8th Grade - Unit 1: Motion in the Universe

Instructional Sequence

Assessment Types at
This Stage

Assessment Description

Learning Target

Engage

Observations: Students’ background knowledge about motion can be assessed. 

Students investigate different ways to move small objects at their tables using their bodies and simple tools provided. Students explore how they can tell that motion is occurring. Students explore how the motion of an object can be changed.

It is okay if students are not sure that positions of objects and the directions of motions must be described in an arbitrarily chosen reference frame.

Explore 1

Observations, Drawing Models, Written Responses:  

Students record observations and draw models based on demonstrations, a hands-on activity, and a computer simulation. 

In Part 1, students observe demonstrations of Newton’s first law of motion related to objects at rest and draw diagrams explaining what they observe. In Part 2, students answer thought experiment questions related to objects in motion related to Newton’s first law of motion. In Part 3, students explain and draw diagrams about unbalanced and balanced forces applied to a book on a desk. In Part 4, students answer questions and draw diagrams about unbalanced and balanced forces as observed in a computer simulation. 

Students should be able to

• Record observations from demonstrations, an activity, and a computer simulation that relate to Newton’s first law of motion. 
• Provide written explanations and diagrams about what happens when unbalanced and balanced forces are applied to an object. 

Explain 1

Reading, Group Discussion:

Students read an article, working with partners, and Listening Triads. Students answer Reflection Questions in small groups and discuss responses as a class. 

Students engage in a close-reading protocol and answer questions about the article “Newton’s First Law of Motion” using the Listening Triads protocol. Section 1 of the article covers motion, Section 2 covers unbalanced and balanced forces, and Section 3 covers Newton’s first law of motion. At the end of each section, students work together to answer Reflection Questions based on the article. 

Students should be able to 

• Complete a close-reading protocol of an article on Newton’s first law of motion. 
• Explain that positions of objects and the directions of motions must be described in an arbitrarily chosen reference frame.
• Explain how unbalanced and balanced forces affect the motion of an object. 
• Explain Newton’s first law of motion.

Explore 2

Observations, Drawing Models, Written Responses:  

Students record observations and draw models based on a computer simulation. Optionally, teachers may present a demonstration in which an unbalanced force accelerates an object. 

Students explore Newton’s second law of motion using a computer simulation. Students explore how changes in force can affect the acceleration of different objects. Students observe how force, mass, and acceleration are related. 

Students should be able to

• Record observations and draw diagrams of what they observe from the computer simulation when forces are applied to objects of different masses. 
• Collect data that shows how varying the amount of force on the same object (same mass) affects the acceleration of that object.

• Collect data that shows how applying the same force to different objects with varying amounts of mass affects the acceleration of the objects. 
• Explore how an unbalanced net force acting on an object results in changes in the acceleration of that object. 
• Optionally, students can record observations and try to explain how a marshmallow is accelerated by an unbalanced force. 

Explain 2

Reading, Group Discussion:

Students read an article, working with partners and Listening Triads. Students answer Reflection Questions in small groups and discuss responses as a class. 

In Part 1, students engage in the close-reading protocol and answer questions about the article “Newton’s Second Law of Motion” using the Listening Triads protocol. Part 2 includes some problems related to Newton’s second law of motion for the class to solve together. 

Students should be able to 

• Complete a close-reading protocol of an article on Newton’s second law of motion.
• Explain how varying the amount of force on the same object (same mass) affects the acceleration of that object.
• Explain how applying the same force to different objects with varying amounts of mass affects the acceleration of the objects.
• Work together as a class to solve problems using Newton’s second law of motion.

Explore 3

Observations, Drawing Models, Written Responses:  

Students record observations and draw models based on demonstrations and a hands-on activity. 

In Part 1, students explore Newton’s third law of motion by observing a demonstration. In Part 2, students watch two videos about Newton’s third law. Finally, students build simple balloon rockets to explore Newton’s third law.

Students should be able to 

• Observe and explain three demonstrations that illustrate Newton’s third law of motion.
• Build simple balloon rockets to explore Newton’s third law of motion. 
• Provide written explanations and diagrams about what they observe. 

Explain 3

Reading, Group Discussion:

Students read an article, working with partners, and Listening Triads. Students answer Reflection Questions in small groups and discuss responses as a class. 

In Part 1, students engage in the close-reading protocol and answer questions about the article “Newton’s Third Law of Motion” using the Listening Triads protocol. In Part 2, students use what they have learned to revise explanations of how the balloon rockets work. 

Students should be able to 

• Complete a close-reading protocol of an article on Newton’s third law of  motion. 
• Explain that for any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction. 
• Revise explanations for the motion of the balloon rockets using information from the article.

Elaborate

Extending Understanding and Applying Learning to a New Context: Students apply their understanding of contact forces to try to prevent two objects from colliding. 

In the Elaborate lesson, students consider two situations in which unbalanced forces are used to prevent a collision. In each situation, two people are moving at constant speed on paths that will intersect. Students must use their understanding of Newton’s laws of motion to explain how the collisions can be prevented. 

Students should be able to 

• Describe how a collision between two moving objects can be prevented using a contact force. 
• Provide written explanations and diagrams about what they observe.

Evaluate

Evaluating, Communicating Information, Drawing Models, Written Responses: Students demonstrate their understanding and evaluate their knowledge of Newton’s laws of motion. Students apply what they have learned about contact forces to the problem posed in the Culminating Project. 

In Part 1, students use a Critique, Correct, Clarify routine to edit a statement that a fictional student has made about motion. In Part 2, students work individually, with a small group, and as a whole class to create a concept map to summarize what they have learned in the subunit. Finally, students work together to connect the concepts they have learned to the Culminating Project. Students return to the situations described in the Elaborate lesson and apply what they have learned to the Culminating Project. 

Students should be able to 

• Critique, Correct, and Clarify an incorrect statement about the laws of motion. 
• Work together as a class to build a class concept map related to the content covered in Subunit 1. 
• Show how a contact force could be used to prevent the asteroid from hitting Earth and explain how Newton’s laws of motion relate to changing the motion of the asteroid.

Instructional Sequence

Assessment Types at
This Stage

Assessment Description

Learning Target

Engage

Observations: Students’ background knowledge about non-contact forces is addressed. 

Students are presented with a variety of objects and have the goal of trying to move objects without directly touching them. 

Students should be able to 

• Access their background knowledge about forces that can act at a distance. 
• Investigate different ways to move an object without touching it and draw diagrams to show how forces are involved. 

Explore

Observations, Drawing Models, Written Responses:  

Students record written observations and draw models based on lab activities and computer simulations. 

In Part 1, students conduct a pre-lab in which they review all the procedures for three different labs. In Part 2, students conduct three labs. In the first lab, students focus on electrostatic force. After this lab, the whole class works with a simulation that models electrostatic force. In the second lab, students focus on magnetic force. After the second lab, the whole class works with a simulation that models magnetic force. In the third lab, students focus on gravitational force. After the third lab, the whole class works with a simulation that models gravitational force. Students record their observations and draw diagrams to try to explain what they observe.   

Students should be able to

• Investigate different ways electrostatic, magnetic, and gravitational forces can move objects from a distance. Students will view simulations to explore how non-contact forces can be explained by fields that extend through space. 
• Draw diagrams showing how forces are involved when objects are moved without contact. 
• Think about similarities and differences among electrostatic, magnetic, and gravitational forces.

Explain

Reading, Group Discussion:

Students will read an article working with partners and triads. Students answer Reflection Questions in small groups and discuss responses as a class. 

In Part 1, students engage in the close-reading protocol and answer questions using the Listening Triads protocol about the article “Non-Contact Forces.”  Section 1 of the article covers electrostatic force. Section 2 covers magnetic force. Section 3 covers gravitational force. In Part 2, students complete a Venn diagram that shows similarities and differences among electrostatic, magnetic, and gravitational forces. 

Students should be able to 

• Complete a  close-reading protocol and answer questions using the Listening Triads protocol about the article “Non-Contact Forces.”  
• Explain how electrostatic, magnetic, and gravitational forces can move objects from a distance. Their explanations should include the concept that these forces can be explained by fields that extend through space. 
• Explain the variables that affect the strength of each of these non-contact forces. 
• Complete a Venn diagram that shows the similarities and differences between these three non-contact forces. 

Elaborate

Extending Understanding and Applying Learning to a New Context: Students apply their understanding of non-contact forces and design experiments related to electrostatic, magnetic, and gravitational forces. 

Students design experiments using non-contact forces. In the first experiment, they consider electrostatic force and distance. In the second experiment, they consider mass and magnetic force. In the third experiment, they consider magnetic force and distance. Finally, students complete a thought experiment about how they might use gravitational force to change the motion of an asteroid. 

Students should be able to 

• Design experiments to investigate how charge, mass, and distance relate to electrostatic and magnetic forces. 
• Design a thought experiment about how they might use gravitational force to change the motion of an asteroid. Students record observations and draw diagrams of what they observe. 

Evaluate

Discussion, Drawing Models, and Written Responses:

Students demonstrate their understanding and evaluate their knowledge of non-contact forces. They apply what they have learned about non-contact forces to the problem posed in the Culminating Project. 

In Part 1, students work individually, with a small group, and as a whole class to create a concept map to summarize what they have learned in Subunit 2. In Part 2, students work together to connect the concepts they have learned to the Culminating Project. They return to the situations described in the Evaluate lesson from Subunit 1. This time, they must use a non-contact force in their solution. 

Students should be able to 

• Work together as a class to build a class concept map related to the content covered in Subunit 2. 
• Show how a non-contact force could be used to prevent an asteroid from colliding with Earth.

Instructional Sequence

Assessment Types at
This Stage

Assessment Description

Learning Target

Engage

Observations: Students’ background knowledge about gravitational force and motion in the solar system can be assessed. 

Students are presented with an online calculator that allows them to determine the weight of a person on another planet or the moon. They observe a video of a simulation that shows the motion of asteroids in the solar system. 

Students should be able to 

• Determine what their weight would be on another planet or the moon. 
• Come up with an explanation of how mass is different from weight. 
• Make observations about the motion of objects in the solar system from a simulation video. 

Explore

Observations, Drawing Models, Written Responses:  

Students record written observations and draw models based on labs and computer simulations. 

In Part 1, students work with a simulation to see what happens when  Newton’s Cannon is fired such that the cannonball moves with different velocities. They then work with a simulation that models different objects in orbit. Students can observe Earth orbiting the sun, Earth with the moon in orbit, Earth and the moon orbiting the sun, the moon orbiting Earth, and a man-made satellite moving in orbit around Earth.

Students should be able to 

• Explore a simulation of the thought experiment, Newton’s Cannon, and think about how this might relate to Earth moving in orbit around the sun.
• Investigate how gravity, velocity, mass, and distance affect the path of an object in orbit around another object. Students consider how objects in the solar system would move if there was no gravitational force. 

Explain

Reading, Group Discussion:

Students read an article working with partners and triads. Students answer Reflection Questions in small groups and discuss responses as a class. 

Students engage in the close-reading protocol and answer questions, using the Listening Triads protocol, about the article “Gravitational Force and Motion in the Solar System.”

Students should be able to 

• Complete a  close-reading protocol and answer questions, using the Listening Triads protocol, about the article “Gravitational Force and Motion in the Solar System.” 
• Explain that gravity is a predominantly inward-pulling, attractive force that can keep smaller, less massive bodies in orbit around larger, more massive bodies. 
• Explain that the gravitational force of the sun causes the planets and other bodies to orbit around it, holding the solar system together. 
• Explain what would happen to the motion of bodies in the solar system if there were no gravitational force present. 

Elaborate

Extending Understanding and Applying Learning to a New Context: Students apply their understanding of gravitational force and motion in the solar system to the motion of the asteroid from the Culminating Project. 

Students read a passage about how the orbits of asteroids can be altered such that they intersect with Earth’s orbit. Students are then asked to draw a diagram that shows how the orbit of an asteroid and the orbit of Earth could intersect such that a collision occurs. They watch a simulation of an asteroid that makes a close approach to Earth. After viewing the simulation, students have an opportunity to revise their models.

Students should be able to 

• Draw a diagram that shows how the orbit of an asteroid can intersect with the orbit of Earth such that the two bodies collide. 
• Observe a simulation of the orbit of an asteroid that makes a close approach to Earth. 
• Revise the diagrams of intersecting orbits based on what was observed in the simulation. 

Evaluate

Using Models to Show Understanding; Obtaining, Evaluating, and Communicating Information:  Students demonstrate their understanding and evaluate their knowledge of forces and motion in the universe.

 

In Part 1, students work as a whole class to update the Driving Question board to summarize what they have learned in the subunit. In Part 2, students work together on the Group Culminating Project. They then work on the Individual Culminating Project.

Students should be able to 

• Work together as a class to build a class concept map related to the content covered in Subunit 3. 
• Apply their understanding of motion in the universe to write an article about how to prevent an asteroid from colliding with Earth. Individually, students consider and write up an alternative solution, using a different type of force from what was used in the group solution. 

See the Culminating Project rubrics for more information on how to assess the Culminating Project.

Desired Results

Overview

To create a plan to prevent a collision between an asteroid and Earth, students use investigations to consider the relationship between forces and motion. In Subunit 1, students gather evidence to support the concept that changes to an object’s motion depends on the sum of the forces acting on the object and the mass of the object. Students use contact forces to design a solution to a problem involving the motion of two objects on a path for collision: Earth and an asteroid. In Subunit 2, students ask questions and construct experiments to determine the factors that affect the strength of electrostatic, magnetic, and gravitational forces. Students return to the problem of an asteroid heading toward Earth, this time considering how a non-contact force might solve the problem. In Subunit 3, students develop a model to describe the role of gravity in the motions of objects within the solar system, including that of the asteroid and Earth. 

Project Tasks

Connections to the Culminating Project: Lift-Off: Determine how scientists name asteroids and decide on a name for the asteroid. Identify the possible dangers represented by an asteroid of this size hitting Earth.

Connections to the Culminating Project: Subunit 1: Explain how contact forces can be used to change the orbit of an asteroid.

Connections to the Culminating Project: Subunit 2: Model the ways non-contact forces can be used to change the orbit of an asteroid.

Connections to the Culminating Project: Subunit 3: Examine gravitational forces at work in the solar system and how these can help with changing the orbit of an asteroid.

Estimated length of project: 405 minutes

ESTABLISHED GOALS

MS-PS2-1. Apply Newton’s Third Law to design a solution to a problem involving the motion of two colliding objects. [Clarification Statement: Examples of practical problems could include the impact of collisions between two cars, between a car and stationary objects, and between a meteor and a space vehicle.] [Assessment Boundary: Assessment is limited to vertical or horizontal interactions in one dimension.]

MS-PS2-2. Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object. [Clarification Statement: Emphasis is on balanced (Newton’s First Law) and unbalanced forces in a system, qualitative comparisons of forces, mass and changes in motion (Newton’s Second Law), frame of reference, and specification of units.] [Assessment Boundary: Assessment is limited to forces and changes in motion in one-dimension in an inertial reference frame and to change in one variable at a time. Assessment does not include the use of trigonometry.]

MS-PS2-3. Ask questions about data to determine the factors that affect the strength of electric and magnetic forces. [Clarification Statement: Examples of devices that use electric and magnetic forces could include electromagnets, electric motors, or generators. Examples of data could include the effect of the number of turns of wire on the strength of an electromagnet, or the effect of increasing the number or strength of magnets on the speed of an electric motor.] [Assessment Boundary: Assessment about questions that require quantitative answers is limited to proportional reasoning and algebraic thinking.]

MS-PS2-4. Construct and present arguments using evidence to support the claim that gravitational interactions are attractive and depend on the masses of interacting objects. [Clarification Statement: Examples of evidence for arguments could include data generated from simulations or digital tools; and charts displaying mass, strength of interaction, distance from the Sun, and orbital periods of objects within the solar system.] [Assessment Boundary: Assessment does not include Newton’s Law of Gravitation or Kepler’s Laws.]

MS-PS2-5. Conduct an investigation and evaluate the experimental design to provide evidence that fields exist between objects exerting forces on each other even though the objects are not in contact. [Clarification Statement: Examples of this phenomenon could include the interactions of magnets, electrically-charged strips of tape, and electrically-charged pith balls. Examples of investigations could include first-hand experiences or simulations.] [Assessment Boundary: Assessment is limited to electric and magnetic fields, and limited to qualitative evidence for the existence of fields.]

MS-ESS1-2. Develop and use a model to describe the role of gravity in the motions within galaxies and the solar system. [Clarification Statement: Emphasis for the model is on gravity as the force that holds together the solar system and Milky Way galaxy and controls orbital motions within them. Examples of models can be physical (such as the analogy of distance along a football field or computer visualizations of elliptical orbits) or conceptual (such as mathematical proportions relative to the size of familiar objects such as students' school or state).] [Assessment Boundary: Assessment does not include Kepler’s Laws of orbital motion or the apparent retrograde motion of the planets as viewed from Earth.]

NGSS Lead States. 2013. Next Generation Science Standards: For States, By States. Washington, DC: The National Academies Press.

ESSENTIAL QUESTION

How can we change the motion of an asteroid heading toward Earth?

Students will be able to independently use their learning to

• Apply their understanding of contact forces to the asteroid problem.
• Apply their understanding of non-contact forces to the asteroid problem.
• Apply their understanding of gravitational forces in the solar system to the asteroid problem.

Students will know 

• How to apply Newton’s Third Law to design a solution to a problem involving the motion of two colliding objects. 
• That the change in an object’s motion depends on the sum of the forces on the object and the mass of the object.
• About data to determine the factors that affect the strength of electric and magnetic forces. 
• That gravitational interactions are attractive and depend on the masses of interacting objects.
• That fields exist between objects exerting forces on each other even though the objects are not in contact.
• The role of gravity in the motions within galaxies and the solar system.

Evidence

Assessment Evidence

PERFORMANCE TASK: Create a plan to change the orbit of an asteroid to avoid collision with Earth.

At the end of this unit, students write a news report about their proposal to protect Earth from an asteroid impact. These news reports are based on students’ understanding of motion, contact and non-contact forces, and gravitational forces in the solar system. In the Individual Culminating Project, students propose alternative solutions to the one their groups suggest. 

Articles include two main sections.

1. An explanation of the danger of an asteroid impact with Earth.
   1. Name the asteroid, based on research into how asteroids are named in the scientific community.
   2. Explain what could happen on land and in water if a large asteroid collided with Earth.
2. A proposed plan of action to address the problem.
   1. Choose either a contact force or non-contact force.
   2. Include an explanation of how the force will be applied.
   3. Explain how Newton’s laws of motion relate to changing the motion of the asteroid.
   4. Include a diagram that 
      • Shows how the orbit of the asteroid could intersect with Earth’s orbit in a way that causes a collision. 
      • Includes arrows that indicate the gravitational forces responsible for keeping the asteroid and Earth in orbit around the sun.
      • Shows the magnitude and direction of the force used to change the motion of the asteroid. 
   5. Explain how your solution helps avoid the collision.

Individual Culminating Project: An alternative plan of action.

In addition to the Group Culminating Project, students work on an Individual Culminating Project. Individual students provide an alternative solution to preventing an asteroid from colliding with Earth. The alternative must use a different type of force than the one used in the Group Culminating Project. If the Group Culminating Project uses a contact force to solve the problem, then the Individual Culminating Project must use a non-contact force. If the Group Culminating Project uses a non-contact force to solve the problem, then the Individual Culminating Project must use a contact force. 

The solution must

1. Use either a contact force or non-contact force to solve the problem and explain how this will alter the motion of the asteroid. 
2. Explain how to apply this force.
3. Explain how Newton’s laws of motion relate to changing the motion of the asteroid.
4. Include a diagram that  
   1. Shows how the orbit of the asteroid could intersect with Earth’s orbit in a way that causes a collision. 
   2. Includes arrows that indicate the gravitational forces responsible for keeping the asteroid and Earth in orbit around the sun.
   3. shows the magnitude and direction of the force used to change the motion of the asteroid. 
5. Explain how the solution helps to avoid the collision.

Learning Plan

Subunit 1: How can we change the motion of an object by using a contact force? 

In this subunit, students explore the concept that the motion of an object is determined by the sum of the forces acting on it. Students learn that if the net force on the object is not zero, its motion will change. Students also learn that the greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion. For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction. Students apply what they learn to come up with a solution to change the motion of an asteroid using a contact force. 

Subunit 2: How can we change the motion of an object by using a non-contact force?

In this subunit, students explore non-contact forces, including electrostatic, magnetic, and gravitational force. Students learn that these forces act at a distance and can be explained by fields that extend through space. Students investigate how electrostatic and magnetic forces can be attractive or repulsive and that their sizes depend on the magnitudes of the charges or magnetic strengths involved as well as the distances between the interacting objects. Students investigate how gravitational forces are always attractive. There is a gravitational force between any two masses, but it is very small except when one or both of the objects have a large mass. 

Subunit 3: How does gravitational force affect the motion of objects in the solar system?

In this subunit, students continue to explore gravitational force. Students investigate how the solar system consists of the sun and a collection of objects, including planets, their moons, and asteroids. These bodies are all held in orbit around the sun by its gravitational pull on them. 

Unit Map

Motion in the Universe

Essential Question: How can we change the motion of an asteroid heading toward Earth?

Lift-Off and Introduction to the Culminating Project

 Subunit 1: Contact Forces

How can we change the motion of an object by using a contact force?

Engage • Explore 1 • Explain 1 • Explore 2 • Explain 2 • Explore 3 • Explain 3 • Elaborate • Evaluate

Subunit 2: Non-Contact Forces

How can we change the motion of an object by using a non-contact force?

Engage • Explore • Explain • Elaborate • Evaluate

Subunit 3: Gravitational Force in the Solar System

How does gravitational force affect the motion of objects in the solar system?

Engage • Explore • Explain • Elaborate • Evaluate

Group Culminating Project

Prevent Asteroid Collision with Earth

Individual Culminating Project

Alternative Solution to Prevent an Asteroid Collision

Course Concepts

+ Foundational Crosscutting Concepts: These concepts are foundational to the understanding of middle school science. These concepts are present throughout the course. Students are expected to continue to apply their knowledge of the concepts to subsequent relevant projects. 

* Focal Crosscutting Concept: This concept is called out consistently in the Teacher Book and once per subunit in the Student Book. Students will consider the unit project through the lens of this crosscutting concept. 

Crosscutting Concept

Unit 1: Motion in the Universe

Unit 2: Waves

Unit 3: Life on Earth

Unit 4: Natural Selection

Patterns

+

+

*

Cause and Effect

+

*

+

+

Scale, Proportion, and Quantity

+

+

Systems and Systems Models

*

Energy and Matter

Structure and Function

+

*

Stability and Change

+

Science and Engineering Practices 

+ Foundational Science and Engineering Practices: These practices “carry forward” through the course. Students focus on one of these practices per unit and are expected to continue to apply that knowledge to subsequent relevant projects. 

* Focal Science and Engineering Practice: This practice is called out consistently in the Teacher Book and once per subunit in the Student Book. Students will use this practice to complete the unit project. 

Science and Engineering 

Practices

Unit 1: Motion in the Universe

Unit 2: Waves

Unit 3: Life on Earth

Unit 4: Natural Selection

Asking Questions and Defining Problems 

*

+

+

Developing and Using Models 

+

*

+

Planning and Carrying Out Investigations 

+

Analyzing and Interpreting data

+

Using Mathematics and Computational Thinking

+

*

Constructing Explanations and Designing Solutions

+

+

Engaging in Argument from Evidence

+

*

Obtaining, Evaluating and Communicating Information

+

+

MS-PS2-1

Apply Newton’s Third Law to design a solution to a problem involving the motion of two colliding objects. [Clarification Statement: Examples of practical problems could include the impact of collisions between two cars, between a car and stationary objects, and between a meteor and a space vehicle.] [Assessment Boundary: Assessment is limited to vertical or horizontal interactions in one dimension.]

MS-PS2-2

Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object. [Clarification Statement: Emphasis is on balanced (Newton’s First Law) and unbalanced forces in a system, qualitative comparisons of forces, mass and changes in motion (Newton’s Second Law), frame of reference, and specification of units.] [Assessment Boundary: Assessment is limited to forces and changes in motion in one-dimension in an inertial reference frame and to change in one variable at a time. Assessment does not include the use of trigonometry.]

MS-PS2-3

Ask questions about data to determine the factors that affect the strength of electric and magnetic forces. [Clarification Statement: Examples of devices that use electric and magnetic forces could include electromagnets, electric motors, or generators. Examples of data could include the effect of the number of turns of wire on the strength of an electromagnet, or the effect of increasing the number or strength of magnets on the speed of an electric motor.] [Assessment Boundary: Assessment about questions that require quantitative answers is limited to proportional reasoning and algebraic thinking.]

MS-PS2-4 

Construct and present arguments using evidence to support the claim that gravitational interactions are attractive and depend on the masses of interacting objects. [Clarification Statement: Examples of evidence for arguments could include data generated from simulations or digital tools; and charts displaying mass, strength of interaction, distance from the Sun, and orbital periods of objects within the solar system.] [Assessment Boundary: Assessment does not include Newton’s Law of Gravitation or Kepler’s Laws.]

MS-PS2-5

Conduct an investigation and evaluate the experimental design to provide evidence that fields exist between objects exerting forces on each other even though the objects are not in contact. [Clarification Statement: Examples of this phenomenon could include the interactions of magnets, electrically-charged strips of tape, and electrically-charged pith balls. Examples of investigations could include first-hand experiences or simulations.] [Assessment Boundary: Assessment is limited to electric and magnetic fields, and limited to qualitative evidence for the existence of fields.]

MS-ESS1-2 

Develop and use a model to describe the role of gravity in the motions within galaxies and the solar system. [Clarification Statement: Emphasis for the model is on gravity as the force that holds together the solar system and Milky Way galaxy and controls orbital motions within them. Examples of models can be physical (such as the analogy of distance along a football field or computer visualizations of elliptical orbits) or conceptual (such as mathematical proportions relative to the size of familiar objects such as students' school or state).] [Assessment Boundary: Assessment does not include Kepler’s Laws of orbital motion or the apparent retrograde motion of the planets as viewed from Earth.]

Misconceptions 

Accurate Concepts

The only way to protect Earth from the impact of a near-Earth object (NEO) would be to use a nuclear weapon to break the NEO up into pieces.

Adapted from:

NASA Planetary Defense FAQ (https://www.nasa.gov/planetarydefense/faq)

Breaking up or deflecting an asteroid with a nuclear weapon is not the only possible technique that scientists are studying in order to protect Earth from a collision. Any method chosen would depend on when an asteroid is found and how much time we have to put a solution in place. The choice of method for impact mitigation depends on the orbit of the object and its composition, bulk properties, and relative velocity, as well as the probability of impact and the predicted impact location.  Some NEOs could be in orbits that are especially hard to reach unless we find them many years to decades in advance of impact. Some asteroids are essentially rubble piles, making them difficult to “push on” without breaking them up, while others could be coherent monolithic bodies. There are many unknowns related to using a nuclear weapon to break up an asteroid. There may be issues with timing and the rotational motion of the asteroid. It may not work as well with a rubble pile. As well, it may be possible to deflect the asteroid by detonating an explosive near, but not on, the asteroid. So it may not be necessary to blow it up into smaller pieces. 

According to NASA, the key to preventing an impact is to find any potential threat as early as possible. With a couple of decades of warning, which would be possible for 100-meter-sized asteroids with a more capable detection network, several options are technically feasible for preventing an asteroid impact. Deflecting an asteroid that is on an impact course with Earth requires changing the velocity of the object by less than an inch per second years in advance of the predicted impact. The two most promising techniques that NASA is investigating are the kinetic impactor (hitting an asteroid with an object to slightly slow it down) and the gravity tractor (gravitationally tugging on an asteroid by station-keeping a large mass near it). An asteroid on a trajectory to impact Earth could not be shot down in the last few minutes or even hours before impact. In minutes or hours before impact, no known weapon system could stop the mass because of the velocity at which it travels—an average of 12 miles per second. 

Talbert, Tricia. “Planetary Defense Frequently Asked Questions.” NASA. NASA, December 29, 2015. https://www.nasa.gov/planetarydefense/faq.

Misconceptions 

Accurate Concepts

A constant force is needed to keep an object moving at constant speed. 

From American Association for the Advancement of Science (AAAS) Misconceptions (http://assessment.aaas.org/misconceptions/1/FMM129/260)

An object in motion will remain in motion (with a constant speed and direction), and an object at rest will remain at rest unless acted upon by an outside force.

A moving object has a force within it that keeps it moving. (McCloskey, 1983; Osborne, 1985; Viennot, 1979).

From AAAS Misconceptions (http://assessment.aaas.org/misconceptions/1/FMM090/259)

The initial motion of an object is determined by the sum of the forces acting upon it. An object’s motion will change only if the sum of the forces acting upon it are unbalanced. Objects with greater mass require greater force to change motion. For an object of unchanging mass, a larger force will result in a larger change in motion.

Only living things can exert force. 

Living and nonliving objects can exert force on another living or nonliving object. 

Newton’s third law forces do not occur simultaneously. An “action” force causes a “reaction” force to occur a moment later.

PS2.A: Forces and Motion

For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction. These forces occur simultaneously. 

Misconceptions 

Accurate Concepts

An object has to touch another object for a force to be exerted.

Students may confuse gravitational and magnetic forces. 

Magnets only attract. 

PS2.B: Types of Interactions

Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distances between the interacting objects. Gravitational forces are always attractive. There is a gravitational force between any two masses, but it is very small except when one or both of the objects are large—for example, Earth and the sun.

Misconception 

Accurate Concept

Students may confuse gravitational and magnetic forces. 

PS2.B: Types of Interactions

Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distances between the interacting objects. Gravitational forces are always attractive. There is a gravitational force between any two masses, but it is very small except when one or both of the objects have large mass—for example, Earth and the sun.

There is no gravity in space.

ESS1.B:  Earth and the Solar System

The solar system consists of the sun and a collection of objects, including planets, their moons, and asteroids that are held in orbit around the sun by its gravitational pull on them. The solar system appears to have formed from a disk of dust and gas, drawn together by gravity. See also 

Only Earth experiences a gravitational pull.

ESS1.B:  Earth and the Solar System

The solar system consists of the sun and a collection of objects, including planets, their moons, and asteroids that are held in orbit around the sun by its gravitational pull on them. The solar system appears to have formed from a disk of dust and gas, drawn together by gravity. 

Permanent

Consumable

Teacher Provided

• Die or nonmagnetic cube (8)
• Small (1”) ceramic disc magnet (32)
• 1-ft. length of string (8)
• 1¼” binder clip (8)
• Plastic drinking straw (8)
• Small paper clips (16)
• ¾” steel ball bearings (16)
• Bar magnets with N/S poles labeled (16)
• Iron filings (4 tsp)
• Resealable sandwich bag (16)
• 3”x5” index card (8)
• Golf ball (8)
• Ping pong ball (8)
• 50x6x6 mm cobalt steel bar magnet (8)
• 12” ruler (8)
• 16 oz. plastic cups (24)

• Paper drinking straw (40)
• Cotton String (~400 ft.)
• Balloon (200)

• Chart paper (5)
• Sheet of paper (1)
• Pen or pencil (8)
• Coin (1)
• Chair on wheels or skateboard (1)
• Classroom chairs to serve as anchors (2)
• Sheets of paper (used ok)(20)
• Strips (~2”x12”) aluminum foil (80)
• Timer or cellphone timer (8)
• Letter-size paper (used ok) (40) 
• Tap water ( 5 L)
• Transparent tape (~50 ft.)
• Masking tape (~20 ft.)
• Duct tape (1 roll)