Investigating Newton's Second Law-Mass and Accelaration

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Objective

SWBAT explain how mass of an object affects the distance the object moves.

Big Idea

Students will create a ramp to test varying amounts of mass to determine if the distance a car travels will increase as the mass of the car increases.

Lesson Overview

5e Lesson Plan Model

Many of my science lessons are based upon and taught using the 5E lesson plan model: Engage, Explore, Explain, Elaborate, and Evaluate. This lesson plan model allows me to incorporate a variety of learning opportunities and strategies for students.  With multiple learning experiences, students can gain new ideas, demonstrate thinking, draw conclusions, develop critical thinking skills, and interact with peers through discussions and hands-on activities.  With each stage in this lesson model, I select strategies that will serve students best for the concepts and content being delivered to them.  These strategies were selected for this lesson to facilitate peer discussions, participation in a group activity, reflective learning practices, and accountability for learning.

Unit Focus  

The Forces and Motions unit focuses on gravity exerted by Earth on objects, while at rest or during motion. With this in mind, students will investigate types of forces and the effects it has on moving objects. They learn how forces can stop an object from moving, increase or decrease the speed of an object moving, change its direction, and put a resting object into motion. Through models, investigations, research, and the engineering and design process, students learn that gravity is a constant force that impacts an object’s motion. The unit wraps up with students using the engineering and design process to create a zip line to illustrate the effects of gravitational force.

Lesson Synopsis

In this lesson, Newton's Second Law of Motion-Mass and Acceleration, I begin with a demonstration, letting 2 objects go down a ramp. I have students observe and share what they notice. Then I review relevant vocabulary terms for this law of motion that they will need to understand for the investigation. Once we develop our vocabulary background, students take part in an investigation to test the mass of an object during acceleration. They complete three trials and track each one in a data table. They use their data to draw conclusions about Newton's Second Law of Motion and create a line graph to visually see the changes in acceleration with increased mass. They reflect on this graph using a paragraph frame to help them structure their thinking and understanding. 

Next Generation Science Standards  

This lesson will address and support future lessons on the following NGSS Standard(s):

5-PS2-1.  Support an argument that the gravitational force exerted by Earth on objects is directed down.

Scientific & Engineering Practices

Students are engaged in the following scientific and engineering practices:

3.) Planning and Carrying Out An Investigation- Students conduct an investigation to produce evidence of Newton's Second Law of Motion and use their understanding to graph the changes that occurred. 

Crosscutting Concepts

The Newton's Second Law of Motion-Inertia lesson will correlate to other interdisciplinary areas.  These Crosscutting Concepts include:

2.) Cause and Effect- Students conduct an investigation to determine how mass affect acceleration. They use their observations to understand the effects of Newton's Second Law of Motion.

Disciplinary Core Ideas

Disciplinary Core Ideas within this lesson include:

PS2.A - Forces and Motion

PS2.B-  Types of Interactions

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Classroom Management Methods

Importance of Modeling to Develop Student

Responsibility, Accountability, and Independence 

Depending upon the time of year, this lesson is taught, teachers should consider modeling how groups should work together; establish group norms for activities, class discussions, and partner talks.  In addition, it is important to model think aloud strategies.  This sets up students to be more expressive and develop thinking skills during an activity.  The first half of the year, I model what group work and/or talks “look like and sound like.”  I intervene the moment students are off task with reminders and redirection.  By the second and last half of the year, I am able to ask students, “Who can give of three reminders for group activities to be successful?” Who can tell us two reminders for partner talks?”  Students take responsibility for becoming successful learners.  Again before teaching this lesson, consider the time of year, it may be necessary to do a lot of front loading to get students to eventually become more independent and transition through the lessons in a timely manner.

  • EXPLORE TEAMS (Pre-Set)

For time management purposes, I use “lab rats ” where each student has a number on the back of his or her chair, 1,2,3,4 (students sit in groups of 4)and displayed on the board.  For each activity I use lab rats, I switch up the roles randomly so students are experiencing different task responsibilities which include:  Director, Materials Manager, Reporter, and Technician.  It makes for smooth transitions and efficiency for set up, work, and clean-up.  

Engage

15 minutes

Initiating Curiosity

First, I hand out white boards and explain to students that they are going to observe me as I roll a large beach ball and tennis ball down a ramp. (The large ball is lighter than the tennis ball.  I do this purposefully because I want students to recognize that just because an object is larger, does not mean it has more mass.)  

After a few rolls, I ask them to think and write an observation on their whiteboard. When they finish, I have them turn and talk with their group members to discuss what they noticed. Then I ask groups to summarize their discussion by sharing their observations.   I am looking for students to come to the conclusion that one ball moved faster and farther than the other ball.

Then I ask: "When something moves faster, is there a word we could use to describe how quick that motion is?"  I am looking for the word accelerate but I know this may be a stretch if they are unfamiliar with the term. After students share their ideas, I write the word accelerate on the board and direct their attention to the studyjams video on Newton's 2nd law of motion- mass and acceleration  I have projected.

Vocabulary Preview

After the video, I hand out a new Newton's laws vocabulary graphic organizer and explain we are using this to keep track of key words related to Newton's 2nd law of motion-mass and acceleration like we used in yesterday's lesson on the Law of Inertia.

I point out the key words students should recognize in relation to this law of motion- acceleration, speed, velocity, and deceleration.

Then, I locate the Law of Mass and Acceleration in the video and pause it so students can record a description at the top of their handout: acceleration is produced when a force acts upon an object. The more mass an object has the more force needed to move or accelerate the object.

Now we take a closer look at the terms accelerate, velocity, and deceleration. As we review each of these terms, I note them on the board as they write them on their graphic organizer.

  • acceleration- the rate at which speed and velocity of an object change over time
  • speed measurement of how fast an object moves from one place to another
  • velocity – speed and direction.
  • deceleration- diminishing of speed, objects in motion slow down

 

I tell them to keep this organizer out to use as a reference sheet as they continue their investigation on this law of motion.

Explore / Explain

30 minutes

Investigation

Now that students have been exposed to some vocabulary, I tell them that they are going to explore Newton's Law of Mass and Acceleration by taking part in a ramp race activity.

Using our lab rats roles, I hand out a task card and data table, then ask students to set up their interactive notebook. Once our notebooks are set up, the lab rats' material manager retrieves the materials tray (1 m long board, 10-12 metal washers, toy car, digital scale, and meter tape) and I review how they are being used as I go over the directions.

The overall task is to set up a ramp, roll the toy car down it, and measure (in cm) how far it travels once it leaves the ramp and how long it takes from start to finish. Students complete three trials of this (for accuracy) and find the average distance. Then they complete two more tests with increased mass; they add five washers for the second round and 10 for the third.  They follow the same process as they did the first round with no added weight. Each round, mass, time, distance is recorded on the data table.

Guided Discussion

After completing their data tables, I ask: "What were some of your observations of the car each time you added weight?  I listen for students to share their thoughts. I am looking for them to make the connection to the words force, mass, and acceleration.  

Then I ask: "Why does the car roll down the ramp?" (I am looking for them to identify gravity, as we have been learning about throughout this unit)

As part of our discussion, I reiterate that objects with greater mass will travel less distance than an object of less mass. I explain that objects with larger masses produce larger changes. To get an object to move faster, more force is needed. I continue and explain the car stays at rest until it is placed on a ramp, where it begins to roll as gravity pulls it down. We also discuss how the added weight while on a ramp causes the car to travel faster and farther down the ramp with the help of gravity. I point out that if the car was not on an inclined plane, like the ramp, the added mass weight would actually cause it to move slower.

Elaborate/Evaluate

15 minutes

Data Analysis

After the investigation and guided discussion, I hand out a data analysis assignment to each student. I explain that they are using their data tables to help them answer questions related to activity. Once they finish the questions, they create a line graph with their data and construct an explanation about it. The last piece of the assignment is to connect Newton's 2nd Law to their activity. 

Students work on this assignment for the remainder of class and finish for homework.  I collect it the next day and use as a formative assessment.