Students will: Explain how the muscles and bones of the human body function together as levers. Justify categorization of lever types.

Transcription

1 PHYSICAL THERAPY Essential Question: How Is the Body Like a M achine? Learning Targets: Students will: Explain how the muscles and bones of the human body function together as levers. Justify categorization of lever types. Lesson Overview Biomechanics is the application of the principles of mechanics (physics) to the living body. The body s skeletomuscular system is comprised of levers that give it mechanical advantage when working with the force of gravity to produce movement. Physical therapists understand these principles and use them to rehabilitate injuries so that people can experience normal range of motion in their joints and movement that is not compromised. In this lesson, YPs will explore the action of levers and how the body is made up of many levers. 1

2 Lesson Agenda Opening (10 min) Emergency Scenario: Rehabilitation (10 min) Work Time Biomechanics: An Exploration in Levers (20 min) Lever Vocabulary Basics (5 min) Card Sort Protocol (20 min) Closure (5 min) Careers in Biomechanics Materials: Young Allied Health Professional student packet Modeling the arm as a lever activity (one per pair of students) <How Is Your Arm a Lever?> procedure Table Bucket with a strong handle Sand or other material to put in the bucket Categories of types of levers (one per group) Lever example cards (one set per group) Lever vocabulary post-its (one set per group) Card sort answer key (for teacher reference) Card sort student directions (to project) FACILITATION NOTES The Narrative Arc. The more each <Emergency Scenario> can be presented as if telling a story, the more engaged the audience will be. Work to avoid a stale reading and lean towards bringing the information to life as in a conversation or a reveal of the next chapter. Think of creative ways to make the story your own. Partners. Students are very active in this lesson. Be sure they change colleagues and work with different students throughout. Background Information on Levers. Need a review of levers? See this 12 minute video at: 2

3 Optional Videos: The Mighty Mathematics of the Lever. Breaks down the parts of a lever. Animated but advanced, illustrates see-saw as a lever with multiple examples: Building Lever Models. Invite students to build the three types of levers and see simple machines in action: Levers/dp/B003DKJEC4/ref=sr_1_2?s=toys-and-games&ie=UTF8&qid= &sr=1-2&keywords=levers. IN ADVANCE Have a device available to project instructions. Review the Card Sort protocol. Review the Biomechanics Challenge Questions (for teacher reference). Vocabulary Content biomechanics, fulcrum, effort, load, external, internal Tier II categorize, range, effort Opening (5 min) Even after injuries, like broken bones, have been fixed and are healing, patients often need a physical therapist to help them experience less pain and to regain some of the freedom they should have in their movement. Emergency Scenario: Rehabilitation 1. Ask: Have any of you or anyone you know needed physical therapy for any reason? 2. Invite volunteers to share their experiences. 3. Ask: Does anything from science come to your mind when you hear the term biomechanics? 4. Invite volunteers to provide answers. Listen for: bio like biology. Mechanic. Simple machines, levers, force, etc. If the young professionals do not know, assure them In order to connect the activities to the career of PT, show this short video as part of the opening. Otherwise, the activities may seem disjointed. 3

4 that in this lesson they will be learning about how the body uses simple machines, like levers, to move. 5. Share the <Emergency Scenario: Rehabilitation> in a conversational, engaging way. 6. Show this video to build background knowledge and connect the lesson s activities to the role of a PT. (3:33). Work Time Biomechanics: An Exploration in Levers (20 min) Our bodies use a lot of levers to accomplish the work of movement. Physical therapists also use their knowledge of biomechanics, or the ways our bodies are like machines, to assess and treat people s injuries so that they can move more normally and experience less pain after they heal. Understanding how levers work and the types of levers that make up our bodies is very important information for the physical therapist. How is your arm a lever? 1. Did you know parts of our body function as simple machines? Project video that shows how to balance using one s arm as a lever: (1:25). Note the terms used in the left corner. 2. Model the activity. o Fill a bucket halfway with sand or a bag with books (determine the number based on size and weight of the books available in the classroom). o Place your arm flat on the table with your hand and approximately four inches below your wrist extending over the edge of the table, palm facing upwards. o Invite a YP to hang the prepared bucket/bag across the palm of your hand. o Keeping your elbow on the table, lift the bucket up. o Ask: On a scale of 1-5, how much effort did it take to lift the buckets/bag? (1= no effort and 5= a lot of effort.) State your impression aloud. o Have the YPs record their data in the table. o Model filling the bucket with sand/adding books to bag. o Check for Understanding: I would repeat this experiment with the new weight, keeping my elbow and arm in the same placement. I am only changing one variable. What variable am I changing? 4

5 2. Model extending the effort arm by using a yardstick, but do not repeat the experiment. 3. Invite the YP to read the <How Is Your Arm a Lever?> procedure in their packet. o As they read, distribute materials to partners. Lever Vocabulary Basics (5 min) 1. Distribute the <Lever Vocabulary>. o Tell the young professionals that a seesaw is a type of lever. You will use it as an example to use the vocabulary in context, and everyone should label the image on their page as they follow along. o Distribute one sticky note (labeled fulcrum, effort, load, and resistant point) to each group. 3. Project the seesaw image from the <Lever Vocabulary> handout. 4. Invite groups to discuss where they would place their label. Allow time to discuss, then use equity sticks to call on representatives from each group to bring their label and place it on the projection. 5. After all groups have added their labels, ask if anyone has any suggested changes to the label placements. o The lever and the base is the fulcrum. o The effort would be the child lifted into the air. o The load is the child on the ground. o Resistance force, in this case, is gravity. o The mechanical advantage is what allows a child to lift the weight of another child even a child who is much bigger, or an adult! 2. Check for Understanding: Think back to your arm in the lifting activity. What was the fulcrum? The load? The effort? Now that you have a better understanding of how levers work, we re going to work on classifying tools that we use all the time into the categories of the 3 types of levers. We ll then use this information to figure out the type of lever the arm is. With this understanding, we can then assess and rehabilitate the broken arm injury sustained by the young skateboard accident patient. 5

6 Card Sort Protocol (20 min) 1. Invite the young professionals to form groups of 3 or Explain that they will be doing some problem solving together through the Card Sort protocol that will deepen their learning around levers. In their small groups, they will study the <Categories of Types of Levers> and match the lever example card to the category. o Note that some tools, like scissors, use two of the same type of lever to accomplish their work; each blade is a lever in the scissor example. 3. Project the <Card Sort Student Directions> and read them aloud. 4. Ask: Who can explain how to do the Card Sort? o Remind students that the cards for the card sort take time to prepare, so they should keep the cards together in the same group and not fold or write on them. The card sort offers an opportunity to think critically about connecting lever types to real world objects. Focus on reasoning and thinking, not on the correct answer. Ask: Why did you classify the object that way? 5. Model spreading the cards out so everyone in the group can see them and participate fully. o o o o Think aloud to model how to make the claims: o Say: The seesaw is a Class 1 lever based on the evidence provided by the placement of the fulcrum it is in the middle, and the effort and load are placed at either end of the arm. Feel free to use the lesson PowerPoint to help you think aloud. Continue the think aloud for placing nail clippers in the Class 2 lever category. Nail clippers are actually a class 2 and class 3 lever at the same time. Explain that you are helping them think through the most difficult example for class 2 levers. The top arm of the clippers is class 2. The fulcrum of the nail clippers is where the two arms come together to do the cutting. The load is near the middle, close to the cutting end. The effort is the opposite end that you push down on to make the cutter work. Salad tongs are Class 3 levers. Just like nail clippers, the fulcrum is the end where the two arms join. The effort, however, is the force you apply to pick up your salad. So the load is on the end doing the picking up. Ask: What did you notice about how I sorted the cards? Call on volunteers to answer the question. Listen for: You thought about the parts of a lever to try to decide what category it belonged in. 6

7 6. Emphasize the importance of communication in the allied health professions. Project the <Card Sort Sentence Starters> and explain that these will help them frame their conversations. 7. Distribute the <Categories of Types of Levers> and the <Lever Examples Cards> to small groups. o o Circulate and provide support as needed. When the groups complete the task, ask: What were some of the reasons for sorting the cards the way you did? 8. Invite groups to talk about these reasons for 30 seconds. o Cold call using equity sticks. Answers will vary. 9. Invite YPs to complete the <Biomechanics Challenge Question>: What class of lever is at work when you raise a glass of water from a table to your mouth? Explain the sources of the fulcrum, resistance (or load), and effort. o Invite the young professionals to turn and talk to a colleague and think through the movements involved in the task provided in the question. o Use equity sticks after a few moments of discussion to solicit responses. Sentence starters often feel awkward to first implement. However, with regular use, they support independence in students higher quality discussions. Model the starters in your own discussions and acknowledge when the YPs use them in conversation. Rephrasing students comments using the starters is another strategy. Closure (5 min) Careers in Biomechanics Today, we learned that Physical Therapists rely on the principles of biomechanics to help their patients recover from injuries. However, many other careers require the use and application of biomechanics. Can you think of other careers that rely on biomechanics? 1. Provide think time for the YPs. 2. Encourage paired thinking and sharing of ideas. 3. Use equity sticks to solicit responses. 4. Ask: What careers did you come up with? 5. Listen for: Athletes, Athletics Coaches, Athletic Trainers, Community Recreation Instructor, Orthopedic Surgeon, Biomechanics Researcher. 7

8 The point of this brief closure is to get students to transfer their new knowledge of biomechanics to the real world. Where else would this knowledge be useful outside of a hospital? 8

9 Name: Date: PHYSICAL THERAPY: How Is the Body Like a Machine? Today s Learning Objectives: I can: Explain how the muscles and bones of the human body function together as levers. Justify categorization of lever types. Biomechanics is the application of the principles of mechanics (physics) to the living body. The body s skeletomuscular system is comprised of levers that give it mechanical advantage when working with the force of gravity to produce movement. Physical therapists understand these principles and use them to rehabilitate injuries so that people can experience normal range of motion in their joints and movement that is not compromised. In this lesson, I will explore the action of levers and how the body is made up of many levers. Today s Activities: Emergency Scenario: Rehabilitation Biomechanics: An Exploration in Levers Card Sort Protocol Careers in Biomechanics 9

10 Emergency Scenario: Rehabilitation After any trauma to the body, rehabilitation of the injured areas is usually required as an important part of treatment. As a physical therapist in the hospital, you see a variety of injuries and problems that arise with the skeletal-muscular systems as a result of disease. Your latest patient, an adolescent boy with a brain contusion and a broken arm, has been assigned to your caseload. In analyzing his case, you will focus on physical therapy exercises to regain movement and strength in his broken forearm. Since you were in middle school, science was your favorite subject, especially physical science. In high school, you discovered that physics can be applied to the human body in an area of study called biomechanics. What you really love about your career is that you can apply what you know about physics to the human body in order to help people feel better. 10

11 How Is Your Arm a Lever? Procedure (adapted from e-fair/article/human-machine/) 1. For this activity, you can use either a bucket of sand or a bag filled with books. 2. Fill the bucket halfway with sand or the bag with books provided by your teacher. 3. Place your arm flat on the table. Your hand and about four inches below your wrist should extend over the table s edge. The inside of your elbow should be facing upward. 4. Have your friend hang the bucket/bag across the palm of your hand. 5. Keeping your elbow on the table, lift the bucket up. 6. Repeat, this time with the bucket full of sand/with double the books. 7. On a scale of 1-5, how much effort did it take to lift the buckets? (1= no effort and 5= a lot of effort.) Record your answer in the data table. 8. Remove sand/books until the bucket is again halfway filled. 9. Put the handle of the bucket around a yardstick. 10. Set your arm on the table as before, but hold the yardstick with the bucket hanging off it. The bucket/bag should be 2-3 feet farther from the edge of the table. 11. Lift the bucket again. 12. On a scale of 1-5, how much effort did it take to lift the bucket/bag this time? (1= no effort and 5= a lot of effort.) Record your answer in the data table. 13. Slide the bucket/bag to different places on the long stick and note the different amounts of effort. Arm Only: Bucket ½ Full Arm Only: Bucket Full Stick Extension: Bucket ½ Full Stick Extension: Bucket Full Participant 1 Participant 2 11

12 14. Use your data table to help you answer the following questions: How does the effort to lift the bucket on the long stick compare to the effort of moving it when it was in your hand? Does it feel like the bucket contains more or less sand than the first trial? Explain your reasoning. 12

13 Lever Vocabulary Vocabulary Word Prediction of Meaning Definition (and picture) Lever Fulcrum Effort Load Resistance Force Mechanical Advantage 13

14 Biomechanics Challenge Question Bones and Muscles as Levers (adapted from the Haspi curriculum) The study of biomechanics applies concepts of physics to the movement of the body. While the biomechanical movement of the human body is complex, there are also some simple machines at work. The movement of the body results from the interaction between bones, muscles, and joints. Many of these interactions form a simple biological machine known as a lever. Within the human body, bones are considered the lever arm; the axis of a joint is the fulcrum; resistance is created by the weight of the body part or object being moved or pushed upon; and muscles are considered the effort since they create the actual motion. What class of lever is at work when you raise a glass of water from a table to your mouth? Diagram and label the sources of the fulcrum, resistance (or load), and effort. Class of Lever: Diagram (with labels): What class of lever is at work when you lift a barbell over your head? Explain the sources of the fulcrum, resistance (or load), and effort. 14

15 Facilitation Documents: 15

16 Card Sort Student Directions 1. Spread the cards out on the desk so that everyone in your group can see them. 2. Group members should examine all cards and discuss and determine how to sort them before moving any cards. 3. Group members should work as a team to sort cards together, taking turns moving the cards. Card Sort Sentence Starters What does everyone think about? I m wondering if we want to. I agree/disagree with the idea because. So we re saying. It sounds like we agree that. Do we all agree that? Is there anything here we have a question about? 16

17 Classification of Types of Levers Production: Cut the following classifications of types of levers apart. Then, cut the <Lever Example Cards> apart. Class 1 A class 1 lever has the fulcrum placed between the effort and load. The movement of the load is in the opposite direction of the movement of the effort. This is the most typical lever configuration. 17

18 Class 2 A class 2 lever has the load between the effort and the fulcrum. In this type of lever, the movement of the load is in the same direction as that of the effort. Note that the length of the effort arm goes all the way to the fulcrum and is always greater than the length of the load arm. Class 3 A class 3 lever has the effort between the load and the fulcrum. Both the effort and load are in the same direction. Note that the length of the load arm goes all the way to the fulcrum and is always greater than the length of the effort arm. 18

19 Lever Example Cards HAMMER S CLAW PLIERS 19

20 CATAPULT 20

21 BOTTLE OPENER STAPLER 21

22 WHEELBARROW 22

23 NAIL CLIPPERS CROWBAR FISHING ROD 23

24 TWEEZERS MOUSETRAP 24

25 BROOM SALAD TONGS 25

26 WALNUT CRACKER 26

27 Card Sort Answer Key (for teacher reference) Class 1 Levers Seesaw Hammer s Claw Pliers Catapult Bottle Opener Class 2 Levers Stapler Wheelbarrow Nail Clippers Crowbar Walnut Cracker Class 3 Levers Fishing Rod Tweezers Salad Tongs Mousetrap Broom 27

28 Lever Vocabulary Vocabulary Word Prediction of Meaning Definition (and picture) Lever A solid beam or rod that rests or pivots on a fulcrum. Fulcrum The point on which a lever rests, is supported, or on which it pivots. Effort The applied force a person puts into the lever. Load The weight or mass that is supported by the lever. Resistance Force The force that must be overcome to do the work. Mechanical Advantage The number of times a machine multiplies the effort (applied force). 28

29 Biomechanics Challenge Question (for teacher reference) Bones and Muscles as Levers (adapted from the Haspi curriculum) The study of biomechanics applies concepts of physics to the movement of the body. While the biomechanical movement of the human body is complex, there are also some simple machines at work. The movement of the body results from the interaction between bones, muscles, and joints. Many of these interactions form a simple biological machine known as a lever. Within the human body, bones are considered the lever arm; the axis of a joint is the fulcrum; resistance is created by the weight of the body part or object being moved or pushed upon; and muscles are considered the effort since they create the actual motion. What class of lever is at work when you raise a glass of water from a table to your mouth? Diagram and label the sources of the fulcrum, resistance (or load), and effort. Raising a glass of water from a table to your mouth is done with a class 1 lever. The forearm acts as the lever arm, the elbow joint is the fulcrum, the resistance is the forearm and glass of water, and the effort is created by the bicep muscle. What class of lever is at work when you lift a barbell over your head? Explain the sources of the fulcrum, resistance (or load), and effort. Lifting a barbell over your head is done with a class 3 lever. The humerus bone, radius, and ulna (the arm bones) are the fulcrum. The resistance is the arm and the weight. The effort is created by the trapezius and deltoid muscles (chest and back muscles). 29