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 TITLE : Unit 03: Investigating Force and Motion SUGGESTED DURATION : 25 days

#### Unit Overview

Introduction

This unit bundles Student Expectations addressing the relationship between force and motion. Unbalanced forces cause change in the motion of an object that can be measured and calculated. Speed is a ratio of distance traveled to time taken. Acceleration is the rate at which an object changes its velocity. Velocity is the change in position over the amount of time traveled.

Prior to this Unit

• 6.8B – Identify and describe the changes in position, direction, and speed of an object when acted upon by unbalanced forces.
• 6.8C – Calculate average speed using distance and time measurements.
• 6.8D – Measure and graph changes in motion.
• 6.3E – Multiply and divide positive rational numbers fluently.
• 6.10A – Model and solve one-variable, one-step equations and inequalities that represent problems, including geometric concepts.
• 6.12A – Represent numeric data graphically, including dot plots, stem-and-leaf plots, histograms, and box plots.
• 6.13A – Interpret numeric data summarized in dot plots, stem-and-leaf plots, histograms, and box plots.
• 7.3A – Add, subtract, multiply, and divide rational numbers fluently.
• 7.3B – Apply and extend previous understandings of operations to solve problems using addition, subtraction, multiplication, and division of rational numbers.

During this Unit

Students use scientific practices and a variety of tools to investigate, demonstrate (using models), and calculate how unbalanced forces change the speed or direction of an object's motion. Students calculate how a change in force affects the motion of an object. They also calculate the total net force acting upon an object by adding forces acting in the same direction or subtracting forces acting in opposite directions. Students also differentiate between speed, velocity, and acceleration. Furthermore, they are introduced to the relationship between force, mass, and acceleration (F=ma). Students manipulate the formula F=ma to understand how a change in force affects the acceleration (change in motion or direction) of an object. Students investigate and describe applications of Newton’s law of inertia, law of force and acceleration, and law of action-reaction. Students discuss their observations and record and organize data in their notebooks. Additionally, they analyze data to formulate reasonable explanations, communicate valid conclusions supported by the data, and predict trends. Students continue to demonstrate safe practices as outlined in the Texas Education Agency-approved safety standards and consider environmentally appropriate and ethical practices with resources during investigations.

Note: Students will be allowed the use of calculators on the Grade 8 Science STAAR Assessment.

Other considerations: Reference the Science COVID-19 Gap Implementation Tool Grade 8.

Streamlining Note

There are no revisions to 8.6A and 8.6B. TEKS 8.6C revised language to “Newton’s three laws of motion” vs. specific laws. See the Science TEKS Streamlining Side by Side Grade 8 (link in System Resources below).

After this Unit

In a subsequent unit, students will describe the applications of Newton’s laws in the context of Earth’s tectonic activities. Students will further their study concepts of force and motion in the High School Integrated Physics and Chemistry (IPC) or Physics course.

STAAR Note

The Grade 8 Science STAAR will directly assess Student Expectations in the following Reporting Categories:

• Reporting Category 2: Force, Motion, and Energy
• 8.6B – Supporting Standard

Research

The force / motion relationship can be developed more fully now and the difficult idea of inertia be given attention. Students have no trouble believing that an object at rest stays that way unless acted on by a force; they see it every day. The difficult notion is that an object in motion will continue to move unabated unless acted on by a force. Telling students to disregard their eyes will not do the trick—the things around them do appear to slow down on their own accord unless constantly pushed or pulled. The more experiences the students can have in seeing the effect of reducing friction, the easier it may be to get them to imagine the friction-equals-zero case.

“By the end of 8th grade, students should know that:

• An unbalanced force acting on an object changes its speed or direction of motion, or both. 4F/M3a”

 Scientists investigate natural phenomena in order to understand and explain each phenomenon in terms of systems. What is the value of knowing and understanding natural phenomena? How are the properties of systems and their components related to their classification? How are the components, processes, and / or patterns of systems interrelated?   Scientific investigation is an orderly process to ensure that scientific claims are credible. Why is credibility so important in the scientific field? How is scientific knowledge generated and validated?   Data is systematically collected, organized, and analyzed in terms of patterns and relationships to develop reasonable explanations and make predictions. What gives meaning to data? What is the value of observing patterns and relationships in data?   Scientists analyze, evaluate, and critique each other’s work using principles of scientific investigations in order to build on one another’s ideas through new investigations. How can we know what to believe about a scientific claim? In what ways have scientific explanations impacted scientific thought and society over time? What is the value of scientific literacy?
Unit Understandings
and Questions
Overarching Concepts
and Unit Concepts
Performance Assessment(s)

Unbalanced forces cause change in the motion of an object that can be measured and calculated.

• In what ways do unbalanced forces affect the motion of an object?
• Why can an object with balanced forces still be in motion? Justify with examples.
• In what ways can the relationship between force and motion be analyzed and demonstrated? Justify with examples.

Speed is a ratio of distance traveled to time taken.

• How can average speed be determined? Justify with examples.

Acceleration is the rate at which an object changes its velocity.

• In what ways does acceleration occur?

Velocity is the change in position over the amount of time traveled.

• In what ways does velocity occur?

Systems

• Force and motion

Classifications

• Balanced
• Unbalanced
• Speed
• Acceleration
• Velocity

Properties

• Equal size
• Unequal size
• Distance
• Time
• Changing speed or direction
• Speed and direction

Patterns

• Motion
• Energy

Constancy

• Balanced forces

Change

• Speed
• Position
• Direction
• Unbalanced forces
 Assessment information provided within the TEKS Resource System are examples that may, or may not, be used by your child’s teacher. In accordance with section 26.006 (2) of the Texas Education Code, "A parent is entitled to review each test administered to the parent’s child after the test is administered." For more information regarding assessments administered to your child, please visit with your child’s teacher.

Newton’s laws explain how an object’s motion is affected by balanced and unbalanced forces.

• In what ways do Newton’s laws explain the relationship between force and motion in real-world applications?

Systems

• Force and motion

Classifications

• Inertia
• Law of force and acceleration
• Law of action-reaction

Properties

• Balanced
• Unbalanced
• F = ma

Patterns

• Action-reaction
• Inertia
• F = ma

Constancy

• Balanced forces
• Inertia

Change

• Unbalanced forces
• Speed
• Position
• Direction
 Assessment information provided within the TEKS Resource System are examples that may, or may not, be used by your child’s teacher. In accordance with section 26.006 (2) of the Texas Education Code, "A parent is entitled to review each test administered to the parent’s child after the test is administered." For more information regarding assessments administered to your child, please visit with your child’s teacher.

#### MISCONCEPTIONS / UNDERDEVELOPED CONCEPTS

Misconceptions:

• Students may not recognize all of the forces acting upon an object because the forces are not visible.
• Students may think that acceleration is always positive, rather than any change in motion resulting in acceleration (e.g., starting, stopping, slowing down, speeding up, changing direction).
• Students may think of force as a property of an object (e.g., "an object has force" or "force is within an object"), rather than a relationship between the mass and acceleration of an object.
• Students may think action-reaction forces are always applied to the same object, rather than action-reaction force pairs that act upon two interacting objects.
• Students may think that an object without motion has no force acting on it, rather than a balanced force being applied.

#### Unit Vocabulary

Key Content Vocabulary:

• Acceleration – change in an object’s motion; caused by unbalanced forces
• Balanced force – equal and opposite forces on an object that result in no change in position, direction, or motion; net force equals zero
• Inertia – tendency of an object to resist change in motion
• Law of action-reaction – for every action, there is an equal and opposite reaction
• Law of force and acceleration – when an object that has a constant mass is acted upon by a force, the object will accelerate in the same direction as the force applied
• Law of inertia – the tendency of an object to resist change in motion unless acted upon by a force
• Net force – measurement of the total forces exerted on an object
• Speed – distance traveled by an object in a given amount of time
• Unbalanced force – unequal forces on an object that may result in a change in position, direction or motion; net force does not equal zero
• Velocity – a measurement of an object's speed and direction

Related Vocabulary:

 Applications Constant Force Force pairs Friction Gravity Mass Motion Newton Position Positive
Unit Assessment Items System Resources Other Resources

Show this message:

Unit Assessment Items that have been published by your district may be accessed through Search All Components in the District Resources tab. Assessment items may also be found using the Assessment Center if your district has granted access to that tool.

System Resources may be accessed through Search All Components in the District Resources Tab.

State:

Texas Education Agency – Griddable Questions for Science

http://www.tea.state.tx.us/student.assessment/staar/science/ (look under STAAR Science Resources)

Texas Education Agency – STAAR Grade 8 Science Reference Materials

Texas Education Agency – State Training: Science Academies: 5 - 8 Lessons: “Balanced and Unbalanced Forces” and “Force, Mass, and Acceleration”

Texas Education Agency – Texas Safety Standards

http://www.tea.state.tx.us/index2.aspx?id=5483 (look under Documents)

Texas Gateway for Online Resources by TEA – Changes in Speed and Direction

https://www.texasgateway.org/resource/changes-speed-and-direction

Texas Gateway for Online Resources by TEA – Newton’s Laws: Action and Reaction

https://www.texasgateway.org/resource/newton%E2%80%99s-laws-action-and-reaction

Texas Gateway for Online Resources by TEA –

Newton’s Laws: Force and Acceleration

https://www.texasgateway.org/resource/newton%E2%80%99s-laws-force-and-acceleration

Texas Gateway for Online Resources by TEA – Newton’s Laws: Inertia

https://www.texasgateway.org/resource/newton%E2%80%99s-laws-inertia

Texas Gateway for Online Resources by TEA – Newton’s Law of Action-Reaction

https://www.texasgateway.org/resource/newtons-law-action-reaction

Texas Gateway for Online Resources by TEA – Newton’s Law of Inertia

https://www.texasgateway.org/resource/newtons-law-inertia

Texas Gateway for Online Resources by TEA – Scientific Investigation and Reasoning – Data Organization

https://www.texasgateway.org/resource/scientific-investigation-and-reasoning-data-organization

Texas Gateway for Online Resources by TEA – Speed, Velocity, and Acceleration

https://www.texasgateway.org/resource/speed-velocity-and-acceleration

TAUGHT DIRECTLY TEKS

TEKS intended to be explicitly taught in this unit.

TEKS/SE Legend:

• Knowledge and Skills Statements (TEKS) identified by TEA are in italicized, bolded, black text.
• Student Expectations (TEKS) identified by TEA are in bolded, black text.
• Student Expectations (TEKS) are labeled Readiness as identified by TEA of the assessed curriculum.
• Student Expectations (TEKS) are labeled Supporting as identified by TEA of the assessed curriculum.
• Student Expectations (TEKS) are labeled Process standards as identified by TEA of the assessed curriculum.
• Portions of the Student Expectations (TEKS) that are not included in this unit but are taught in previous or future units are indicated by a strike-through.

Specificity Legend:

• Supporting information / clarifications (specificity) written by TEKS Resource System are in blue text.
• Unit-specific clarifications are in italicized, blue text.
• Information from Texas Education Agency (TEA), Texas College and Career Readiness Standards (TxCCRS), and American Association for the Advancement of Science (AAAS) Project 2061 is labeled.
• A Partial Specificity label indicates that a portion of the specificity not aligned to this unit has been removed.
TEKS# SE# TEKS SPECIFICITY
8.1 Scientific investigation and reasoning. The student, for at least 40% of instructional time, conducts laboratory and field investigations following safety procedures and environmentally appropriate and ethical practices. The student is expected to:
8.1A Demonstrate safe practices during laboratory and field investigations as outlined in Texas Education Agency-approved safety standards.
Process Standard

Demonstrate

SAFE PRACTICES DURING LABORATORY AND FIELD INVESTIGATIONS

Including, but not limited to:

• Wear appropriate safety equipment
• Know the location of safety equipment
• Follow classroom guidelines, as outlined in Texas Education Agency-approved safety standards
• Possible examples may include:
• Read or study the science activity or laboratory investigation prior to conducting the investigation
• Know and follow all safety rules prior to the investigation
• Be alert during the laboratory time
• Do not attempt unauthorized activities
• If a chemical spill occurs, report it immediately and follow the instructions of the teacher
• Do not enter preparatory or equipment storage rooms or chemical storerooms
• Always wash your hands for at least 20 seconds with soap and warm water before leaving the laboratory
• Use lab equipment appropriately

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• TEA:
• Project 2061: By the end of the 8th grade, students should know that:
• Science ethics demand that scientists must not knowingly subject coworkers, students, or community residents to health or property risks without their prior knowledge and consent. 1C/M5b*
• TxCCRS:
• I. Nature of Science – C2 – Understand and apply safe procedures in the laboratory and field, including chemical, electrical, and fire safety and safe handling of live or preserved organisms.
• I. Nature of Science – C3 – Demonstrate skill in the safe use of a wide variety of apparatuses, equipment, techniques, and procedures.
8.2 Scientific investigation and reasoning. The student uses scientific practices during laboratory and field investigations. The student is expected to:
8.2A Plan and implement comparative and descriptive investigations by making observations, asking well defined questions, and using appropriate equipment and technology.
Process Standard

Plan, Implement

COMPARATIVE AND DESCRIPTIVE INVESTIGATIONS

Including, but not limited to:

• Comparative and descriptive investigations
• Making observations
• Using appropriate equipment and technology

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• TEA:
• Comparative and descriptive investigations (Texas Education Agency. (2007-2011). Laboratory and Field Investigations – FAQ, August 2010. Retrieved from http://www.tea.state.tx.us/index2.aspx?id=5483)
• Comparative investigations involve collecting data on different organisms/objects/features/events, or collecting data under different conditions (e.g., time of year, air temperature, location) to make a comparison. The hypothesis identifies one independent (manipulated) variable and one dependent (responding) variable. A ―fair test* can be designed to measure variables so that the relationship between them is determined.
• Descriptive investigations involve collecting qualitative and/or quantitative data to draw conclusions about a natural or man-made system (e.g., rock formation, animal behavior, cloud, bicycle, electrical circuit). A descriptive investigation includes a question, but no hypothesis. Observations are recorded, but no comparisons are made and no variables are manipulated.
• * A fair test is conducted by making sure that only one factor (variable) is changed at a time, while keeping all other conditions the same.
• TxCCRS:
• I. Nature of Science – A3 – Formulate appropriate questions to test understanding of natural phenomena.
8.2B Design and implement experimental investigations by making observations, asking well defined questions, formulating testable hypotheses, and using appropriate equipment and technology.
Process Standard

Design, Implement

INVESTIGATIONS

Including, but not limited to:

• Experimental
• Making observations
• Formulating testable hypotheses
• Using appropriate equipment and technology

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• TEA:
• Comparative and experimental investigations (Texas Education Agency. (2007-2011). Laboratory and Field Investigations – FAQ, August 2010. Retrieved from http://www.tea.state.tx.us/index2.aspx?id=5483)
• Experimental investigations involve designing a ―fair test* similar to a comparative investigation, but a control is identified. The variables are measured in an effort to gather evidence to support or not support a causal relationship. This is often called a ―controlled experiment.
• * A fair test is conducted by making sure that only one factor (variable) is changed at a time, while keeping all other conditions the same.
• TxCCRS:
• I. Nature of Science – A3 – Formulate appropriate questions to test understanding of natural phenomena.
• I. Nature of Science – B1 – Design and conduct scientific investigations in which hypotheses are formulated and tested.
8.2C Collect and record data using the International System of Units (SI) and qualitative means such as labeled drawings, writing, and graphic organizers.
Process Standard

Collect, Record

DATA

Including, but not limited to:

• Quantitative means
• Using the International System of Units (SI)
• Qualitative means
• Labeled drawings
• Writing
• Graphic organizers

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• TxCCRS:
• I. Nature of Science – D3 – Demonstrate appropriate use of a wide variety of apparatuses, equipment, techniques, and procedures for collecting quantitative and qualitative data.
8.2D Construct tables and graphs, using repeated trials and means, to organize data and identify patterns.
Process Standard

Construct

TABLES AND GRAPHS

Including, but not limited to:

• Using repeated trials and means
• Organize data
• Identify patterns

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• TxCCRS:
• I. Nature of Science – E1 – Use several modes of expression to describe or characterize natural patterns and phenomena. These models of expression include narrative, numerical, graphical, pictorial, symbolic, and kinesthetic.
8.2E Analyze data to formulate reasonable explanations, communicate valid conclusions supported by the data, and predict trends.
Process Standard

Analyze

DATA

Including, but not limited to:

• Formulate reasonable explanations
• Making claims (statements) from data
• Providing evidence from data in order to support claims
• Communicate valid conclusions supported by data
• Using reasoning (argumentation) to explain or justify the claims
• Predict trends

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• Project 2061: By the end of the 8th grade, students should know that:
• Even with similar results, scientists may wait until an investigation has been repeated many times before accepting the results as correct. 1A/M1b
8.3 Scientific investigation and reasoning. The student uses critical thinking, scientific reasoning, and problem solving to make informed decisions and knows the contributions of relevant scientists. The student is expected to:
8.3A Analyze, evaluate, and critique scientific explanations by using empirical evidence, logical reasoning, and experimental and observational testing, so as to encourage critical thinking by the student.
Process Standard

Analyze, Evaluate, Critique

SCIENTIFIC EXPLANATIONS, SO AS TO ENCOURAGE CRITICAL THINKING BY THE STUDENT

Including, but not limited to:

• Use
• Empirical evidence
• Logical reasoning
• Experimental and observational testing

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• Project 2061: By the end of the 8th grade, students should know that:
• Scientific knowledge is subject to modification as new information challenges prevailing theories and as a new theory leads to looking at old observations in a new way. 1A/M2
• Some scientific knowledge is very old and yet is still applicable today. 1A/M3
• Scientific investigations usually involve the collection of relevant data, the use of logical reasoning, and the application of imagination in devising hypotheses and explanations to make sense of the collected data. 1B/M1b*
• If more than one variable changes at the same time in an experiment, the outcome of the experiment may not be clearly attributable to any one variable. It may not always be possible to prevent outside variables from influencing an investigation (or even to identify all of the variables). 1B/M2ab
• TxCCRS:
• I. Nature of Science – A1 – Utilize skepticism, logic, and professional ethics in science.
• I. Nature of Science – A4 – Rely on reproducible observations of empirical evidence when constructing, analyzing, and evaluating explanations of natural events and processes.
8.3D Relate the impact of research on scientific thought and society, including the history of science and contributions of scientists as related to the content.
Process Standard

Relate

THE IMPACT OF RESEARCH ON SCIENTIFIC THOUGHT AND SOCIETY

Including, but not limited to:

• History of science
• Contributions of scientists
• Possible examples may include:
• Isaac Newton (Newton’s laws of motion)

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• TxCCRS:
• IV. Science, Technology, and Society – C1 – Understand the historical development of major theories of science.
• IV. Science, Technology, and Society – C2 – Recognize the role of people in important contributions to scientific knowledge.
8.4 Scientific investigation and reasoning. Scientific investigation and reasoning. The student knows how to use a variety of tools and safety equipment to conduct science inquiry. The student is expected to:
8.4A

Use appropriate tools, including lab journals/notebooks, beakers, meter sticks, graduated cylinders, anemometers, psychrometers, hot plates, test tubes, spring scales, balances, microscopes, thermometers, calculators, computers, spectroscopes, timing devices, and other necessary equipment to collect, record, and analyze information.

Process Standard

Use

APPROPRIATE TOOLS TO COLLECT, RECORD, AND ANALYZE INFORMATION

Including, but not limited to:

• Lab journal / (science) notebooks
• Meter sticks
• Spring scales
• Balances
• Calculators
• Computers
• Timing devices
• Other equipment as needed to teach the curriculum

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• TxCCRS:
• I. Nature of Science – D3 – Demonstrate appropriate use of a wide variety of apparatuses, equipment, techniques, and procedures for collecting quantitative and qualitative data.
8.4B Use preventative safety equipment, including chemical splash goggles, aprons, and gloves, and be prepared to use emergency safety equipment, including an eye/face wash, a fire blanket, and a fire extinguisher.
Process Standard

Use

SAFETY EQUIPMENT

Including, but not limited to:

• Preventative safety equipment
• Chemical splash goggles
• Aprons
• Gloves
• Emergency safety equipment
• Eye / face wash
• Fire blanket
• Fire extinguisher

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• TxCCRS:
• I. Nature of Science – C3 – Demonstrate skill in the safe use of a wide variety of apparatuses, equipment, techniques, and procedures.
8.6 Force, motion, and energy. The student knows that there is a relationship between force, motion, and energy. The student is expected to:
8.6A Demonstrate and calculate how unbalanced forces change the speed or direction of an object's motion.

Demonstrate, Calculate

HOW UNBALANCED FORCES CHANGE AN OBJECT’S MOTION

Including, but not limited to:

• Balanced forces – equal and opposite forces on an object that result in no change in position, direction, or motion; net force equals zero
• Unbalanced forces – unequal forces on an object that may result in a change in position, direction, or motion; net force does not equal zero
• Effect of unbalanced forces
• Acceleration – change in an object’s motion; caused by unbalanced forces
• Dependent upon mass
• Lighter objects will accelerate easier than heavier objects when the same force is applied to both objects
• Lighter objects are easier to stop than heavier objects when the same force is applied to both objects
• Position (displacement)
• Direction
• Motion
• Speed
• Examples of acceleration
• Starting / stopping
• Speeding up / slowing down
• Changing direction
• Possible additional examples of acceleration may include:
• A cart rolling down a ramp
• A boat traveling in the current of a river
• A vehicle traveling in a curve
• Examples of effects of unbalanced forces
• Direction
• Forces acting in the same direction can be added together for total net force
• Forces acting in opposing directions can be subtracted for the total net force
• With opposing forces, the object will move in the direction of the greater force
• Speed
• Average speed = total distance/total time
• s = d2 d1 / t2 – t1
• s = d / t
• Velocity is expressed by both speed and direction (e.g., 55 km/hr east)
• Force
• Net force = mass x acceleration
• F = ma
• Acceleration
• Acceleration = force / mass
• a = F / m
• Positive or negative
• Mass
• Mass = force / acceleration
• m = F / a
• Gravity
• Inertia
• Friction

Note(s):

• STAAR:
• The STAAR Grade 8 Reference Materials include the formulas for average speed and net force as listed above.
• Students may be asked to manipulate the formula (F = ma).
• Students may be required to interpret the relationship between force, mass, and acceleration.
• Students in Grade 6 have been introduced to the effects of unbalanced forces on objects (6.8B).
• Students will be allowed the use of calculators on the Grade 8 Science STAAR assessment.
• Project 2061: By the end of the 8th grade, students should know that:
• An unbalanced force acting on an object changes its speed or direction of motion, or both. 4F/M3a
• TxCCRS:
• VIII. Physics – C1 – Understand the fundamental concepts of kinematics.
• VIII. Physics – C2 – Understand forces and Newton’s Laws.
8.6B Differentiate between speed, velocity, and acceleration.
Supporting Standard

Differentiate

BETWEEN SPEED, VELOCITY, ACCELERATION

Including, but not limited to:

• Speed
• Average speed = total distance / total time
• s = d2 – d1 / t2 – t1
• s = d / t
• Velocity is expressed by both speed and direction (e.g., 20 km/hr north)
• Acceleration
• Caused by unbalanced forces
• Examples of acceleration
• Change in motion
• Starting / stopping
• Speeding up / slowing down
• Change in direction
• Possible scenario of acceleration may include:
• A car maintaining a constant speed in a curve

Note(s):

• STAAR:
• The STAAR Grade 8 Reference Materials include the formula for average speed as listed above.
• Students may be required to convert units of measure (seconds to hours) prior to calculations.
• Students may be required to analyze a graph to describe the motion of an object.
• Students in Grade 6 have been introduced to average speed (6.8C).
• Students will be allowed the use of calculators on the Grade 8 Science STAAR assessment.
• TxCCRS:
• II. Foundation Skills: Scientific Applications of Mathematics – A5 – Simplify algebraic expressions.
• II. Foundation Skills: Scientific Applications of Mathematics – B1 – Carry out formal operations using standard algebraic symbols and formulae.
• VIII. Physics – C1 – Understand the fundamental concepts of kinematics.
8.6C Investigate and describe applications of Newton's three laws of motion such as in vehicle restraints, sports activities, amusement park rides, Earth's tectonic activities, and rocket launches.

Investigate, Describe

APPLICATIONS OF NEWTON’S THREE LAWS OF MOTION

Including, but not limited to:

• Newton’s laws
• Law of inertia – the tendency of an object to resist change in motion unless acted upon by a force
• An object in motion will remain in motion, at a constant speed, in a straight line, until acted upon by an unbalanced force
• An object at rest will remain at rest until acted upon by an unbalanced force
• Relationship to mass
• Law of force and acceleration – when an object that has a constant mass is acted upon by a force, the object will accelerate in the same direction as the force applied
• Relationship between force, mass, and acceleration
• Force
• Net force = mass x acceleration
• F = ma
• Acceleration
• Acceleration = net force / mass
• a = F / m
• Positive or negative
• Calculating net force by adding or subtracting forces applied to an object may be required prior to solving for acceleration (2017 STAAR, #25)
• Mass
• Mass = net force / acceleration
• m = F / a
• Calculating net force by adding or subtracting forces applied to an object may be required prior to solving for acceleration
• Law of action - reaction – for every action, there is an equal and opposite reaction
• All forces act in pairs. (Action: Object A exerts a force on Object B; Reaction: Object B exerts an equal and opposite force on Object A)
• Applications of Newton’s laws in:
• Vehicle restraints
• Sports activities
• Amusement park rides
• Earth’s tectonic activities
• Rocket launches
• Possible additional application examples may include:
• Cars of different masses
• Friction from surface texture affects the acceleration of an object

Note(s):

• STAAR:
• This is the first time students have been introduced to Newton’s laws.
• The STAAR Grade 8 Reference Materials include the formula for net force as listed above.
• Students may be presented with only one variable of F = ma, either acceleration or mass, and have to calculate net force by adding or subtracting forces applied to an object prior to solving for acceleration or mass (2017 STAAR, #25).
• Students will be allowed the use of calculators on the Grade 8 Science STAAR assessment.
• TxCCRS:
• VIII. Physics – A3 – Understand the concepts of mass and inertia.
• VIII. Physics – C1 – Understand the fundamental concepts of kinematics.
• VIII. Physics – C2 – Understand forces and Newton’s Laws.
DEVELOPING TEKS

TEKS that need continued practice, improvement, and refinement, but do not necessarily need to be explicitly taught in this unit.

TEKS/SE Legend:

• Knowledge and Skills Statements (TEKS) identified by TEA are in italicized, bolded, black text.
• Student Expectations (TEKS) identified by TEA are in bolded, black text.
• Student Expectations (TEKS) are labeled Readiness as identified by TEA of the assessed curriculum.
• Student Expectations (TEKS) are labeled Supporting as identified by TEA of the assessed curriculum.
• Student Expectations (TEKS) are labeled Process standards as identified by TEA of the assessed curriculum.
• Portions of the Student Expectations (TEKS) that are not included in this unit but are taught in previous or future units are indicated by a strike-through.

Specificity Legend:

• Supporting information / clarifications (specificity) written by TEKS Resource System are in blue text.
• Unit-specific clarifications are in italicized, blue text.
• Information from Texas Education Agency (TEA), Texas College and Career Readiness Standards (TxCCRS), and American Association for the Advancement of Science (AAAS) Project 2061 is labeled.
TEKS# SE# TEKS SPECIFICITY
8.1 Scientific investigation and reasoning. The student, for at least 40% of instructional time, conducts laboratory and field investigations following safety procedures and environmentally appropriate and ethical practices. The student is expected to:
8.1B Practice appropriate use and conservation of resources, including disposal, reuse, or recycling of materials.
Process Standard

Practice

APPROPRIATE USE AND CONSERVATION OF RESOURCES

Including, but not limited to:

• Use of resources
• Disposal of materials
• Laboratory materials
• Conservation of resources
• Reuse of materials
• Recycling of materials
• Paper
• Glass
• Plastic
• Metal

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• Project 2061: By the end of the 8th grade, students should know that:
• Recycling materials and the development of substitutes for those materials can reduce the rate of depletion of resources but may also be costly. Some materials are not easily recycled. 4B/M10c*
• The wasteful or unnecessary use of natural resources can limit their availability for other purposes. Restoring depleted soil, forests, or fishing grounds can be difficult and costly. 4B/M11a*
• The benefits of Earth's resources—such as fresh water, air, soil, and trees—can be reduced by deliberately or inadvertently polluting them. The atmosphere, the oceans, and the land have a limited capacity to absorb and recycle waste materials. In addition, some materials take a long time to degrade. Therefore, cleaning up polluted air, water, or soil can be difficult and costly. 4B/M11bc*
8.3 Scientific investigation and reasoning. The student uses critical thinking, scientific reasoning, and problem solving to make informed decisions and knows the contributions of relevant scientists. The student is expected to:
8.3B Use models to represent aspects of the natural world such as an atom, a molecule, space, or a geologic feature.
Process Standard

Use

MODELS

Including, but not limited to:

• Representing aspects of the natural world
• An atom
• A molecule
• Space
• A geologic feature
• Possible examples may include:
• Physical models
• Effects of the Moon on tides
• Conceptual models
• Lunar cycle
• Periodic Table
• Mathematical models

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
8.3C Identify advantages and limitations of models such as size, scale, properties, and materials.
Process Standard

Identify

Including, but not limited to:

• Size
• Scale
• Properties
• Materials

Note(s):

• STAAR:
• The process skills will be incorporated into at least 40% of the test questions and will be identified along with content standards.
• TxCCRS:
• V. Cross-Disciplinary Themes – E2 – Use scale to relate models and structures.
• VII. Chemistry – B1 – Summarize the development of atomic theory. Understand that models of the atom are used to help understand the properties of elements and compounds.