1. Lesson 2 Reading Guide - KC
Energy Transfers and Transformations
What is the law of conservation of energy?
How is energy transformed and transferred?
What are renewable and nonrenewable energy resources?
Lesson 2 Reading Guide - KC

2. Lesson 2 Reading Guide - Vocab
Energy Transfers and Transformations
work
open system
closed system
renewable energy resource
nonrenewable energy resource
law of conservation of energy
energy transfer
energy transformation
Lesson 2 Reading Guide - Vocab

3. Law of Conservation of Energy
The law of conservation of energy says that energy can be transformed from one form to another, but it cannot be created or destroyed.
In every energy transformation, some energy transfers to the environment.
1 and 2
Lesson 2-1

4. The radiant energy that shines out of the flashlight cannot be greater than the chemical energy stored in the battery.
answers to 3 and 4
Lesson 2-1

5. Law of Conservation of Energy (cont.)
When energy moves from one object to another without changing form, an energy transfer occurs.
The mechanical energy of a tennis racket changing the movement of the ball is an example of an energy transfer.
Come up with your own example of an energy transfer with your partners
Answer 5 and 6
Lesson 2-1

6. Law of Conservation of Energy (cont.)
When one form of energy is converted to another form of energy, an energy transformation occurs.
The conversion of chemical energy stored in a tennis player’s muscle changing to mechanical energy when she swings her arm is an example of an energy transformation.
Come up with your own example of an energy transformation with your partners.
Answer 7 and 8
Lesson 2-1

7. Law of Conservation of Energy (cont.)
Identify an energy transfer and an energy transformation that occurs when someone plays a guitar.
Answer 9 with partners.
Lesson 2-1

8. Law of Conservation of Energy (cont.)
Identify an energy transfer and an energy transformation that occurs when someone plays a guitar.
Answer: Chemical energy in the cells is transformed to mechanical energy in the fingers, then transferred to the guitar strings.
Electric energy from the amp is converted into sound energy when the chords are struck.
Check 9
Lesson 2-1

9. Law of Conservation of Energy (cont.)
To a scientist, work is the transfer of energy that occurs when a force makes an object move in the direction of the force.
Work is only being done while the force is acting on the object.
Any time there is an energy transformation or energy transfer, some energy is transformed into thermal energy.
Answers to 10 and 11
Lesson 2-1

10. Recall that to do work a force must be working on an object.
If a tennis player is holding a tennis ball before a serve, is she doing work on the ball?
Recall that to do work a force must be working on an object.
Come up with an example of work being done in your everyday life, with your partners.
Prompt for 12 and 13, answer both orally

11. Anytime there is an energy transformation or energy transfer, some energy is transformed into thermal energy.
Energy transformations are inefficient because not all the energy that is transformed to another form of energy is usable.
Answer 14 and 15

12. Lets go back to the flashlight
Lets go back to the flashlight. In a flashlight the transformation of chemical energy from the battery to radiant energy from the light bulb is inefficient. As the electric energy move through the circuit, some electric energy transforms to thermal energy. This makes the transformation inefficient, and this is why some bulbs are warm.
With your partners: Explain the above transformation and why its inefficient.
Answer 16

13. Systems
An open system is a system that exchanges matter or energy with the environment.
A closed system is a system that does not exchange matter or energy with the environment.
In reality, there are no closed systems because every physical system transfers some energy to or from its environment.
Answer 17, 18, and 19
Lesson 2-1

14. Renewable Energy Resources
A renewable energy resource is an energy resource that is replaced as fast as, or faster than, it is used.
Solar energy from the Sun is one type of renewable energy resource that can be converted into electric energy.
Answer 20. Discuss solar energy
Lesson 2-2

15. Renewable Energy Resources (cont.)
Wind moves the blades of a wind turbine to generate electric energy.
In hydroelectric plants, falling water is channeled through a turbine which transforms mechanical energy into electric energy.
Discuss other renewable resources
Lesson 2-2

16. Renewable Energy Resources (cont.)
Geothermal plants transfer thermal energy from the Earth to water, creating steam that turns turbines in electric generators. (click me)
Biomass includes wood, plants, manure, and garbage, all of which are sources of stored chemical energy that can be transformed to electric energy in energy plants.
Discuss other renewable resources
Lesson 2-2

17. Nonrenewable Energy Resources
Nonrenewable energy resources are energy resources that are available in limited amounts or that are used faster than they can be replaced in nature.
Fossil fuels include petroleum, natural gas, propane and coal.
In nuclear energy plants, uranium atoms are split apart in a process called nuclear fission.
Answer 21 Discuss non-renewable resources
Lesson 2-2

18. Most of the energy used in the United States comes from nonrenewable energy resources.
Discuss non-renewable resources
Lesson 2-2

19. What are renewable and nonrenewable energy resources?
Ask orally without looking!!
Lesson 2-2

20. What are renewable and nonrenewable energy resources?
Renewable: energy resource that is replaced as fast or fast than it is used
Nonrenewable: energy resource that is available in limited amounts or is used faster than can be replaced in nature
Answer
Lesson 2-2

21. Energy can be transferred and transformed, but it cannot be created or destroyed.
Systems are classified as open systems or closed systems based on their interactions with their environment.
Energy resources are classified as renewable or nonrenewable based on their abundance and availability.
Summarize lesson
Lesson 2 - VS

22. 1. Which term refers to the transfer of energy that occurs when a force makes an object move in the direction of the force?
A. conservation
B. work
C. closed system
D. open system
Answer 22
Lesson 2 – LR1

23. 2. A car’s engine is an example of which of these?
A. closed system
B. energy resource
C. geothermal energy
D. open system
Answer 23
Lesson 2 – LR2

24. NOW what do you think?
Do you agree or disagree?
1. In most systems, no energy is transferred to the environment.
2. Some forms of energy are replenished naturally.
Agree/Disagree statements 1 and 2
Lesson 2 - Now

25. 3. Which is an example of biomass?
A. open system
B. solar energy
C. nonrenewable energy resource
D. renewable energy resource
Answer 24
Lesson 2 – LR3