Developed by Chantier 7 project team members
Instructional goals: Students will be able to: (1) Understand the mechanical function of linking, (2) Explain why links and guiding controls are used, (3) Explain characteristics of different links, and (4) Identify four characteristics of a variety of links used in everyday objects, (5) Identify types of guiding controls in everyday objects.
Grade level: Grade 7, 8
Duration: 75-150 minutes
Instructional Materials: Baskets of household items or items used at school or in a science lab or items is student pencil case or clothes. Please find sample materials in the description of the Activity Option #1 activity section. The following video link provides an interactive lesson about links: 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 3.1 Links and 3.2 Guidance.
Worksheets: Appendix A. Also, teachers in Quebec can refer to the Eureka Teacher Guide B U2 p. 53 & EN 40
QEP POLs for secondary cycle 1 relevant to the concept of links:
1. Describes the role of links and guiding controls in a technical object
2. Identifies a guiding control in a technical object, as well as the related links (e.g. a pizza wheel is guided by a pivot, which links it to the handle)
Children’s preconceptions relevant to the concept of motion transmission and motion transformation systems
1. Students tend to confuse the vocabulary used in links. For instance, students confuse some direct/indirect links. A light bulb screws into the socket, but there is no third component providing a link BUT if a coat hook is held to the wall with a screw, then the link is indirect since the screw in this case is a third component.
2. Students may find it difficult to conceptualize differences between links and guiding controls because guiding controls function both to guide movement, and they are also links. An example is a screw, or the lid on a glue stick: they are both links and guiding controls.
3. Some students have difficulty distinguishing the difference between rotational and helical guiding.
Description of the Lesson
The goal of this activity is for students to (1) correctly use the terminology associated with links, (2) to correctly identify different links when examining an object, and (3) understand and identify the three types of guiding controls. 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 links!), in order to help students make the topic of links 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 links! In this step, the teacher starts a class discussion on how groups labelled the links they looked at in their objects, and collect students’ reporting data on the board.
Step 3: Developing Evidence-Based Explanations: Following a class discussion on categorizing links (included below), the teacher engages in this step by introducing an activity using links in sports equipment, Links and Guiding Controls in Sports Equipment, to consolidate students’ understandings of the mechanical function of links and guiding controls. Students then participate in a gallery walk where they go around the class and discuss the sports equipment analysis made by other groups in the classroom.
Step 4: Evaluation: Teacher can assess students’ learning outcomes by inviting students to write reflective journals on links found in common everyday activities.
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 links!), 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 about links and guiding controls, begin the lesson by asking students what they see in their life that involves links. For example, teacher can say:
Before we start, I want you to think about if you have seen any technology (or anything) in the classroom today that involves objects held together, such as objects in your pencil case, or in your notebooks, or on your clothes etc. How can you describe the ways the parts of the object are held together?”
“We are going to start learning about what holds parts of an object together, and what controls the motion of moving parts..” Can you think of any household objects that moves in circles? What about objects that move up and down? Or back and forth? Let’s think about objects where parts are held together. What do you use if you have dry lips? What holds the pieces together? How do the parts move with each other?
Note: At this point the teacher should not introduce the scientific terms, such as rotational, translational, or helical guiding, nor the vocabulary about different linking characteristics because the intent is to elicit students’ intuitive ideas about links and guiding controls found in different objects.
Ø Recording students’ ideas: The 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. The teacher can re-voice students’ responses and connect the students’ response to the idea of motion transmission and transformation.
Then, the teacher can introduce this lesson by saying: “As you mentioned, there are lots of things in our life that involve holding objects together, and about controlling motion. However, there are different mechanisms that these motions work. In today’s lesson, we are going to learn about how things are held together, and how motions are guided in the technologies we see in our daily life.” After introducing the topic, the teacher can choose one or both of the following activities (i.e., Activity Option 1: Background Knowledge Probes (BKPs) or Activity option #2: Let’s categorize the links!) to further explore students’ prior knowledge related to links and guiding controls.
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Activity Option #1 – Background Knowledge Probes (BKPs) Guiding Controls |
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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:
Note: The teacher may re-voice their explanations and write their responses on the board. The teacher then introduces the terms “links” and “guiding controls”. Then, the teacher can further probe students’ understanding by asking them to think about the characteristics of different links, and the difference between translational, rotational and helical motion in objects being guided. |
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Activity Option #2 – Let’s categorize the links! |
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Activity Option #2 follows the introduction and discussion of the concepts, links. The goal of this activity, titled Let’s categorize the links! is to have students: (1) use the vocabulary associated with links as they observe linked (2) to have students to observe the different types of guiding controls. The activity has two parts: Part 1: Links and Guiding Controls The purpose of this part of the lesson is to orient students to the key vocabulary used when discussing links by making the connection between everyday items and the new vocabulary (direct or indirect; removable or non-removable; rigid or elastic; complete or partial). The video mentioned above in this instructional material could also be useful: http://www.emsb.qc.ca/laurenhill/science/LinkinginTechnical%20Objects.pdf Ask students search in their pencil cases, look at their clothes, or the teacher can provide a variety of household items OR lab equipment. Students should find a minimum of 5 different links. Next they summarize the characteristics of their links in the following table. There are also examples/pictures of links in the textbook, or on the internet (see video link as well as other internet links). Students also evaluate the object to determine if there is a guiding control. Students can work in groups, and use their textbooks or other resources to articulate their ideas:
Part 2: Evaluation of Links and Guiding Control in Sports Equipment The purpose of Part 2 is to give students an opportunity to apply the terminology of link characteristics and guiding controls found in sports equipment. Students should have an idea of the characters of links, and the types of guiding controls from Part 1. The day before this activity is to be embarked upon, students should be asked to bring in pictures of sports equipment. OR, students could access pictures in the school library OR they can use their personal devices to find pictures. They should have a minimum of five links to evaluate. Possible examples include: hockey skates, helmets and sticks, football cleats and helmets, gymnastics apparatus, bicycles and bike helmets, track and field equipment, or possibly ballet slippers and the bar in a ballet studio, etc. Each group of students should look at the pictures of their equipment. They should then create a table to organize their data, or they could use the same table as provided in Part 1. Students should then complete the worksheet in Appendix A.
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Step 2: Collecting and Making Sense of Data
Once students are finished with analyzing their everyday links, Activity Option #2 – Let’s categorize the links and guiding controls! teachers can follow up with a class discussion on WHY each groups used the classifications they chose. 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 direct or indirect; removable or non-removable; rigid or elastic; complete or partial, as well as the differences between the three types of guiding controls: translational, rotational and helical. 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 each group justify their classifications. It would be interesting to have students who chose helmets or shoes to compare the links as each type of helmet has links that are uniquely different.
Students can fill in a table such as the one in Appendix B. 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 that a shoe lace is indirect, removable, complete and rigid, then the teacher can ask: “how is the shoe lace functioning that led you to think that the shoe lace is indirect, removable, complete and flexible?
Ø Orienting students to each other’s 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 that the shoe lace is indirect, removable, complete and flexible because the lace connects the two parts of the shoe, it can be removed with damaging the lace, is does not allow the shoe halves to move, and it is not flexible. How does that connect with Student A’s idea? How does that connect with what we know about other footgear, for example shoes with Velcro?”
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 B). 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 links and guiding control based on students’ data table in Appendix B. Teachers can say: Most of you have seen patterns. The parts in some sports equipment are linked in similar ways, and some are different.
After explaining the concepts of links and guiding controls, 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.
Upon completion of Part 2, organize a gallery walk where students go around the class and discuss the pictures with the link characteristics and guiding control developed 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 links on the pictures the same or different?
- How are the guiding controls the same or different??
- What were some of the difficulties you experienced when characterising the links and the guiding controls?
- Were some links easier to characterize than others? Explain some of the problems you encountered.
- What is the key difference between links and guiding control 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 ten links, and the guiding controls students used in the two activities using a table, or students could complete the worksheet provided in Appendix B. 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:
Tran, K.-T., & Escrivá, I. (2008). Eureka!: Science and technology, secondary cycle one. Montréal: Graficor Chenelière Éducation.
Special thanks to Ms. Heather McPherson for her insights and contributions to this lesson.