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8-GA-MS-3.c – Inertia: Heavier Object Require More Force to Accelerate

GRADE: Middle (6-8), 8  |  TIME: 7-10 Days

OVERVIEW

Students will further evaluate factors that affect the motion of an object. In this lesson, students will analyze the relationship between the force, mass, and acceleration. The primary focus of this lesson will be the relationship between force and mass in the context of causing an object to accelerate. This lesson is a continuation of the S8P3.a and S8P3.b with a narrowed focus that relates Newton’s 1st and 2nd Law to the motion of an object.

DISCIPLINE: Physical Sciences
TOPIC: Forces and Interactions, Forces and Interactions: Pushes and Pulls, Physical Science
GA STANDARDS(GSES): Georgia Standards of Excellence (GSE) DRAFT, S8P3. Force, Mass, and the Motion of Objects
NGSS CORE IDEA: PS2 Motion and Stability: Forces and Interactions, PS2.A Forces and Motion
PRACTICE: Planning & Carrying Out Investigations
CROSSCUTTING CONCEPTS: Stability and Change

Standards

Georgia Standards of Excellence in Science (GSES):

S8P3. Obtain, evaluate, and communicate information about cause and effect relationships between force, mass, and the motion of objects.  

c.  Construct an argument from evidence to support the claim that heavier objects require a greater force to accelerate.

NGSS Standard:

Performance Expectation(s)

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. (MS-PS2-2)

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.

Science and Engineering Practice(s)

Planning and Carrying Out Investigations

Planning and carrying out investigations to answer questions or test solutions to problems in 6–8 builds on K–5 experiences and progresses to include investigations that use multiple variables and provide evidence to support explanations or design solutions.

Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim.

Disciplinary Core Idea(s)

  1. A: Forces and Motion

The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. 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. (MS-PS2-2)

All positions of objects and the directions of forces and motions must be described in an arbitrarily chosen reference frame and arbitrarily chosen units of size. In order to share information with other people, these choices must also be shared. (MS-PS2-2)

Crosscutting Concept(s)

Stability and Change

Explanations of stability and change in natural or designed systems can be constructed by examining the changes over time and forces at different scales.

NGSS Evidence Statement:

 

1.      Identifying the phenomenon to be investigated

 a.      Students identify the phenomenon under investigation, which includes the change in motion of an object.

 b.      Students identify the purpose of the investigation, which includes providing evidence that the change in an object’s motion is due to the following factors:

i.           Balanced or unbalanced forces acting on the object

ii.         The mass of the object.

 

2.  Identifying the evidence to address the purpose of the investigation

 

a.      Students develop a plan for the investigation individually or collaboratively. In the plan, students describe*:


i.           That the following data will be collected

1.      Data on the motion of the object.
2.      Data on the total forces acting on the object.
3.      Data on the mass of the object


ii.         Which data are needed to provide evidence for each of the following:


1.      An object subjected to balanced forces does not change its motions (Sum of F = 0)
2.      An object subjected to unbalanced forces changes its motion over time (sum of F≠0).
3.      The change in the motion of an object subjected to unbalanced forces depends on the mass of the object.

 

a. In the investigation plan, students describe*:

i.      How the following factors will be determined and measured:

1. The motion of the object, including a specified reference frame and appropriate units for distance and time.

2.   The mass of the object, including appropriate units.

3.   The forces acting on the object, including balanced and unbalanced forces.

ii.      Which factors will serve as independent and dependent variables in the investigation (e.g., mass is an independent variable, forces and motion can be independent or dependent).

iii.     The controls for each experimental condition.

iv.     The number of trials for each experimental condition.

Other Standards:

Framework

Overview

Students will further evaluate factors that affect the motion of an object.  In this lesson, students will analyze the relationship between the force, mass, and acceleration.  The primary focus of this lesson will be the relationship between force and mass in the context of causing an object to accelerate.  This lesson is a continuation of the S8P3.a and S8P3.b with a narrowed focus that relates Newton’s 1st and 2nd Law to the motion of an object.

 

Elicit Questions:

What is acceleration?

What is inertia and what variable is related to?

What is the relationship between force, mass, and acceleration?

 

Engage: Students will watch a demo using a penny, plastic cup, and index card to evaluate the law of inertia.  Students will follow this by doing the demo themselves and writing down their observations.

 

Explore:  Students will do a lab to evaluate the relationship between force, mass, and acceleration.  To understand this relationship students must describe inertia (mass), force, and acceleration.

 

Engineer: Students will build a water rocket and use Newton’s Laws to properly engineer the rocket.

 

Explain:   Students will go through an interactive Power Point to analyze the relationship between force, mass, and acceleration.

 

Environmental Stewardship: Students will research electric cars and compare them to gas cars using the following criteria:  Environmental, Economic, and Performance.  Students will produce a pamphlet, newsletter, or other media for the public to act as an informative piece.

 

Evaluate: A self-assessment will be provided before the unit starts and after the unit is completed.  Students will also do a Kahoot quiz.  The engineer tab rubric will act as a summative assessment.

G-R-C

Gather:

Identify the science and engineering practices (copy/paste from list below) students will use to gather information about a phenomenon or problem raised in the ENGAGE section. Gathering includes any of the following:

  • Obtaining Information
  • Asking Questions/Defining Problems
  • Planning & Carrying Out Investigations
  • Using Models to Gather Data
  • Using Mathematics/Computational Thinking

 

Reason:

Identify the science and engineering practices (copy/paste from list below) students will use to reason and make sense of information gathered about a phenomenon or a problem. Reasoning includes any of the following:

  • Evaluating Information
  • Analyzing Data
  • Using Mathematics/Computational Thinking
  • Developing Evidence
  • Constructing Explanations/Solving Problems
  • Using Models to Predict & Develop Evidence

 

Communicate:

Identify the science and engineering practices (copy/paste from list below) students will use to communicate information and/or evidence. Communicating includes any of the following:

  • Communicating Information
  • Arguing from Evidence (written & oral)

• Using Models to Communicate

Engineer

(90 – 120 Minutes)

Water Rocket Lab Handout
Water Rocket Rubric
Lesson Focus

Lesson focuses on aerospace engineering and how space flight has been achieved from an engineering vantage point. Student teams build and launch a rocket made out of a soda bottle and powered with an air pump and consider the forces on a rocket, Newton’s Laws, and other principles and challenges of actual space vehicle launch. Teams design their structure on paper, learn about aerospace engineering, launch their rocket, and share observations with their class.

 

Lesson Activities

Students explore how engineers have developed rockets over the years, and learn about the principals of rocketry. They work in teams to construct and launch a rocket made from a soda bottle that launches with an air pump under teacher supervision. The students compare their accomplishments and challenges with those of other student teams, complete a reflection sheet, and present to the class.

Engage

(20-30 Minutes)

Inertia Handout
Newton’s (Sir Isaac Newton, English physicist, 1642–1727) First Law of Motion states that: “An object at rest tends to stay at rest, and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.” The tendency of objects to resist changes to their state of motion is known as inertia. Sir Isaac Newton’s ideas about inertia were directly opposed to more popular conceptions about motion. Before Newton, it was believed that the natural tendency of objects was to come to a rest position. It was thought that objects in motion would eventually stop moving and that a force was necessary to keep an object in motion. In this activity, you will demonstrate the concept of inertia.

 

Directions: Teacher will model demo.  Students will repeat demo by placing the index card on top of the cup.  Students will then place a penny on top of the card.  Students will snatch the card and observer the law of inertia.

Elicit Questions

Essential Questions:

What is acceleration?

What is inertia and what variable is related to?

 

Driving Question:

What is the relationship between force, mass, and acceleration?

Explain

(45 – 60 Minutes)

Forces, Inertia, and Motion Power Point
Students will use the Power Point chart titled “Forces, Inertia, and Motion” S8P3.c”.  Teacher will assist students in making connections between the toy car lab and the concepts related to Newton’s 1st two laws.

Evaluate

(15 – 25 Minutes)

Formative Assessment: Kahoot Quiz found here:  https://play.kahoot.it/#/k/fe415c76-7d5a-4045-bfff-0e90bebc1c0d

Summative Assessment:  The Water Rocket Rubric for the Engineering project will be used as a summative assessment for this lesson.

 

Explore

(45-60 Minutes)

Force Acceleration Lab Handout
Students will do a lab that using a car, masses, and stopwatches..

Purpose:
Students will experiment with factors that affect the acceleration of a toy car.

Concept:
Newton’s 1st Law is the Law of Inertia, Newton’s 2nd Law of Motion, Relationship between force, mass, and acceleration.

Procedure (See Handout):

  1. Tie one end of the string to the paper clip. Tie the other end to the toy car.
  2. Place your car on the table and hang the paper-clip hook over the edge of the table.
  3. You have been given several different weights. Use the triple beam balance to find the mass of each weight. Record this information.
  4. Predict how the car will move as the different weights are hung from the paper-clip hook and allowed to fall to the floor. Record your predictions in the data section.
  5. Conduct your investigation, and then record your observations.

Extend

(60 – 75 Minutes)

Collision on the Tracks Lab Extension
Purpose:

Students will examine Newton’s Second Law of Motion by investigating the relationships between force, mass, and acceleration.

Overview of Procedure:

Students will use the textbooks to adjust the angle of the ramp.  They will use the marbles in one set of trials to test the cause and effect relationship between mass and acceleration when the force is constant.  In another set of trials they will use marbles with equal masses to test the cause and effect relationship between force and acceleration when mass is constant.

Supplies and Prep

Elicit Questions:
  • 1 Board/Poster for posting questions.
Engage:
  • Materials (1 of Each per 1-3 Students):
  1. Inertia Handout
  2. Plastic Cup
  3. Note card
  4. Penny
Explore:
  1. 60 cm string
  2. Weights
  3. Toy car
  4. Paper clips
  5. Stopwatches
  6. Triple Beam or Electronic Balance
  • Preparation
  1. Cut the string in advance and package the small materials in plastic baggies (paper clips, string, and weights). You can use one balance for every 4-6 students (they can share even if they are not working directly together).  Every group will need a stopwatch, car, and baggie with materials.
Engineer:
  • Water Rocket Lab Handout(teacher and student)
  • Materials (Per Team): 1  of each Empty soda bottle (2 Liter), cork, paper, pen, pencil; plastic tubing, bicycle tire valve, cardboard, glue, tape, rubber bands, foil, decoration materials (i.e. construction paper, markers, paints, etc.)
  • Materials for everyone to share: Water source, drill (if not using a kit), bicycle tire pump
  • Water Rocket Rubric
  • Preparation:
  1. Have students read pages 6-12 prior to starting the project.
  2. Group students and collect materials prior to starting the project.
  3. Use pages 13-18 as the questions and the written portion of the activity.
Explain: Environmental Stewardship Project: Evaluate:
  • Kahoot Quiz: Computer, Projector, and electronic device for every student.
  • Summative Assessment: Water Bottle Rocket Rubric
Extend:
  • Collision on the Tracks
  1. Collision on the Tracks Lab Extension: 1 per group (2-3 students)
  • Materials per Group
  1. Three Marbles (different masses)
  2. 1 meter track (hot wheels or tube)
  3. 1 meter stick
  4. Textbooks or flat even objects for stacking to adjust the ramp size.
Group Lesson:
  • Phet Forces and Motion: 
  1. PhET - Forces Motion Basics Handout
  2. Computer or Tablet
  3. Internet Connection
Individual Lesson:
  • Graphic Organizers:   
  1. Relationship 1:  Mass & Inertia Graphic Organizer 
  2.  Relationship 2: Mass and Velocity Graphic Organizer
 

Environmental Stewardship

(90-120 Minutes)

Gas Electric Comparison Handout (For Research Purposes)
Students will use the handout and the website with the directions and all required videos. http://www.pbs.org/wgbh/nova/education/activities/3507_car.html

Activity Summary
Student teams research and develop a proposal to decrease the carbon footprint of their city’s public transportation system through the use of various new technologies and/or alternative fuels. Students prepare a report that explains why their transportation plan is the best one for their community.

Learning Objectives
Students will be able to:

  • Understand the pros and cons of adopting new technologies or alternative fuels to replace existing gasoline-powered vehicles.

Describe the environmental impact of alternative fuels.

STEM Connections

Science – Study of the relationship between force, mass, and acceleration (Newton’s 1st and 2nd Law)

Technology – Use of internet to research information and to create a presentation/video for the teacher and peers.

Engineering – Using lab materials to set up an apparatus to test the relationship between force, mass, and acceleration. (See Explore), Designing a Water Rocket for maximum efficiency.

Math – Collecting data, graphing data, and analyzing data.

Student Handouts

Engage:

  1. Inertia Handout: This handout provides background, the demo directions (with images), and follow up questions.

Explore:

  1. Force Acceleration Lab Handout: Handout with directions, questions, a table, graphing grid, and space to answer questions throughout.

Engineer:

  1. Water Rocket Lab Handout: Handout includes lesson plans and preparation for the teacher followed by informational text and student handouts.
  2. Water Rocket Rubric: This handout outlines the expectations for the water rocket which should act as a summative assessment. 

Environmental Stewardship: 

  1. Gas Electric Comparison Handout (For Research Purposes): Handout for students to give basic information to start the project.

Evaluate:

  1. Water Rocket Rubric: This handout outlines the expectations for the water rocket which should act as a summative assessment.

Extend:

  1. Collision on the Tracks Lab Extension: This handout gives directions that are sectioned off.   For each section there are illustrations, tables for data, directions, and follow up questions.  You can use one or all the sections.  I advise doing at least the first two sections of the lab.

Group Activity:

  1. PhET – Forces Motion Basics Handout: This handout provides directions for the interactive simulation.  There are directions on how to use the Phet simulations as well as space to document answers and observations.

Individual Activity:

  1. Mass & Inertia Graphic Organizer: This handout uses if/then statements to support student understanding of the relationship between mass and inertia.  There is space to write explanations.
  2. Mass and Velocity Graphic Organizer: This handout uses if/then statements to support student understanding of the inversely proportional relationship between mass and velocity with a constant applied to force.  There is space to write explanations.

ReTeach

Small Group Learning Activity:

 (60 Minutes)

PhET – Forces Motion Basics Handout
Force and Motion Basics:  This simulation can be found here: https://phet.colorado.edu/sims/html/forces-and-motion-basics/latest/forces-and-motion-basics_en.html.  Students will use the following simulation to evaluate the relationship between force, mass, and acceleration.  Students will use the motion and acceleration setting of the simulation to complete guided, interactive inquiry.


Individual Learning Activity:

(30 – 45 Minutes)

Mass & Inertia Graphic Organizer
Mass and Velocity Graphic Organizer
Students will use two different graphic organizers that evaluate the relationship between mass and inertia as well as mass and velocity (or a change in velocity).  The graphic organizers use the if/then format to identify these relationships.  This is followed by an explanation and then a summary. This is very similar to the Claim Evidence Reasoning model (CER).  The claim is the if/then, the evidence is the “because”, and the summary is the reasoning.  This allows students to document their understanding by tying content to real world phenomenon.

Teaching Tips

Students must be able to first analyze, compare, and contrast velocity, speed, acceleration, and distance using data to be able to proficiently communicate about the motion of objects (S8P3.a). This should be followed by an understanding of the effect of balanced and unbalanced forces on the motion of these objects (S8P3.b).  Students may think that unbalanced forces cause objects to have velocity but this is a misconception.  Unbalanced forces cause object to change speed (i.e. accelerate) and an object can be moving at a constant speed with balanced forces (net force = 0) acting on it.  This lesson helps students evaluate the effect of mass on the acceleration of the objects.  Additionally, students must understand that inertia is related to mass and that objects with greater masses have greater inertia and require greater forces to accelerate (S8P3.c).  This is the natural progression that should be used to build strong foundational knowledge about mechanics and dynamics (forces and motion).

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