Temperature increases
Density increases
Density decreases
Temperature decreases
Volume increases
Atoms move slower and get closer together
Pressure decreases in an open system increases in a closed
Energy out

15. Temperature Temperature = the measure of how fast the atom are moving
The more energy put into the system, the faster the atoms move and the greater the temperature gets.

16. Energy Cycle Energy in Atoms move faster and get farther apart
Volume decreases
Temperature increases
Density increases
Density decreases
Temperature decreases
Volume increases
Atoms move slower and get closer together
Pressure decreases in an open system increases in a closed
Energy out

17. Density
Density = the measure of the number of atoms/molecules in a given space (volume)
The faster the atoms move and the farther apart they get, the less there will be in the same area.

18. Energy Cycle Energy in Atoms move faster and get farther apart
Volume decreases
Temperature increases
Density increases
Density decreases
Temperature decreases
Volume increases
Atoms move slower and get closer together
Pressure decreases in an open system increases in a closed
Energy out

19. Volume Increases Volume = space a set number of atoms/molecules occupy
The farther apart the atoms the more space they take up

20. Energy Cycle Energy in Atoms move faster and get farther apart
Volume decreases
Temperature increases
Density increases
Density decreases
Temperature decreases
Volume increases
Atoms move slower and get closer together
Pressure decreases in an open system increases in a closed
Energy out

21. Pressure
Pressure = the measure of the effect of atoms pushing on or impacting a given space
The more atoms pushing on a given space the higher the pressure

22. Pressure (continued…)
Pressure will decrease as long as the atoms are able to move freely (open system)
If the atoms are contained, the pressure will increase as the atoms move faster and have more impacts per unit of time (closed system)
Think of a tea kettle vs. a pot of boiling water
Tea kettle = higher pressure
Pot = lower pressure

23. Energy Cycle Energy in Atoms move faster and get farther apart
Volume decreases
Temperature increases
Density increases
Density decreases
Temperature decreases
Volume increases
Atoms move slower and get closer together
Pressure decreases in an open system increases in a closed
Energy out

24. Energy Out
As the energized atoms come into contact (conduction) with less energized atoms, they lose some of their energy to make the other atoms the same temperature
As energy is lost, the atoms slow down and get closer together
Temperature decreases as the atoms slow down
Density increases and volume decreases as the atoms move closer together

25. Equilibrium and Homeostasis
Nature wants everything to be equal and balanced
What happens when hot water and cold water are mixed?
The energy is spread evenly until the temperature is the same throughout.

26. Energy Cycle and Earth’s Systems
Convection currents in the mantle drive plate tectonics
Convection currents that form in the atmosphere drive weather patterns
Ocean currents

27. Energy Cycle Energy in Atoms move faster and get farther apart
Volume decreases
Temperature increases
Density increases
Density decreases
Temperature decreases
Volume increases
Atoms move slower and get closer together
Pressure decreases in an open system increases in a closed
Energy out

28. CRITICAL THINKING QUESTION
What are convection currents? (Hint: currents are movements of water. Think about the definition of convection. What happens to water when it is heated? What happens to water when it is cooled?