Investigating Newton's Third Law-Action = Reaction
Lesson 6 of 8
Objective: SWBAT explain Newton's Third Law of Motion- Action = Reaction.
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.
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.
In this lesson, Newton's Third Law of Motion- Action=Reaction, I begin by showing a video of a rocket launching to spark their curiosity. They make predictions as to how it supports Newton's third law of motion. From there, they design a canister rocket and conduct three trials. They use their evidence to analyze the cause and effect of each launch and how Newton's third law of motion explains it. The lesson ends with students completing a reflection of the entire investigation. I use this a formative assessment.
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.
Students are engaged in the following scientific and engineering practices:
3.) Planning and Carrying Out An Investigation- Students conduct an investigation by creating a canister rocket produce evidence of Newton's Third Law of Motion and use their understanding to explain how an action results in a reaction.
The Newton's Third 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 actions create reactions. They use their observations to understand the effects of Newton's Third Law of Motion.
Disciplinary Core Ideas within this lesson include:
PS2.A - Forces and Motion
PS2.B- Types of Interactions
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.
I begin by directing students attention to the whiteboard, where I project a video of a rock launching into space. I show this video because they are launching a canister rocket later today to observe Newton's third law of motion.
Next, I ask them what they noticed? I listen to their observations. Then I tell them to think back to our lesson on Newton's Law's of Motion and to recall his third law. (They have a reference sheet from their research that they can refer to if necessary.)
I guide them by asking them several questions:
- How did the rocket move? (It pushed off the ground)
- Which direction did it in move in? (Upward motion)
- Were there any other things moving? Explain. (the gases/fuels moved in the opposite direction, causing the rocket to push off the ground and up into the air)
- Did the gases/fuels move in the same direction as the rocket? (no it went in the opposite direction.)
I reiterate the terms action and reaction from Newton's law and ask them what those terms mean. I explain that they are going to investigate these terms by creating their own rocket to launch.
Preparing to Investigate
I hold up a film canister and pose the question, "Do you think we can get this to launch in the air like the rocket we saw in the video?" I am not looking for an answer, rather encouraging them to think about the question. I continue, telling them they are working as lab rats today to conduct multiple trials to launch the canister (rocket). The lab rats':
- Director- leads the group, making sure all members participate
- Materials manager- responsible for supplies: retrieving them, members use them correctly etc.
- Technician- tracks the launch time and flight time of the canister rocket
- Reporter- shares the data their group collected with the whole class
I hand out a Canister Rocket task card with data table and have them set up their interactive notebooks. Then each lab rats' material manager retrieves the supply tray and I go over the materials they are using(film canister, safety eye glasses, a large bottle of water). I let them know that there are three different sizes of alka-seltzer tablets.
Next, I review the task card directions, explaining that we are launchingour rockets outside. I tell them they will get the alka seltzer tablet when we are outside and groups show that they ready to launch. I make sure to point out a few key points about putting the canister together and launching the canisters by demonstrating the following practices:
- When opening and closing the lid, it is important to hear a snapping sound, so water and air do not leak out.
- Safety glasses must be worn at all times.
- Measuring and filling 1/2 of the canister with water. (I show them on the canister about where that would be)
- Placing an alkaseltzer in quickly and snapping the lid closed. (I open it right after so the canister does not launch)
- Placing it on the launch pad, counting how many seconds it take to launch and how many seconds the rocket stays airborne
- Recording the times for launching and in flight on their data table.
*We had three days of rain when I taught this lesson and ended up doing the launches inside. Groups went one at a time for safety reasons. They still had a great learning experience.
Before heading outside, we go over rules, expectations, and responsibilities for our behavior and task. I do this prior to going outside for management purposes and to set them up for success.
Once we are outside, I point to our launch pad area. (I give each group their own area/space to work in so they can be productive and on task.) I remind them of their roles and responsibilities and they begin.
While they are launching their rockets, I am moving between groups observing, listening, and asking them questions like to make sure they are grasping the concept:
- what are you noticing?
- why do you think that happens?
When groups have completed their rocket launches, we head inside to further analyze our data and discuss how the activity connects to Newton's Third Law of Motion.
Canister Rockets Connection Newton's Third Law of Motion
I start by posing the question: "what action made the rocket canister “explode” and allow the rocket to react and launch?"
I tell students to think about Newton's Third Law- For every action there is an equal and opposite reaction and discuss with your group how this activity shows how this law work. I have a few students share their ideas to the class. I tell their classmates to listen carefully as I may call on them to repeat an idea state or if they agree or disagree with what was being said. This encourages them to be active listeners.(I will embed student ideas here once taught)
I am looking for students to make the connection that as the alka seltzer dissolved, it created pressure inside of the canister (from the*carbon dioxide released), pushing against the sides of the container and forcing the top to come off to release the gases. This is the action. As a result, the canister was pushed into the air. This is the reaction. I add on and explain that the more pressure that builds up inside of the canister before the lid pops, the faster the gases are released, which cause the canister to reach greater height.
*(Students may not know the the fizzy gas is actually carbon dioxide. I give a brief explanation to this by relating it to the bubbles and fizzes of soda, as soda is something they are all familiar with)
I point out that real rockets work in the same way. I remind them of the video we started off with at the start of the lesson and explain how the rocket uses fuel to force it (action) to move up and away (reaction) from the launch pad surface. The rocket goes in the opposite direction of the gas. The quicker the gas leaves the rocket, the faster it gets launched. This shows us how every action has an equal and opposite reaction.
Reflecting On Our Investigation
I hand out a "Rocket Reflection" assignment that students begin in class and continue for homework. This assignment ask students a series of assignment related to the canister rocket activity and its relation to Newton's third law of motion.
I collect this assignment the next day and use as a formative assessment.