Lesson Plan Template: Learning Cycle (5E Model)
Learning Objectives: What will students know and be able to do as a result of this lesson?
- Students will contrast elastic and inelastic collisions.
- Students will explain how the total momentum before a collision relates to the total momentum after a collision for elastic and inelastic collisions.
- Students will calculate momentum for various situations.
- Students will apply the Law of Conservation of momentum to both elastic and inelastic collisions.
- Students will define momentum, its symbol, and its units.
Prior Knowledge: What prior knowledge should students have for this lesson?
- Students should have a basic understanding of the difference between vector and scalar quantities.
- Students should understand how to use proper units when solving an equation in Physics.
- Students should be familiar with Google Apps and manipulating electronic simulations in general.
Guiding Questions: What are the guiding questions for this lesson?
- What is the difference between elastic and inelastic collisions?
- A bullet is fired at a block of wood. The bullet becomes lodged in the block of wood, which moves backward after the collision. Is this an example of an elastic or an inelastic collision? How can you tell?
- What do Physicists mean when they say that a quantity is "conserved"?
- In what situations would it be possible for a bumblebee and a tiger to have the same momentum?
- How can the Law of Conservation of Momentum be used to explain the motion of two billiard balls after they collide?
Engage: What object, event, or questions will the teacher use to trigger the students' curiosity and engage them in the concepts?
There are a number of ways to complete this demonstration, depending on the materials available. The general idea is to take an object and throw it horizontally to land on an object with wheels, so they both move forward together. For instance, if you have available a skateboard, you could take a book and toss it onto the skateboard on your front demonstration table or desk, so that it is visible to the class. You could also (carefully) quickly walk and hop onto a moving chair, so that you roll forward in the chair.
After the demonstration, lead a Think-Pair-Share* activity with the class to answer the following questions:
- How did the textbook cause the skateboard to move?
- When the textbook and the skateboard rolled off, did they have greater speed, less speed, or the same speed as the textbook before it hit the skateboard?
Once you pose the questions, you may need to show the class the demo a second time (and possibly a third and fourth time as they analyze the motion visually).
If you cannot perform the demonstration live, you may wish to use the following clip from UNSW Australia's PhysClips, authored by Joe Wolfe: (requires Adobe Flash). Link to page containing other momentum clips: PhysClips Momentum Clips.
*Think-Pair-Share: Students think about the questions individually, then discuss their ideas with a partner, then there is a general discussion for students to contribute and share their thoughts with the class.
After the discussion, students complete the following five question Diagnostic Assessment:
Momentum-Diagnostic Assessment with Answer Key
Evaluate the statements below as either true or false.
- Momentum tells us how much energy an object has.
- It is possible for a small car to have the same momentum as a large truck if the car moves very fast.
- Momentum is the product of an object's mass and its speed in a straight line.
- If a 70 kg human is walking at 2 m/s, her momentum is 35 kg/m/s.
- If an object is not moving, it still has nonzero momentum because it still has mass.
If possible, it is recommended that the students complete this assignment electronically (for instance, through the CPS system, if available) so that the teacher might have immediate feedback as to the students' prior knowledge.
Explore: What will the students do to explore the concepts and skills being developed through the lesson?
Two Part Investigation: Part 1 - Hands-on, Conceptual; Part II - Virtual, Quantitative
Part I: Introduction to Momentum for cars of different mass
This investigation has students collide small cars on tracks. The cars can have mass added to them. As written, the procedure uses the CPO Energy Car kit (as seen ), but the lab could easily be completed with any small cars on tracks that have variable mass. It is important that the cars roll fluidly and easily. You should assign students into groups of three. Once in their groups, students assign themselves roles based on the guidelines in the lab.
If tracks are not available, students can complete the activity on a smooth table top or on the floor. The most important thing is that the cars are able to roll smoothly and fluidly. If desks are small or the floors are rough (for instance carpet or small tiles), a track could be improvised by using smooth boards, for instance from a bookshelf.
The teacher has two main options for students to complete the lab: the lab can be printed out and distributed, or the teacher may use a Google Form. The link for both options are below. If the teacher chooses to use the Google Form, it is critical that the teacher makes a copy of the Google Spreadsheet below and sends the students to the link for that form. If you send the students to the form linked to below, their answers will become public on the Spreadsheet linked below.
Collision Investigation Part I: Google Spreadsheet (make a copy of this to use it for your class)
Collision Investigation Part I: Google Form (to review - do not send your students to this link!)
Collision Investigation Part I: Worksheet
Part II: Elastic vs. Inelastic Collisions and the Law of Conservation of Momentum
Collision Investigation: Part II Worksheet
Note: Before completing Part II of the investigation, students should complete Part I of the Explain section. Students need to understand how to calculate momentum before proceeding.
Part II leads students to discover the qualitative difference between elastic and inelastic collisions and then leads students to discover the Law of Conservation of Momentum. The simulations in this part of the investigation require Adobe Flash in order to run.
It is recommended that you post this lab on your class's website for students to view while they are performing the lab. They can then record their answers by hand as they complete the simulation on the computer. You could also have your students complete their answers and submit their labs electronically. To do this, send them to the document below and have them make a copy. They can then add their own responses to the questions and share their completed lab with you using Google Apps.
During both Part I and Part II of the investigation, the teacher should circulate through the class to monitor for understanding and support students as they complete the activity.
Explain: What will the students and teacher do so students have opportunities to clarify their ideas, reach a conclusion or generalization, and communicate what they know to others?
Part I: Introduction to Momentum
Momentum: Explain - Part I Worksheet
Momentum: Explain - Part I Answer Key
This part of the Explain section has students read a website and answer questions about momentum. Students' answers to these questions then become their notes for the unit.
If you do not have a class set of computers so that students can read the website, your classroom textbook could easily be substituted for the website. Find the section in your text that gives an introduction to momentum (definition, equation, description as a vector) and adjust the assignment accordingly.
After students complete Explain Part I you have two options. Option 1: Go over the answers to the worksheet as a class. You could lead a class discussion in which students provide and defend their answers. Option 2: You could provide a copy of the answer key to students when they finish so that they may review and correct their work individually.
Explain Part II is abbreviated. Students should understand the basics of the Law of Conservation of Momentum from Explore Part II. The following assignment can be completed either as it is written (which has students read a website) or you could have students read the appropriate section from your class's textbook. You could also simply have a class discussion to cover this concept, in order to break up the self-paced assignments.
Momentum: Explain Part II
Momentum: Explain Part II - Answer Key
At two points in this assignment, students are directed to check their answers with the teacher to make sure they are on the right track. This allows the teacher direct opportunities for formative assessment of student progress and understanding.
The teacher could also show the following video, either as an introduction before the students complete Explain Part II, or as a review after it is completed: Conservation of Momentum in Space
Elaborate: What will the students do to apply their conceptual understanding and skills to solve a problem, make a decision, perform a task, or make sense of new knowledge?
Students will complete a worksheet independently to practice the concepts and skills learned in the lesson.
Momentum: Practice Worksheet
Momentum: Practice Worksheet - Solutions
When students complete this worksheet, the teacher may either collect the students' responses and grade them, to give students formal feedback, or the teacher may give the students copies of the solutions so that they may check their own work.
It is recommended that students are allowed to check their own work on this worksheet, particularly the calculations portion. The provided solutions include all of the steps to solve the problems, so that if students make a mistake they can see where it occurred and understand why to prevent repeating the mistake in the future.
Another option would be to give the students a partial set of solutions (for instance, only the odd problems). The student could then self-check these problems and then make corrections to the remaining problems. The teacher would then formally grade the remaining problems.
For the summative assessment, students will take a traditional multiple-choice, True/False, and fill-in-the-blank assessment, which includes a calculation section.
The equations for momentum, elastic collisions, and inelastic collisions are provided on the assessment for the student to reference. If you prefer not to provide your students with equations, they can easily be removed by making a copy of the assessment in Google Apps and then removing the equations.
Momentum: Summative Assessment
Momentum: Summative Assessment - Answer Key
Students can take this assessment either by hand or by inputting it into an automatic grading system, such as the CPS system. If the students hand write their answers, then the teacher may assign partial credit for the Calculation portion of the exam if a student applies the correct equations, but does not arrive at the correct answer.
There are a number of opportunities in this lesson for the teacher to gather both formal and informal formative assessment data.
- Engage: There is a diagnostic assessment to gather data on prior student knowledge concerning momentum. This could be done informally (students could put thumbs up if they believe an answer is true, thumbs down if they believe an answer to be false) to gather general data or formally (written or digitally input answers) to gather specific student data.
- Explore: During Explore I and II the teacher should circulate to check for student progress and understanding. The teacher may wish to ask selections from the Guiding Questions during this time in order to verbally assess student progress. The students are also instructed to check their answers with their teachers at various points during the investigation. This will allow the teacher to monitor student progress directly.
- Explain: Again, during this section the teacher should circulate throughout the class to monitor and support student progress. By asking questions of students and answering student questions during this time, the teacher will gather formative assessment data. There are a few points in the assignment in which the student is instructed to check their answers with their teacher. This will allow the teacher to monitor student progress directly.
- Elaborate: The teacher may formally grade the students' responses to the practice worksheet. The teacher should also be circulating among the class to monitor and support student progress as they practice the calculations.
Feedback to Students
Students will receive informal feedback from their teachers throughout the lesson. At several points in both the Explore and Explain sections, students are instructed to check their progress directly with their teachers to ensure that they are on the correct path.
Furthermore, the teacher may choose to formally grade students' work in the Explore, Explain, and Elaborate sections. There is also an option for teachers to give students the opportunity to self-check their work in the Explain and Elaborate sections.
In all of these cases, the teacher will provide direct or indirect feedback for students to check their understanding and correct (if necessary) before progressing. If students self-check during the Elaborate section, they will have the opportunity to clearly understand their mistakes so that in future problems they will be able to improve their performance.