# Gr 8 Unit 4 Revised by keralaguest

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```									                                           Grade 8

UNIT FOUR: INVESTIGATING THE RELATIONSHIP
BETWEEN ENERGY AND HEAT TRANSFER

Overview
In this unit the student will be able to differentiate between potential (elastic, chemical,
gravitational) and kinetic energy. Students will analyze the transfer of potential to kinetic energy
and kinetic to potential energy and utilize the information to provide explanations for common
situations including a roller coaster ride and jumping on a trampoline. Students will be able to
identify and give examples of the common forms of energy (light, heat, chemical, electrical,
mechanical, and nuclear energy). The relationship of heat and molecular kinetic activity will be
explored by examining the results of the addition or subtraction of heat energy on the motion of
the molecules. In addition, students will be able to differentiate between heat and temperature in
terms of molecular activity. The Celsius and Kelvin temperature scales will be compared and
contrasted and absolute zero will be described. Conduction, convection, and radiation will be
compared and contrasted and an explanation of common examples of each will be made.
Students will be able to explain in simple terms how the principles of heat transfer apply to heat
engines, thermostats, and refrigerators. The objectives in this unit can be covered in an order
determined by the teacher to provide a smooth flow of information.

Background Information
Energy is the ability to do work. The two states of energy are kinetic and potential energy.
Potential energy is energy stored based on position or chemical composition. The amount of
potential energy associated with an object depends on its position. An apple in a tree keeps its
potential (stored) energy due to its height above the ground.

Kinetic energy is energy of motion. If the apple falls, the stored energy from its position is then
converted to kinetic energy (energy of motion). The amount of kinetic energy depends on the
mass and velocity of the moving object.

The primary forms of energy include mechanical, electrical, chemical, heat, light, sound, and
nuclear. (Sound is a form of mechanical energy)

Grade 8 Curriculum – Unit 4                                                                 Page 45
Atoms and molecules are perpetually in motion. Increased temperature means greater kinetic
energy (energy of motion), as well as molecular expansion on most substances when heated.
The temperature of absolute zero (-273 degrees C/ 0 degrees K) is the only situation in which
theoretically there is no atomic/molecular motion.

Heat, on the other hand, is not the same thing as temperature. As heat energy is added to or
taken away from a system, the temperature does not always change. There is no change in
temperature during a phase change (freezing, melting, condensing, boiling, and vaporizing).

Energy can be transformed from one type to another. Energy in the form of heat is one of the
by-products of any energy transformation. Heat energy can be transferred by means of

Energy transformations occur in simple devices like toasters, light bulbs, motors, and hair dryers.
In a toaster, electrical energy is the input. The outputs (energy production) are heat and light
energy.

Grade 8 Curriculum – Unit 4                                                                Page 46
Concept Map

Relationship Between Energy & Heat Transfer

Forms of         Potential Energy      Kinetic Energy        Transfer of     Transfer of
Energy            Stored Energy        Energy in the      Thermal Energy      Energy
Due to Position      Form of Motion

Light                                                                       PE  KE; KE  PE


Molecular           Conduction
Elastic
Motion
Electricity  Light
Heat
Motion of           Convection
Chemical
Objects                            Chemical Energy 
Thermal Energy
Chemical
Gravitational
Mechanical  Sound
Electrical

Chemical PE 
Electrical  Thermal
Mechanical                                                                        Energy  KE

Chemical PE 
Nuclear
Friction  Thermal
Energy
Energy

Chemical PE  KE

Electrical  Thermal
+ Light

Grade 8 Curriculum – Unit 4                                                                    Page 47
Suggested Time Allotment
2 Weeks

Enduring Understandings
 Energy is transferred in many ways and energy changes forms, which cannot be created
nor destroyed.

Essential Questions
 What vocabulary do scientists use when discussing energy?
 What is the sequence of methods that can be used in scientific research or in other
information management processes?
 What are the two states of energy?
 What are the primary forms of energy?
 What is the definition of energy?
 What is the difference between heat and temperature?
 What are three ways heat energy can be transferred?
 What are some examples of devices that transform energy from one form to another?
 What is the energy input and output in each device?

Instructional Objectives and Enablers
8.4.1 Define key terminology associated with unit

8.4.2 Differentiate between potential (elastic, chemical, gravitational) and kinetic energy

8.4.3 Analyze and describe the transfer of energy (potential to kinetic and vice versa) that take
place in everyday life including a roller coaster ride and a person using a trampoline

8.4.4 Using diagrams or concrete examples to compare relative amounts of potential kinetic
energy

8.4.5 Identify and give examples of common forms of energy (light, heat, chemical, electrical,
mechanical, and nuclear energy)

8.4.6 Relate heat and molecular kinetic activity by illustrating and explaining the results of
addition or subtraction of heat energy on the motion of molecules

8.4.7 Differentiate between heat and temperature in terms of molecular activity

Grade 8 Curriculum – Unit 4                                                                  Page 48
8.4.8 Compare and contrast Celsius and Kelvin temperature scales and describe absolute zero

8.4.9 Analyze a time/temperature graph of a phase change experiment to determine the
temperature at which the phase change occurs (freezing point, melting point, or boiling
point)

8.4.10 Compare and contrast conduction, convection, and radiation and provide and explain
common examples of each

8.4.11 Explain in simple terms how the principles of heat transfer applies to heat engines,
thermostats, and refrigerators

8.4.12 Design an investigation or create a diagram to illustrate energy transformations

8.4.13 Design, analyze, and critique an investigation from a testable question related to heat
transfer (refer to standard one for specific details regarding essential skills for
experimental design)

Virginia Standards of Learning
PS.6   The student will investigate and understand states and forms of energy and how energy is
transferred and transformed. Key concepts include
a) potential and kinetic energy;
b) mechanical, chemical, and electrical energy; and
c) heat, light, and sound.

PS.7   The student will investigate and understand temperature scales, heat, and heat transfer.
Key concepts include
a) Celsius and Kelvin temperature scales and absolute zero;
b) phase change, freezing point, melting point, boiling point, vaporization, and
condensation;
c) conduction, convection, and radiation; and
d) applications of heat transfer (heat engines, thermostats, refrigeration, and heat
pumps).

Grade 8 Curriculum – Unit 4                                                               Page 49
Instructional Resources
Text References
Physical Science
Glencoe

Chapter 16, “Solids, Liquids, and Gases”
Section 1, “Kinetic Theory” (Review) p. 488-492

WYMSO (What You May Safely Omit)
Section 1, “Kinetic Theory” p. 493-495
Section 2, “Properties of Fluids” p. 497-501
Section 3, “Behavior of Gases” p. 502 - 507

Chapter 1, “The Nature of Science”
Section 2, “Standards of Measurement” (Review) p. 19-21

WYMSO (What You May Safely Omit)
Section 1, “Methods of Science” p.6-13
Section 3, “Communicating with Graphs” p.22-26

Chapter 4, “Energy”
Section 1, “The Nature of Energy,” p. 100-105
Section 2, “Conservation of Energy,” p. 107-111

WYMSO (What You May Safely Omit)
Section 2, “Conservation of Energy” p. 112-115

Chapter 6, “Thermal Energy”
Section 1: “Temperature and Heat,” p. 158-160
Section 2: “Transferring Thermal Energy,” p. 164-167, 169-170
Section 3: “Using Heat,” p. 172-178

WYMSO (What You May Safely Omit)
Section 1: “Specific Heat” p. 161-163
Section 2: “Controlling Heat Flow” p. 168
Section 3: “The Human Coolant” p. 179

Grade 8 Curriculum – Unit 4                                            Page 50
Ancillary Resources
Chapter Resources             Chapter 1     “The Nature of Science”
Chapter 4     “Energy”
Chapter 6     “Thermal Energy”
Chapter 16    “Solids, Liquids, and Gases”
Physical Science Examview Pro Test Bank

Other Resources
Physical Science Examview Pro Test Bank
Glencoe Physical Science Puzzle Maker
Physical Science Standardized Test Practice
Physical Science Laboratory Activities Manual
Dinah Zike’s Teaching Science With Foldables
Critical Thinking/Problem Solving Resources Booklet “Energy Saving Refrigerators” p. 8

Choices For Evaluating The Unit
The following section contains activities that can be used to evaluate the unit. There are far more
activities listed than can be used in the allotted time for this unit. The teacher should choose
activities that will provide information on the students understanding of the objectives being
covered.
Preassessment
 5-3-1 Have students list five things they know about potential/kinetic energy, 3 questions
they have and one application they can give using the terms.
 Bell Ringer Transparency p. 42 in Chapter 4 Chapter Resources
 Ask students to describe how the word energy is commonly used.
 Have students list as many types of energy as they can.

Formative Assessment
 Non-Fiction Writing: Have students make a list in their Science Journals of the different
types of energy mentioned in the text. Have them list several examples of how they use
each form of energy every day.
 Quick Non-Fiction Writing: Have students write about thermal energy and heat. See p.
159 for details regarding the strategy of quick writes.
 Ask students to make an events chain for each of the convection currents observed in the
lab on p. 171.
 Have students describe the energy transformation that takes place as you go up and down
a hill.

Grade 8 Curriculum – Unit 4                                                                Page 51
Summative Assessment
 Demonstrate how the bounce height of a ball becomes lower and lower each time it
bounces. Have students write why this happens.
 Have students research the types of heating that are common in the Tidewater area and
why, and find information about initial cost, efficiency, and maintenance requirements of
different systems. Work with the Language Arts teacher to facilitate this project.

Essential Terminology
Boiling Point                 Temperature at which the pressure of the atmosphere is equal to the
pressure of a liquid’s vapor, and the gas molecules can escape the
attractive force between the molecules.

Gravitational
Potential Energy              Energy stored by things attracted to each other by the force of gravity

Heat                          Thermal energy that flows from a warmer material to a cooler
material; is measured in joules

Heat engine                   Device that converts thermal energy produced by combustion into
mechanical energy

Heat mover                    A device, such as a refrigerator, that removes thermal energy from one
place and transfers it to another place and transfers it to another place
at a different temperature

Kinetic energy                Energy in the form of motion; depends on the mass and velocity of the
object

Mechanical energy             Sum of potential and kinetic energy in a system

Potential Energy              Stored energy due to position; can be converted to kinetic energy when
something acts to release it

Temperature                   A measure of the average kinetic energy of all particles in the object

Elastic
Potential Energy              Energy stored by things that are stretched

Chemical
Potential Energy              Energy stored in chemical bonds

Grade 8 Curriculum – Unit 4                                                                    Page 52
Choices For Introducing The Unit
The following section contains an activity that can be used to introduce the unit. The teacher may
substitute an alternate activity that effectively introduces the information found in the unit.

 Use the Explore Activity on p. 99 to introduce the students to the conversion of
electricity of light and heat. Be sure to have the students complete “Observe” and
“Assessment” sections within their lab report.

Choices For Teaching The Unit
This section contains choices for teaching the unit by objective. All of the objectives presented
should be covered, but it is not required that they be covered in the order presented in this
section. There are far more activities listed than can be used in the allotted time for this unit. The
teacher should choose activities that will lead the students to mastery of the objectives and
success on the evaluation component of this unit.

Topic                         Objective                      Suggested Activities

Terminology                  8.4.1 Define key terminology         Foldables p. 17 in Chapter 6
associated with unit.                 Chapter Resources
PS 6                                 Foldables p. 17 in Chapter 4
Chapter Resources
Mastery “Overview of
Energy” p. 19 in Chapter 4
Chapter Resources
 Mini Lab:” Interpreting Data
from a Slingshot” p. 3 in
Chapter 4 Chapter Resource

Potential vs. Kinetic        8.4.2 Differentiate between          Activity: “Transforming
Energy                       potential (elastic, chemical,         Energy Using A Paper Clip”
gravitational) and kinetic            p. 4 in Chapter 4 Chapter
energy (M)                            Resource
PS 6

Grade 8 Curriculum – Unit 4                                                                   Page 53
Topic                         Objective                     Suggested Activities

Transfer of Energy           8.4.3 Analyze and describe the       Activity: “Bouncing Balls” p.
transfer of energy (potential to      5 in Chapter 4 Chapter
kinetic and vice versa) that take     Resources
place in everyday life including     Lab Activity: “The Energy of
a roller coaster ride and a           a Pendulum” p. 9-12 in
person using a trampoline             Chapter 4 Chapter Resources
PS 6                                 Enrichment Transferring
Kinetic and Potential Energy
p. 29 in Chapter 4 Chapter
Resources

Potential kinetic energy     8.4.4 Using diagrams or              Lab Activity: “The Energy of
concrete examples to compare          a Pendulum” p. 9-12 in
relative amounts of potential         Chapter 4 Chapter Resources
kinetic energy                       Enrichment “Transferring
PS 6                                  Kinetic and Potential Energy”
p. 29 in Chapter 4 Chapter
Resources
 “Make a Model” Activity p.
108 - Have students work in
groups to make a model that
shows conversions between
potential energy to kinetic
energy

Forms of Energy              8.4.5 Identify and give              Bellringer Transparency p. 43
examples of common forms of           in Chapter 4 Chapter
energy (light, heat, chemical,        Resources
electrical, mechanical, and
nuclear energy)
PS 6

Heat & Molecular             8.4.6 Relate heat and                Drawing: Have students draw
Kinetic Activity             molecular kinetic activity by         in their science journals
illustrating and explaining the       diagrams relating to the
results of addition or                molecular activity
subtraction of heat energy on        Explore Activity p. 157 in TE
the motion of molecules
PS 7

Heat vs. Temperature         8.4.7 Differentiate between          Bellringer Transparency
heat and temperature in terms         “Crumbling Bloom” p. 44 in
of molecular activity                 Chapter 6 Chapter Resources
PS 7                                 Explore Activity p. 157 in TE

Grade 8 Curriculum – Unit 4                                                                 Page 54
Topic                        Objective                     Suggested Activities

Temperature Scales           8.4.8 Compare and contrast
Celsius and Kelvin
temperature scales and
describe absolute zero
PS 7

Phase Change                 8.4.9 Analyze a                    Activity: Kinetic Theory p.29
time/temperature graph of a         Chapter 16 Chapter Resource
phase change experiment to
determine the temperature at
which the phase change occurs
(freezing point, melting point,
or boiling point)
PS 7

Conduction,                  8.4.10 Compare and contrast        Activity: “Convection in
Convection, and              conduction, convection, and         Gases and Liquids” p. 171
explain common examples of          own data table for this
each                                activity); or p. 5-6 in Chapter
PS 7                                6 Chapter Resources
 Activity: “Conduction in
Gases” p. 7-8 in Chapter 6
Chapter Resources
 MiniLab p. 168 in TE
“Observing Heat Transfer by
Radiation”; or p. 3 in Chapter
6 Chapter Resources
 Mini Lab: “Comparing
Thermal Conductors” p. 169
in TE; or p. 4 in Chapter 6
Chapter Resources

Heat Transfer                8.4.11 Explain in simple terms  Engage students in a
how the principles of heat       discussion using the following
transfer applies to heat         prompt: “Would you prefer to
engines, thermostats, and        own a car with a four-cylinder,
refrigerators                    six-cylinder, or eight-cylinder
PS 7                             engine? Why?” (Use the
Cooperative Learning
Structure: Round Table to
facilitate the discussion-see p.
176 in TE)

Grade 8 Curriculum – Unit 4                                                                Page 55
Topic                         Objective                      Suggested Activities

Energy Transformation        8.4.12 Design an investigation       Activity: Design Your Own
or create a diagram to illustrate     Experiment: “Swinging
energy transformations                Energy” p. 116-117; or p. 7-8
PS 7                                  in Chapter 4 Chapter
Resources
 Activity: “Bouncing Balls” p.
106

Experimental Design          8.4.13 Design, analyze, and          Activity: “Convection in
critique an investigation from        Gases and Liquids” p. 171
a testable question related to        (Students should create their
heat transfer (refer to standard      own data table for this
one for specific details              activity); or p. 5-6 in Chapter
regarding essential skills for        6 Chapter Resources
experimental design)                 Activity: “Conduction in
PS 7                                  Gases” p. 7-8 in Chapter 6
Chapter Resources

Grade 8 Curriculum – Unit 4                                                                   Page 56

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