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Chapter Introduction
Lesson 1 Forms of Energy
Lesson 2 Energy Transfers and Transformations
Lesson 3 Particles in Motion
Chapter Wrap-Up
What is the difference between energy transfers and energy transformations?
What do you think?
Before you begin, decide if you agree or disagree with each of these statements. As you view this presentation, see if you change your mind about any of the statements.
1. An object sitting on a high shelf has no energy.
2. There are many forms of energy.
3. In most systems, no energy is transferred to the environment.
Do you agree or disagree?
4. Some forms of energy are replenished naturally.
5. Only particles that make up moving objects are in motion.
6. Thermal energy can be transferred in several ways.
Do you agree or disagree?
Lesson 1 Reading Guide - KC
• How do potential energy and kinetic energy differ?
• How are mechanical energy and thermal energy similar?
• What two forms of energy are carried by waves?
Forms of Energy
Lesson 1 Reading Guide - Vocab
• energy
• potential energy
• chemical energy
• nuclear energy
• kinetic energy
• electric energy
Forms of Energy
• mechanical energy
• thermal energy
• wave
• sound energy
• radiant energy
Lesson 1-1
• Energy influences everything in your life, including the climate, the economy, and your body.
• Scientists define energy as the ability to cause change.
Energy
Lesson 1-2
• Potential energy is stored energy due to the interaction between objects or particles.
• Objects have potential energy if they have the potential to cause change.
Potential Energy
Lesson 1-2
Objects have gravitational potential energy if they have mass and height above Earth’s surface.
Lesson 1-2
• Chemical energy is the energy stored in and released from the bonds between atoms.
• Your body breaks chemical bonds in foods and coverts the released energy into other forms of energy that your body can use.
Potential Energy (cont.)
Lesson 1-2
• The energy stored in and released from the nucleus of an atom is called nuclear energy.
• The Sun’s energy is released through the process of nuclear fusion, during which the nuclei of atoms join together and release large amounts of energy.
Potential Energy (cont.)
Lesson 1-3
• Kinetic energy is energy due to motion.
• An object’s kinetic energy is related to the mass and the speed of the object.
• The energy in an electric current is electric energy.
Kinetic Energy
Lesson 1-3
Kinetic Energy (cont.)
How do potential energy and kinetic energy differ?
Lesson 1-4
The sum of the potential energy and the kinetic energy in a system is mechanical energy.
Combined Kinetic Energy and
Potential Energy
mechanical
from Greek mēchanē, means “machine”
Lesson 1-4
• An object’s thermal energy is the sum of the kinetic energy and the potential energy of the particles that make up the object.
• Thermal energy of an object increases when the potential energy, the kinetic energy, or both increase.
Combined Kinetic Energy and
Potential Energy (cont.)
Lesson 1-4
Combined Kinetic Energy and
Potential Energy (cont.)
Compare mechanical energy and thermal energy.
Lesson 1-4
• A wave is a disturbance that transfers energy from one place to another without transferring matter.
• Sound energy is carried by sound waves.
• The energy carried by electromagnetic waves is radiant energy.
Energy Carried by Waves
Lesson 1-4
Electromagnetic waves often are described by their wavelengths—the distance from one point on a wave to the nearest point just like it.
Lesson 1-4
Visible light is one form of radiant energy.
Lesson 1-4
Energy Carried by Waves (cont.)
What two forms of energy are carried by waves?
Lesson 1 - VS
• Objects can have potential energy (stored energy) and kinetic energy (energy due to movement).
• Mechanical energy is due to large-scale motions and interactions in a system. Thermal energy is due to atomic-scale motions and interactions in particles.
Lesson 1 - VS
• Two kinds of energy carried by waves are sound energy and radiant energy.
Lesson 1 – LR1
A. chemical energy
B. kinetic energy
C. mechanical energy
D. nuclear energy
Which term describes energy stored in and released from the bonds between atoms?
Lesson 1 – LR2
A. wave
B. wavelength
C. potential energy
D. thermal energy
Which refers to a disturbance that transfers energy from one place to another without transferring matter?
Lesson 1 – LR3
A. chemical energy
B. nuclear energy
C. potential energy
D. radiant energy
What type of energy provides the warmth from the Sun?
Lesson 1 - Now
1. An object sitting on a high shelf has no
energy.
2. There are many forms of energy.
Do you agree or disagree?
Lesson 2 Reading Guide - KC
• What is the law of conservation of energy?
• How is energy transformed and transferred?
• What are renewable and nonrenewable energy resources?
Energy Transfers and Transformations
Lesson 2 Reading Guide - Vocab
• law of conservation of energy
• energy transfer
• energy transformation
Energy Transfers and Transformations
• work
• open system
• closed system
• renewable energy resource
• nonrenewable energy resource
Lesson 2-1
The law of conservation of energy says that energy can be transformed from one form to another, but it cannot be created or destroyed.
Law of Conservation of Energy
Lesson 2-1
The law of conservation of energy indicates that the amount of radiant energy that shines out of the flashlight cannot be greater than the chemical energy stored in the battery.
Lesson 2-1
Law of Conservation of Energy (cont.)
What is the law of conservation of energy?
Lesson 2-1
• 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.
Law of Conservation of Energy (cont.)
Lesson 2-1
• 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.
Law of Conservation of Energy (cont.)
Lesson 2-1
Law of Conservation of Energy (cont.)
Identify an energy transfer and an energy transformation that occurs when someone plays a guitar.
Lesson 2-1
• 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.
Law of Conservation of Energy (cont.)
Lesson 2-1
• Because energy transformations are inefficient, some of the chemical energy transforms to thermal energy and sound energy that are released to the environment.
• An open system is a system that exchanges matter or energy with the environment.
Law of Conservation of Energy (cont.)
Lesson 2-1
• 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.
Law of Conservation of Energy (cont.)
Lesson 2-1
Law of Conservation of Energy (cont.)
system
from Greek systema, means “whole made of several parts”
Lesson 2-2
• 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.
Energy Transformations and
Electric Energy
Lesson 2-2
• 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.
Energy Transformations and
Electric Energy (cont.)
Lesson 2-2
• Geothermal plants transfer thermal energy from the Earth to water, creating steam that turns turbines in electric generators.
• 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.
Energy Transformations and
Electric Energy (cont.)
Lesson 2-2
• 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.
Energy Transformations and
Electric Energy (cont.)
Lesson 2-2
Most of the energy used in the United States comes from nonrenewable energy resources.
Lesson 2-2
Energy Transformations and
Electric Energy (cont.)
What are renewable and nonrenewable energy resources?
Lesson 2 - VS
• 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.
Lesson 2 – LR1
A. conservation
B. work
C. closed system
D. open system
Which term refers the transfer of energy that occurs when a force makes an object move in the direction of the force?
Lesson 2 – LR2
A. closed system
B. energy resource
C. geothermal energy
D. open system
A car’s engine is an example of which of these?
Lesson 2 – LR3
A. open system
B. solar energy
C. nonrenewable energy resource
D. renewable energy resource
Which is an example of biomass?
Lesson 2 - Now
3. In most systems, no energy is transferred to the environment.
4. Some forms of energy are replenished naturally.
Do you agree or disagree?
Lesson 3 Reading Guide - KC
• What is the kinetic molecular theory?
• In what three ways is thermal energy transferred?
• How are thermal conductors and insulators different?
Particles in Motion
Lesson 3 Reading Guide - Vocab
• temperature
• heat
• conduction
• radiation
Particles in Motion
• convection
• vaporization
• thermal conductor
• thermal insulator
• The kinetic molecular theory explains how particles move and has three major points:
• All matter is made of particles.
• Particles are in constant, random motion.
• Particles constantly collide with each other and with the walls of their container.
Kinetic Molecular Theory
Particles that make up all matter are in constant motion. On average, solid particles move slowest, liquid particles move faster, and gas particles move the fastest.
Kinetic Molecular Theory (cont.)
What are the three points of the kinetic molecular theory?
• The measure of the average kinetic energy of the particles in a material is temperature.
• When the particles that make up a material move slowly, they occupy less volume than they do at a higher temperature.
• Thermal expansion is the increase in volume of a material due to a temperature increase.
Kinetic Molecular Theory (cont.)
When water is cooled to near its freezing point, interactions between water molecules push the molecules apart.
Kinetic Molecular Theory (cont.)
• As the kinetic energy of the particles that make up a material increases, the thermal energy of the particles increases.
• As the kinetic energy of the particles that make up a material decreases, the thermal energy of the particles decreases.
Kinetic Molecular Theory (cont.)
When you put a warm bottle of water in a cold refrigerator, thermal energy is transferred.
• The movement of thermal energy from a region of higher temperature to a region of lower temperature is called heat.
• When the temperatures of materials that are in contact are the same, the materials are said to be in thermal equilibrium.
Kinetic Molecular Theory (cont.)
Kinetic Molecular Theory (cont.)
equilibrium
from Latin aequus, means “equal”; and libra, means “a balance or scale”
• Conduction is the transfer of thermal energy by collisions between particles in matter.
• Radiation is the transfer of thermal energy by electromagnetic waves.
• Convection is the transfer of thermal energy by the movement of the particles from one part of a material to another.
Heat Transfer
Conduction, radiation, and convection are ways in which thermal energy is transferred.
Heat Transfer (cont.)
In what three ways is thermal energy transferred?
• Melting is the change of state from a solid to a liquid.
• Freezing is the change of state from a liquid to a solid.
Heat and Changes of State
• Vaporization is the change of state from a liquid to a gas.
• Vaporization that occurs within a liquid is called boiling.
• Vaporization that occurs at the surface of a liquid is called evaporation.
Heat and Changes of State (cont.)
• Sublimation is the change of state that occurs when a solid changes to a gas without passing through the liquid state.
• Deposition is the change of state from a gas directly to a solid without passing through the liquid state.
• Water vapor undergoes deposition when it freezes and forms frost.
Heat and Changes of State (cont.)
Heat and Changes of State (cont.)
sublime
Science Use to change from a solid state to a gas state without passing through the liquid state
Common Use inspiring awe; supreme, outstanding, or lofty in thought or language
• A thermal conductor is a material in which thermal energy moves quickly.
• A thermal insulator is a material in which thermal energy moves slowly.
Conductors and Insulators
Conductors and Insulators (cont.)
How do thermal conductors differ from thermal insulator?
Lesson 3 - VS
• The kinetic molecular theory explains how particles move in matter.
Lesson 3 - VS
• Thermal energy is transferred in various ways by particles and waves.
• Materials vary in how well they conduct thermal energy.
Lesson 3 – LR1
A. conduction
B. convection
C. heat
D. radiation
Which term refers to the transfer of thermal energy between particles in matter?
Lesson 3 – LR2
A. conduction
B. convection
C. radiation
D. vaporization
Which describes the transfer of thermal energy by the movement of particles from one part of a material to another?
Lesson 3 – LR3
A. deposition
B. melting
C. sublimation
D. vaporization
What is the change of state from a gas directly to a solid without passing through the liquid state?
Lesson 3 - Now
5. Only particles that make up moving objects are in motion.
6. Thermal energy can be transferred in several ways.
Do you agree or disagree?
Key Concept Summary
Interactive Concept Map
Chapter Review
Standardized Test Practice
Energy is involved in all physical processes; it is transferred when it moves from object to object without changing form. Energy is transformed when it is converted to another form. Energy is conserved during transfers and transformations.
• Potential energy is stored energy, and kinetic energy is energy of motion.
• Both mechanical energy and thermal energy involve kinetic energy and potential energy. Mechanical energy is the sum of the kinetic energy and the potential energy in a system of objects. Thermal energy is the sum of the kinetic energy and the potential energy in a system of particles.
• Sound energy and radiant energy are carried by waves.
Lesson 1: Forms of Energy
Lesson 2: Energy Transfers and
Transformations
• The law of conservation of energy says that energy can be transformed from one form to another, but it cannot be created or destroyed.
• Energy is transformed when it is converted from one form to another. It is transferred when it moves from one object to another.
• Renewable energy resources are resources that are replaced as fast as, or faster than they are used. Nonrenewable energy resources are resources that are available in limited quantities or are used faster than they can be replaced.
• The kinetic molecular theory says that all objects are made of particles; all particles are in constant, random motion; and the particles collide with each other and with the walls of their container.
• Thermal energy is transferred by conduction, radiation, and convection.
• A thermal conductor transfers thermal energy easily and a thermal insulator does not transfer thermal energy easily.
Lesson 3: Particles in Motion
A. mechanical energy
B. nuclear energy
C. sound energy
D. thermal energy
Which describes the sum of the potential energy and the kinetic energy in a system?
A. electric energy
B. kinetic energy
C. potential energy
D. radiant energy
Which refers to energy due to motion?
A. fossil fuel
B. natural gas
C. nonrenewable energy resource
D. renewable energy resource
Which term refers to an energy resource that is replaced as fast as, or faster than, it is used?
A. closed system
B. energy resource
C. open system
D. solar energy
Which term refers to a system that exchanges matter or energy with the environment?
A. conduction
B. deposition
C. heat
D. vaporization
Which refers to the movement of thermal energy from a region of higher temperature to a region of lower temperature?
A. energy
B. heat
C. wave
D. work
Which term refers to the ability to cause change?
A. gravitational potential energy
B. kinetic energy
C. nuclear energy
D. radiant energy
If an object has mass and height above Earth’s surface, what type of energy does it have?
A. chemical energy
B. nuclear energy
C. radiant energy
D. thermal energy
What type of energy is stored in and released from the nucleus of an atom?
A. energy transfer
B. solar energy
C. nonrenewable energy resources
D. renewable energy resources
Which term refers to energy resources that are available in limited amounts or that are used faster than they can be replaced in nature?
A. radiation
B. kinetic energy
C. thermal conductor
D. thermal insulator
Which is a material in which thermal energy moves slowly?
