Developed by Chantier 7 project team members
Instructional goals: Students will be able to: (1) Understand the concepts of motion transmission and transformation, (2) Explain why motion transmission and motion transformation systems are used, (3) Explain differences between motion transmission and motion transformation systems, and (4) Identify common motion transmission and motion transformation systems
Grade level: Grade 7, 8
Duration: 75-150 minutes
Instructional Materials: Baskets of household items, items for junk sculpture. Please find sample materials in the description of the Activity Option #2 activity section.
The following video link provides an interactive lesson of motion transmission and motion transformation systems: http://cdpsciencetechno.org/cdp/UserFiles/File/previews/mechanisms/
After opening the link, click on the dialogue box (it says prologue at the beginning) and scroll down to 4.1 Motion Transmission and Motion Transformation
Worksheets: Appendix A. Also, please refer to the Eureka Teacher Guide B EN 45 & EN 46
QEP POLs for secondary cycle 1 relevant to the concept of function, components and use of motion transmission systems: Names motion transmission systems in technical objects (friction gears, pulleys and belt, gear assembly, sprocket wheels and chain, wheel and worm gear)
Children’s preconceptions relevant to the concept of motion transmission and motion transformation systems:
1. Students confuse the functional differences between motion transmission and motion transformation systems. For instance, students confuse rotational motion transmission of a gear train with the combined rotational and translational energy transformation of a rack and pinion.
2. Students find it difficult to conceptualize differences between the specific systems.
Description of the Lesson
The goal of this activity is for students to (1) correctly identify five motion transmission systems and four motion transformation systems and (2) understand the differences between motion transmission and motion transformation. This lesson plan includes the following steps:
Step 1: Eliciting Student Thinking/Intuitive Models: In this step, teacher can choose from one of the activities (i.e., Activity Option #1 – Background Knowledge Probes (BKPs) or Activity Option #2 – Let’s categorize the motions!), in order to help students make the topic of motion transmission and motion transformation relevant to their daily life.
Step 2: Collecting and Making Sense of Data: this step follows the previous Activity Option #2 – Let’s categorize the motions!. In this step, teacher follows up with a class discussion and starts with a class discussion on how groups sorted the objects and collect students’ reporting data on the board.
Step 3: Developing Evidence-Based Explanations: Following a class discussion on categorizing motions of objects, teacher engages in this step by introducing a hands-on activity, Junk Sculptures of Two Motion Transmission and Two Motion Transformation Systems, to consolidate students’ understandings of motion transmission and motion transformation systems. Students then participate in a gallery walk where they go around the class and discuss the sculptures made by other groups in the classroom.
Step 4: Evaluation: Teacher can assess students’ learning outcomes by inviting students to write reflective journals on similarities and differences between the nine systems.
Details and procedures of each step in the lesson plan are explained as follow:
Step 1 of the Lesson: Eliciting Student Thinking/Intuitive Models
In this step, teacher can choose from one of the activities (i.e., Activity Option #1 – Background Knowledge Probes (BKPs) or Activity Option #2 – Let’s categorize the motions!), in order to help students make the topic of motion transmission and motion transformation relevant to their daily life.
In order for students to understand the importance of learning motion transmission and transformation, begin the lesson by asking students what they see in their life that involves the motion. For example, teacher can say:
Before we start, I want you to think about if you have seen any technology (or anything) on the way school today that involves ‘motion’, such as, car, trains, elevator, our arms etc.?”
“We are going to start learning about motion transmission and motion transformation.”Can you think of any household objects that use a circular motion to move objects? Do any of you ride an object that uses circular motion? Has anyone seen an object used to dry laundry that uses circular motion? Can you think of examples where round and round motion is changed into up/down motion ? What do you use if you have dry lips? What must happen for lip gloss to move up or down through its container?
Note: At this point the teacher should not introduce the scientific terms, such as rotational motion and translational motion because the intent is to elicit students’ intuitive ideas about the motion of different objects.
- Round and round à rotational motion / circulation motion (e.g., a bicycle, clothsline)
- Up/down motion, or back and forth motion à translational motion ,( e.g., lip gloss)
Ø Recording students’ ideas: Teacher can write down students’ responses on a board or chart paper or teachers can re-voice students’ responses to summarize what the students are saying in different ways.
Ø Orienting students to each other's’ thinking. Teacher can re-voice students’ responses and connect the students’ response to the idea of motion transmission and transformation.
Then, teacher can introduce this lesson by saying: “As you mentioned, there are lots of things in our life that involve motion. However, there are different mechanisms that these motions work. In today’s lesson, we are going to learn about how motions work in the technologies we see around our daily life.” After introducing the topic, teacher can choose one of the following activities (i.e., Activity Option 1: Background Knowledge Probes (BKPs) or Activity option #2: Let’s categorize the motions!) to further explore students’ prior knowledge related to motion transmission and transformation.
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Activity Option #1 – Background Knowledge Probes (BKPs) |
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Part 1: In order to identify to students’ prior knowledge, skills, attitudes, experience and motivation, the teacher can ask the following question:
The teacher can use clickers to obtain students’ responses. If the school does not have clickers, teachers can ask questions of the whole class. Students can raise their hands. If there is no answer from students, teachers can also ask them to write their answers on a piece of paper and put them in a box. The teacher will then write some responses on the board (or a chart paper) for discussion. Part 2: Pressing for explanations: After presenting and discussing students’ answers with them, ask students to talk about their reasoning, explaining their responses either in small groups or in a whole class discussion. Sample guiding questions are: We see that many of you chose option C as an answer. Would anybody want to share why they chose letter C? Summarize why you chose letter C. Teacher introduces the terms “motion transmission and motion transformation.” Then, the teacher can further probe students’ understanding by asking them to think about the difference between motion transmission and motion transformation.
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Activity Option #2 – Let’s categorize the motions! |
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Activity Option #2 follows the introduction and discussion of the concepts, motion transmission and transformation. The goal of this activity, titled Let’s categorize the motions!, is to have students: (1) observe and experience the different motions working of different gadgets and (2) to have students to observe the different direction of motions. The activity has two parts: Part 1: Motion: Transmission or Transformation The purpose of this part of the lesson is to orient students to the key concepts of motion transmission and motion transformation by making the connection between everyday items and the new vocabulary (motion transmission and motion transformation). The video mentioned above in this instructional material could also be useful: http://msdewolflcchs.weebly.com/uploads/2/1/0/6/21063404/motion_transmission_systems_and_motion_transformation_systems2014.pdf Ask students to fill in the following table. There are examples/pictures of each system in the textbook, or on the internet (see video link as well as other internet links). Ask students to think of one more example for each motion system. Students can work in groups. and use their textbooks or other resources to articulate their ideas:
Note: please find the answer key as Appendix A of this lesson plan. Part 2: Gadget Sorting The purpose of Part 2 is to give students a hands-on opportunity to look at the motion transmission and motion transformation systems in everyday objects. Students should have an idea of what each system looks like from Part 1. Pass around baskets of household gadgets that use these systems, and have students determine the type of motion (transmission or transformation) and the specific system (gear train, screw and nut, etc.) used by each gadget. Students work in groups of 3 with the baskets. Many of these objects can be purchased at a dollar store. For example:
While the baskets are in front of the students, have them sort the gadgets into items that are similar. Teacher can ask the following questions and apply the same sort of questions to other concepts:
Notes: While students are working on categorizing the gadgets, teachers can circulate around the classroom to probe them about their observations, explanations/reasoning. The ultimate goal is to guide students to think that motion transmission does not require changes in the direction of the motion (rotational motion stays in rotational motion as the “systems/gadgets” moves) vs. motion transformation – there is a change in the direction in motion – (rotational to translational or vice versa). For example, if a student is observing an egg beater, point out the two gears with teeth. Ask: “ Do the gears move rotationally or rotationally and translationally? Ask similar questions for the remaining gadgets.
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Step 2: Collecting and Making Sense of Data
Once students are finished with sorting tasks described above in the Activity Option #2 – Let’s categorize the motions!, teachers can follow up with a class discussion on HOW groups sorted the objects. The goal of this step is to start the discussion with students’ reporting their data.
The class discussion needs to be channelled to the point that students understand differences between motion transmission and motion transformation. At this point, a Think-pair-share strategy can be used to help students reflect on their ideas and share without feeling alienated and pressured. Then, have all groups sort their objects as motion transmission or motion system systems, and identify the specific system incorporated in the object.
Students can fill in a table such as the one in Appendix C. Based on the group discussions, have each student fill in the below table individually. Also, display the same data table on the board. Discussing as a class will be held after individual students have their forms filled.
The teacher then invites students to share their response within their groups. One option to create a safe space for all students to share their ideas during the whole class discussion, is the teacher can create three colour cards and hand them out to individual students. The colour cards include: Red: Stop! I need help!; Green: Keep going, I understand!: and Yellow: Wait! I am a bit confused! (please see the sample cards in Figure 1). Before the class discussion, the teacher asks the students to use the colour cards given to indicate their comfort level with the topic (either as a group or an individual).
Figure 1. Sample of Colour cards
Next, the teacher invites students to share their responses with the class. Teachers can facilitate discussion using the following practices:
Ø Pressing for evidence: For example, if the student said the gear train is a transmission system, then the teacher can ask: “what do the gears do that led you to think that the gear train is a transmission system?”
Ø Orienting students to each others’ thinking: For example, teachers can ask: “who thinks they understand what (student A) just said and can explain it in their own words? Does anyone want to add to what (Student A) just said? Who agrees with what Student A just said? Why?”
Ø Connecting students’ ideas: For example, teachers can ask: “So, we just said that gear trains are transmission systems because all gears are moving rotationally. How does that connect with Student A’s idea? How does that connect with what we know about other gadgets involving motion transmission?”
Once students share their data and the class has reached a consensus, the teacher may begin to fill in the data table on the board (See Appendix C). During the class discussion, the teacher can ask the students to think about discrepancies, such as “why does group A say _X__ and group B says _Y__?.”
Once collecting students’ data on the board, teachers can move on to a discussion of motion transmission and transformation based on students’ based on the data table in Appendix C. Teachers can say: Most of you have seen patterns. The parts in some gadgets move in the same direction (e.g., gear trains) and some don’t (e.g. rack and pinions). When the parts move in the same direction, it is rotational motion, and this is called motion transmission. When there is a change in the type the motion from rotation (circular or round and round) to translation (up/down), this is called motion transformation.
After explaining the concepts of motion transmission and transformation, teachers can ask all students to hold up their colour cards.
Note: This is to verify students’ understanding of these concepts in a manner that “creates a safe space for learning”. Based on the colour cards, teachers can re-teach and reinforce these concepts or move on to the next activities described below.
Step 3: Developing Evidence-Based Explanations
Activity: Junk Sculptures of Two Motion Transmission and Two Motion Transformation Systems
The goal of this activity is to provide students with an opportunity to prepare a design and build transmission and transformation systems to consolidate their understanding of these systems. During the lesson, the teacher provides the following items for students:
- Corrugated plastic or cardboard or foam board (gears, cam and follower, rack and pinion)
- Elastic bands (belt and pulley, pulleys)
- Assorted Screws and nuts
- Gear templates (photocopies of gears that students can use to make gears or a sprocket using the cardboard) For example: http://www.hometrainingtools.com/media/reference/Gears.pdf
- Rack and pinion templates. For example, see http://www.emachineshop.com/machine-shop/Rack-and-Pinion/page415.html
- Brass paper fasteners
- Wool or string to make a chain for a sprocket
- Paper clips, scissors
- Lids from jars (useful for making belt and pulley, friction gears).
Next, ask students to prepare a design plan BEFORE they begin to create their systems. The design plan should indicate where the force is applied to the object, the main components used to build the object; the motions involved using standard symbols (for more details, please see Eureka textbook A, p 384, or Eureka textbook B, p. 388, or the video link above, as well as the internet URLs provided. Have students make two motion transmission systems and two motion transformation systems using the materials supplied for the class. Students should label their system and summarize the key features and use of the system during a gallery walk (below) or in writing.
In order to help students brainstorm their ideas about the design, the teacher walks around the class listening to their ideas, clarifying conceptual issues relating to the two types of motion systems and directing them productively. Students might need help with cutting the corrugated plastic/cardboard/foam board and attaching various parts.
Upon completion, organize a gallery walk where students go around the class and discuss the sculptures made by other groups in the classroom. Each group presents their work. As the gallery walk progresses, the teacher asks questions about each group’s sculptures. The purpose of the questions is to elicit students’ thinking and to provide an opportunity for students to express their ideas to the rest of the class. Probing questions could include:
- How are the two transmission systems the same or different?
- How are the two transformation systems the same or different??
- What were some of the difficulties you experienced while building the systems?
- Were some systems easier to build than others? Explain some of the problems you encountered.
- What is the key difference between motion transmission and motion transformation systems?
Note: Worksheets are available for use (Eureka textbook B), or Appendix A.
Step 4: Evaluation
Post-assessment could involve a journal type reflection of similarities and differences between the nine systems using a table, or students could complete the worksheet provided in Appendix A. Assessment of the design plan is also recommended. The teacher can also administer the multiple choice assessment question that was included at the beginning of the lesson (Activity Option #1).
This lesson plan is inspired by the following resources:
Tran, K.-T., & Escrivá, I. (2008). Eureka!: Science and technology, secondary cycle one. Montréal: Graficor Chenelière Éducation.