1. Chapter 8 Note-taking Guide
Forms of energy
Energy transfers and transformations
Particles in Motion

2. Define energy, and provide examples of its influences
The ability to cause change.
Climate
Energy drives storms.
Economy
Fuels provide the energy needed to power vehicles and transport goods.
Politics
Politicians discuss policies related to new energy resources.

3. Describe potential energy
Stored energy due to the interaction between objects or particles
Gravitational
Depends on an object’s mass and height above Earth’s surface
Chemical
Energy stored in and released from the bonds between atoms.
Nuclear
Energy stored in and released from the nucleus of an atom.

4. Differentiate potential energy and kinetic energy.
Stored energy due to the interaction between objects or particles
Kinetic energy
Energy due to motion

5. Relate kinetic energy to mass and speed of objects.
No speed
No kinetic energy
Greater mass
Greater kinetic energy
Greater speed

6. Explain why electric energy is a form of kinetic energy.
Electric energy is the motion of flowing electrons.

7. Model a system and an environment
Model a system and an environment. Define each term, and label the part of the diagram that represents each term.
System
A collection of interacting objects, parts, or ideas that work together as a whole.
Environment
Everything that is not in the system.

8. Compare and contrast mechanical energy and thermal energy.
Both
Thermal Energy
The sum of the potential energy and the kinetic energy in a system
The sum of potential energy and kinetic energy
The sum of the energy of the particles that make up an object

9. Wave: A disturbance. does not move matter. does move
energy from one place to another.
moves in which direction?
outward.

10. Identify two types of energy carried by waves.
Type of Energy
Carried By
Moves Through
Sound energy
sound waves
matter
Radiant energy
electromagnetic waves
matter and space without matter

11. Connect It Relate every form of energy mentioned in Lesson 1 to at least one other energy form.
Three types of potential energy are gravitational potential, chemical and nuclear energy.
Electric energy is a form of kinetic energy.
Both mechanical and thermal energy represent the combinations of potential and kinetic energy.
Both sound and radiant energy are carried by waves.

12. NGSSS Check What is the law of conservation of energy?
The law of conservation of energy says that energy transformations conserve energy and neither create nor destroy it.

13. Express the law of conservation of energy in a diagram
can be transformed from one form to another.
cannot be created or destroyed.

14. Apply the law of conservation of energy to energy transformations that occur in a flashlight.
Chemical energy from the battery
electric energy moving through the contact strip to the bulb
radiant energy + thermal energy in the bulb
transformed to
transformed to

15. NGSSS Check Identify an energy transfer and an energy transformation that occurs when someone plays a guitar.
Chemical energy is a person’s cells is transformed to mechanical energy in the fingers
Mechanical energy is then transferred to the guitar strings
Mechanical energy from the guitar strings is transformed into sound energy and elastic energy

16. Contrast energy transfer with energy transformation
Energy moves without changing form.
Energy changes form as it moves.

17. Identify three criteria required for an energy transfer to be considered an occurrence of work.
A force makes an object move.
The motion is in the direction of the force.
The object moves while the force is acting on it.

18. Explain what makes an energy transformation inefficient.
Not all of the energy is transformed to a usable form of energy.

19. Distinguish an open system from a closed system.
Definition:
A system that exchanges matter or energy with the environment.
Example:
A car engine.
Explanation:
Thermal energy and sound energy are released into the environment.
Definition:
A system that does not exchange matter or energy with the environment.
Example:
None exist.
Explanation:
Scientists use the idea to study and model the movement of energy.

20. Categorize resources that people transform into electric energy.
Category
Definition
Types
Renewable energy resource
An energy resource that is replaced as fast as, or faster than, it is used
Solar
Wind
Hydroelectric
Geothermal
Biomass
Nonrenewable energy resource
An energy resource that is available in limited amounts, or that is used faster than is can be replaced in nature
Fossil fuels
Nuclear energy

21. Synthesize It Explain two reasons it is wise to use energy-efficient electric appliances.
Some energy is already lost in every transformation; more energy is put into a device than the work we get out of the device.
Also, a majority of our electricity comes from nonrenewable resources, so it is smart to use it sparingly and to make it last.

22. Record 3 major points of the kinetic theory.
All matter is made of particles (atoms).
Particles are in constant, random motion.
Particles constantly collide with each other and the walls of their container.

23. Relate temperature to thermal expansion.
When
temperature
Increases, the
average
kinetic energy of
particles
increases
Thermal expansion
occurs when particles
collide more often and
push each other farther
apart

24. Differentiate temperature and heat
Differentiate temperature and heat. Circle the word in each definition that most distinguishes the meaning of the term.
Temperature
The measure of the average kinetic energy of the particles in a material
Heat
The movement of thermal energy from a region of higher temperature to a region of lower temperature

25. Identify and describe the condition under which two materials in contact would each have temperature but no heat.
The condition is called thermal equilibrium. If the temperatures of two materials are the same, kinetic energy does not move (as heat) from one to another.

26. Describe 3 ways in which thermal energy is transferred.
Method
Description
Conduction
The transfer of thermal energy due to collisions between particles in matter
Radiation
The transfer of thermal energy by electromagnetic waves
Convection
The transfer of thermal energy by the movement of the particles from one part of a material to another

27. Characterize the relationship between heat and typical changes of state.
Add enough thermal energy to a solid…
It melts, or becomes
a liquid
Remove enough thermal energy from a liquid…
It freezes, or becomes
a solid
Vaporization, or the
change from liquid to
gas, occurs.
Add enough thermal energy to a liquid…
Condensation, or the
change from gas to
liquid, occurs.
Remove enough thermal energy from a gas…

28. Differentiate types of vaporization.
Two Types of Vaporization
Boiling occurs within liquid
Evaporation occurs at surface
Identify which of the processes above requires an addition of thermal energy.
Both

29. Distinguish sublimation from deposition
Distinguish sublimation from deposition. Circle the process that represents an increase in thermal energy.
Sublimation
Deposition
Solid changes to gas without going through a liquid state.
Gas changes to solid without going through a liquid state.

30. Contrast the ability of materials to transfer thermal energy.
Energy transfer:
Quick
Reason:
Electrons are free to move
Thermal
conductor
Energy transfer:
Slow
Reason:
Electrons are held tightly in place
Thermal
insulator

31. Connect It Describe the thermal energy transfers between particles that occur when you overheat some soup for lunch, then drop an ice cube in it to cool it off.
Heat transfers from the stove burner to the pan holding the soup by conduction.
Heat transfers within the soup by convection, causing it to boil.
After adding the ice cube, heat transfers from the soup to the ice, causing the ice to melt and become water.
The soup continues to cool and the water (formerly ice) continues to heat up until both liquids are at thermal equilibrium.

32. Summarize It Reread the Think About It question and the lesson Key Concepts. Summarize what you have learned by converting two of the Key Concept questions from each lesson into factual answers.
Lesson 1
Potential energy and kinetic energy differ in that objects (and particles) with kinetic energy are in motion
Kinetic energy and thermal energy are similar in that they both represent the sum of potential and kinetic energy.

33. Summarize It Reread the Think About It question and the lesson Key Concepts. Summarize what you have learned by converting two of the Key Concept questions from each lesson into factual answers.
Lesson 2
The law of conservation of energy says that energy can be transformed from one form to another, but it cannot be created or destroyed.
Renewable energy resources can be replaced as quickly as they are used. Nonrenewable energy resources are used faster than they can ever be replaced.

34. Summarize It Reread the Think About It question and the lesson Key Concepts. Summarize what you have learned by converting two of the Key Concept questions from each lesson into factual answers.
Lesson 3
Kinetic theory says that all matter is made up of particles that are in constant, random motion and constantly collide with each other and the walls of their container.
Thermal energy is transferred through conduction, convection and radiation.