LESSON PLAN: MOMENTUM

Candidate: Brian Turkett

Date:Thursday, December 10, 2009

Cooperating Teacher:Michael Occhino

Grade Level: 9

Subject Area:Physical Science

Duration:80 hours

Title of Unit:Momentum

Lesson Title:Impulse-MomentumTheory

Goals and Objectives

Goals: 1) Students will understand that an impulse causes a change in momentum.

2) Students will understand that momentum conservation follows from Newton's third law of motion.

3) Students will understand that an impulse is a force that is exerted over an interval of time.

Objectives: 1) Students should be able to explain how an impulse creates a change in momentum through jumping off of a chair and observing/discussing the behaviors that we find occur in our knees when we hit the floor and discussing automobile crashes as to how they relate to a constant force over time.

2) Students should be able to support with evidence the claim that momentum is conserved through deriving the equation from Newton’s third law of motion, observing and explaining Newton’s Cradle, and through use of the air puck collisions.

3) Students should be able to design an investigation that studies the momentum of a system and produces data and graphs that represent the impulses and conservation of momentum within that system.

National and New York State Standards:

New York State Standard: Physics

5.1p The impulse imparted to an object causes a change in its momentum.

5.1r Momentum is conserved in a closed system. xii. verify conservation of momentum

Assessment:

Formative:

The formative assessments for this lesson include class discussions with student answers to guiding questions to the topics of momentum and impulse. These answers will be recorded on the board by a scribe as a conceptual knowledge timeline that we can build upon and improve over the course of the lesson. Further formative assessments will be made through questioning of conceptual connections using demonstration enhancements such as Newton’s cradle and jumping off the chairs.

Summative:

The summative assessment is a process driven authentic assessment that focuses on students designing, implementing, and analyzing their own investigation in regards to momentum and the conservation of momentum. This lab design and implementation should fall over this lesson and the next day’s lesson. Students should be able to produce graphs of momentum vs. time and force vs. time using Excel and should be able to explain the purpose of these graphs in explaining conservation of momentum and impulse.

Community Knowledge and Experience:

Students can bring in their knowledge and experience of automobile design and functions, particularly in collision situations. The knowledge of an air bag and what its purpose is, why the frame is set up to collect the impact, what happens when a car hits a wall. Also, knowledge of why when we jump down we bend our knees upon impact. Their knowledge of how important our spine is and how the impact that the contact would create up the spine into the brain can be harmful, even life threatening. The same concepts can be applied to rockets. Student knowledge of how rockets expel gas at one end and move in an opposite direction. This can tie Newton’s third law of motion directly into the concept of momentum and impulse.

Procedures/Format:

0:00 – 0:10

Ask students to take out their lab notebooks. What is momentum? Students will provide definition and related answers in a classroom discussion. These answers will be recorded on a board (ask for a scribe?). Answers could be “something to move you forward”, “movement”. Where have you heard this word before? Use examples to further discussion, ie. Cars, collisions, crashes, rivers, rockets, etc.

0:11 – 0:20

Demo: Newton’s Cradle (ask for volunteer?) – Why do the balls fly up on the opposite side? Explain how this makes sense using our definitions of momentum.

0:21 – 0:30

Let’s think about automobiles. Why do they build them with air bags? Why do they have a cage frame? Collisions precautions. Ask for volunteer. Say “Run into that wall at fall sprint for me.” Student will respond no. Say ok, “let me go to the City Mattress and pull some of the mattresses of the wall and put them up there. Now would you do it?” Answer may be yes, if no “well what is different about this system now that we’ve changed it?” What have we done in terms of an object’s momentum? Answer should be increased the time of impact – Impulse! Impulse = Force * Time.

0:31 – 0:40

Demo: Find a partner. Stand on chair. Now jump off. What did you notice when your partner hit the ground? What did you notice about the ways your knees bent? Try it again. Why do we always bend our knees?

0:41 – 0:75

Connect the previous lessons of this week on friction and air resistance to the air table, which makes frictionless surface. “So, we have this table that pushes air up out of it. This gets rid of the surface so normal force disappears. Air resistance is neglected because the pucks are not in free fall.” So, lets take a look and now add in collisions: “How can we use this tool to look at collisions? What kind of questions can we ask to test collisions? What will we ultimately want to learn about from these collisions?” Present a list of materials that students can use, i.e. Video, photographs, meter sticks, probes, etc. Make a list of independent and dependent variables to test. Independent variables may be changing masses of objects in collisions, changing distances of objects, changing forces of objects. Students will write up a procedure that investigates a question related to collisions of petri dishes on the air table, such as “how do different size/mass petri dishes impact each other when they collide?” Procedure should be detailed so that we can follow the steps of what the students will be doing to carry out the lab, including materials they will use, and why and how they will use them.

Before students proceed to carry out the lab they must get their lab procedure and design approved by Mr. Occhino, or myself. Tie string down the center of air tables to make eight groups. Students will design an experiment that aims to verify the conservation of momentum. The investigation will be made around air tables with air pucks. Data should be collected that will allow students to make two graphs, 1. momentum vs. time, 2. Force vs. time. This data should include mass, velocity of the object (calculated by distance moved over time), acceleration of object (calculated by distance and time – s=.5at^2), and force (f=ma). Students will need meter sticks, stopwatches, an air table, air pucks, scale or balance.

0:75 – 0:80

Questions to ask after the lab: What does it mean to be conserved? What is the significance of before collision data and after collision data?

If students have not made it to a point where they can answer these questions then ask: What variables do you think are important in collisions? How might mass and velocity be related to collisions?

Extra Activity:

Video - Waterslide (Bad Physics) (http://www.youtube.com/watch?v=OV9mo_TuG9g)

What is bad about this video? Why is this not a real phenomena?

Safety:

Students will need to use safety precautions in the laboratory setting. This will take place with the air tables and air pucks. Students will be informed to pay special attention to and to take care of the materials used in this lab by mentioning the purpose of collisions, and having the awareness that the pucks may be flying off of the air table. As preparation students should plan to catch these pucks before they fly off the table.

Resources:

Air tables

Air pucks

Meter sticks

Stopwatches

Lab Notebooks

Newton’s Cradle

White Board

Powerpoint

Chairs

Human beings

Applications, Connections and Extensions:

Students will find relations to Forces and Newton’s Laws of Motion in the calculations of impulse and momentum. They will also gain experience of these connections through demonstration and activity. Parallels can be drawn to rocket motion and car collisions. Students can relate rockets to the third law with opposite forces, and extend this into momentum and impulses. With car collisions students can apply the knowledge of a car hitting a wall and what happens to the car, what happens to a passenger, and relate the system in terms of initial and final momentums. Sports can also be tied in, such as baseball bats hitting a ball applying a force over time, and the same idea for other sports. The affect of rebounding, for instance if you threw a ball against a wall, can also be applied to the concepts of impulse and momentum.


Inclusive Instruction:
The inclusion in this lesson is found in the activities that students are asked or allowed to do. There will be volunteers to scribe or assist with demonstrations. Specific attention should be made to providing women the opportunity to participate in these demonstrations. The momentum lab activity will be constructed by the students, letting them build on their strengths and design them into the procedures and implementation of the investigation.

Reflection:

My pluses for today are as follows: 1. Letting students take on active roles and participating in the class discussion. These included the duty of having a scribe take notes of student answers to such things as "what is momentum" and questions around lab design such as "what questions can we ask using this air table" and "what are possible independent variables". Students also participated by demonstrating Newton's cradle and the jumping/knee bending demonstration. 2. My use of student's prior knowledge through questioning was particularly strong, i.e. "Remember Newton's laws, how can they tie into momentum?" 3. Letting the students develop their own inquiry lab, and the presentation of this material in a scaffolded way. I showed the students what materials we had available and questioned them in how they might build a question to test what we have discussed about momentum and how we might do this with the materials. Also, I questioned students to create a list of independent variables to test.

My arrows: 1. I introduced a lot of content that would fit better after students’ have practiced the concepts in their lab. I need to work on scaffolding this knowledge better by limiting the amount of detail in my information until after student activity has a chance to break conceptions and build evidence of phenomenon. 2. I often restate a question that is perfectly fine and do not wait for students to answer. I should prepare some well-written questions beforehand and write them down on slides or remember them to present. 3. I also often restate a student's answer, which confirms their thinking but places the teacher's approval of the answer on it. I should let the students take more ownership of the answer by saying, "wow, that was a well thought out answer" or "did you hear that because that was a great explanation". Also including other students by asking, "what do you think of that" or "how are you thinking about this".

I feel my plan could use some consideration in the introduction of material. I have a hard time understanding how in depth of an introduction students will need before they investigate the concepts through inquiry themselves. I believe some of the things I introduced, such as the derivation of momentum and impulse could have been left for after the students have some hands on knowledge of the scientific phenomena. I can improve this I think by asking more open-ended and thought provoking questions before an inquiry activity. I feel the students get frustrated with a lot of these questions, so if I could tie in demonstrations and visuals that enhance the learning I think the students would benefit a great deal through making connections in this manner. I would also like to continue using open inquiry activities. We have not talked about this much in class and I think it can be a very valuable tool to have the ability to implement. As such, I want to try to get as much practice with it as I can before I am through with the program. As far as assessment of student knowledge, I will need to figure out a way to include formative assessments that capture all students’ conceptions and understandings. Worksheets that they hand in, such as 3, 2, 1’s, or ticket out the doors may be perfect for this assessment.