This document is a companion piece to video titled Engineering for Mobility and is intended as a resource for educators.
Background and Planning Information
About the Video
This video features Rory Cooper, a biomechanical engineer at the University of Pittsburgh and participant in the 1998 Summer Paralympics games in Seoul. In his Human Engineering Research Laboratories, Cooper and his graduate students are doing research on how wheelchairs are designed and built, depending on the sport played, and sometimes on the position played by the athlete. The video also discusses the concept of the center of gravity of various types of wheelchair designs.
| 0:00 | 0:12 |
Series Opening |
| 0:13 | 0:26 |
Summary of the 2012 Paralympics events |
| 0:27 | 0:57 |
Introducing Rory Cooper |
| 0:58 | 1:12 |
Research done in Cooper’s lab |
| 1:13 | 1:22 |
Designing different wheelchairs for different sports |
| 1:23 | 2:17 |
Wheelchairs designed for rugby |
| 2:18 | 2:53 |
Center of gravity in wheelchairs |
| 2:54 | 3:47 |
Wheelchairs designed for basketball |
| 3:48 | 4:36 |
Wheelchairs designed for racing |
| 4:37 | 5:06 |
Summary |
| 5:07 | 5:16 |
Closing Credits |
Language Support
To aid those with limited English proficiency or others who need help focusing on the video, make transcript of the video available. Click the Transcript tab on the side of the video window, then copy and paste into a document for student reference.
Connect to Science
Framework for K–12 Science Education
- PS2.A: Forces and Motion
- PS2.B: Stability and Instability in Physical Systems
Related Science Concepts
- Center of gravity
- Balance
- Mass
- Density
- Fulcrum
- Speed
- Mobility
- Biomechanics
(page 1)
Connect to Engineering
Framework for K–12 Science Education
- ETS1.A: Defining and Delimiting Engineering Problems
- ETS1.C: Optimizing the Design Solution
- ETS2.B: Influence of Engineering, Technology, and Science on Society and the Natural World
Engineering in Action
The problem addressed in Science of the Summer Olympics (SOTSO): Engineering for Mobility is how to design a stable wheelchair given the needs of the person using the wheelchair. While Dr. Cooper’s lab focuses on sporting equipment, the concepts can be applied to wheelchairs for everyday use. In designing and building any wheelchair, special attention is paid to the chair’s center of gravity—the point at which both the chair and the person’s mass are equally distributed in all directions. In sporting and other specialized uses, a lower center of gravity coupled with other design modifications results in less tipping of the chair. For everyday use, a higher center of gravity might result in a higher possibility of tipping, but it also makes the chair easier to get in and out of, and better positions the user for general and household tasks in environments not adapted for specific accommodations. The materials and design of a wheelchair are also important—size of wheels, number of wheels, need for bumpers, overall weight, and so on. These will vary depending on whether the user moves the chair or whether someone else is pushing the chair. This research involves several engineering knowledge-generating activities, including transfer from science, design practice, and direct trial.
Engineers hone their ability to design a system, component, or process to meet desired needs within realistic constraints, such as economic, environmental, social, political, ethical, health and safety, manufacturability, and sustainability.
Take Action with Students
Help students brainstorm to form a list of some of the constraints within which engineers have to work to design the wheelchairs used in Paralympic events. Possible responses include economics, the environment in which the chairs will be used, the health and safety of the users, and the manufacturability and sustainability of the chairs, among others. Have students make recommendations for the parameters of the constraints they list. Use the list to initiate a discussion about using durable yet lightweight materials in the chairs. Extend the discussion to include engineering design problems associated with other types of equipment used in sports, including golf clubs, tennis racquets, javelins, poles used in vaulting, running shoes, safety helmets and other protective equipment, and bicycles, among others.
Inquiry Outline for Teachers
Encourage inquiry using a strategy modeled on the research-based science writing heuristic. Student work will vary in complexity and depth depending on grade level, prior knowledge, and creativity. Use the prompts liberally to encourage thought and discussion. Student Copy Masters begin on page 6.
Explore Understanding
While most students are probably not conscious of it, they change their center of gravity in many of their daily motions and activities. Slinging a backpack over one shoulder, for example, causes them to shift their masses to the opposite sides of their bodies to compensate, thereby changing their centers of gravity from their midlines to their sides. Likewise, carrying the backpacks on their backs shifts their centers of gravity backward, causing them to lean forward to compensate and keep their center of gravity in the center. If possible, have one or two volunteers use their backpacks to demonstrate these changes. As students closely observe the volunteers, use these or similar prompts to spark a discussion about the center of gravity of an object or a system.
(page 2)
- Without a backpack, _____ stood....
- When_____ slung the backpack over his/her shoulder, he/she shifted his/her mass to the....
- When _____ wore the backpack on his/her back, his/her center of gravity moved....
- I think that the center of gravity of an object or a system is the point where....
Show the video SOTSO: Engineering for Mobility.
Continue the discussion of center of gravity and balance, using prompts such as the following:
- When I watched the video, I thought about....
- The expert in the video claimed that _____ because....
- To stay upright, the wheelchairs used by rugby players have....
- The center of gravity in wheelchairs used by basketball guards vary from those used by forwards and centers in that....
- Wheelchairs used by racers are different from those used by rugby players in that....
- Wheelchairs used by racers are different from those used by basketball players in that....
Ask Beginning Questions
Stimulate small-group discussion with the prompt: This video makes me think about these questions.... Then have groups list questions they have about the center of gravity of an object or system of objects, and what factors might affect it. Ask groups to choose one question and phrase it in such a way as to be researchable and/or testable. The following are some examples.
- How might the mass, the height, or a change in shape of an object affect its center of gravity?
- What factors influence the center of gravity of a system of objects?
- How might distribution of mass affect the center of gravity of a system?
Design Investigations
Choose one of these two options based on your students’ knowledge, creativity, and ability level.
Open Choice Approach (Copy Master pages 6-7)
Small groups might join together to agree on one question for which they will explore the answer, or each small group might explore something different. Students should brainstorm to form a plan they would have to follow in order to answer the question. Work with students to develop safe procedures that control variables and enable them to gather valid data. Encourage students with prompts such as the following:
- The variable we will test is....
- The variables we will control are....
- The steps we will follow are....
- To conduct the investigation safely, we will....
(page 3)
Focused Approach (Copy Master pages 7–9)
The following exemplifies how students could investigate effects of redistributing mass on the center of gravity of a simple system.
- Allow time for students to examine the materials you have available to construct simple systems, such as an index card with paperclip attachments or a hollow toy boat with a unit-cube cargo (or any other “standard” mass, such as pennies or marbles). Examining the materials often aids students in refining their questions, or prompts new ones that should be recorded for future investigation. Ask students questions such as the following to help them envision their investigation.
- Where do you think the center of gravity in the card/boat might be?
- How can you locate the center of gravity of the card or boat?
- Will making a system with the card and paperclips affect the card’s center of gravity?
- Will adding cargo to the boat affect the system’s center of gravity?
- In terms of the center of gravity, what might happen if you moved the paperclips around the card or the unit cubes around the bottom of the boat?
- Students might use a pencil with an unused flat eraser to locate the center of gravity of a large index card or an empty boat and to mark that point. Guide them to understand that the center of gravity is at the point where the card/boat balances on the eraser.
- Once students have discovered how to determine the center of gravity of an object, give them free rein in determining how they will explore the effects of adding mass and redistributing it on the card or boat on the card’s or boat’s center of gravity. Use the following prompts to guide students in their thinking.
- The center of gravity of the system is....
- When the “load” of the system is placed symmetrically, the center of gravity....
- When the “load” of the system is placed asymmetrically, the center of gravity....
- Ensure that students brainstorm to form a list of variables involved in this experiment, and determine which can be controlled and which cannot. As needed, help them focus on their proposed procedures by using prompts such as the following:
- The variable we will test is....
- The variables we will control are....
- The materials we will use are....
- We will mark each center of gravity by....
- To conduct the investigation safely, we will....
- Students should use metric rulers to identify each center of gravity in their systems, using the original center of gravity or some other point in the system as a reference. As students carry out their investigations, ensure that they record their observations. As needed, suggest ways they might organize their data using tables or graphs.
- Students might continue their investigations by exploring how using paperclips or unit cubes with the same mass but different densities (plastic-covered versus bare metal clips, or hollow unit cubes versus solid ones) might affect the center of gravity.
Make a Claim Backed by Evidence
Students should analyze their data and then make one or more claims based on the evidence their data shows. Encourage students with this prompt: As evidenced by... we claim... because....
(page 4)
An example claim might be:
As evidenced by the tilting of the card when the paperclips were not equally distributed, we claimthat the center of gravity changes when the mass of an object is redistributed because the location of the center of gravity moved away from the center of the card and toward the end where the paperclips were grouped.
Compare Findings
Encourage students to compare their ideas with others, such as classmates who investigated a similar question or system or with those that investigated a different question or system, material they found on the Internet, an expert they chose to interview, or their textbook. Remind students to credit their original sources in their comparisons. Elicit comparisons from students with prompts such as:
- My ideas are similar to (or different from) those of the experts in that....
- My ideas are similar to (or different from) those of my classmates in that....
- My ideas are similar to (or different from) those that I found on the Internet in that....
Students might make comparisons like the following:
My ideas are similar to those discussed in the video. I found that changing the distribution of mass on an index card or in a toy boat changes the stability of the system. This is similar to what happens in the video when an athlete changes his or her position in a wheelchair and causes the chair to lean or even tip over.
Reflect on Learning
Students should reflect on their understanding, thinking about how their ideas have changed or what they know now that they didn’t before. Encourage reflection, using prompts such as the following:
- The claim made by the expert in the video is....
- I support or refute the expert’s claim because in my investigation....
- When thinking about the expert’s claims, I am confused as to why....
- Another investigation I would like to explore is....
Inquiry Assessment
See the rubric included in the student Copy Masters on page 10.
Incorporate Video into Your Lesson Plan
Integrate Video in Instruction
Bellringer:
Play and replay the video with the sound muted as students are getting settled. Have students answer a question such as: The video makes me think about.... or The wheelchairs you see in the video vary in that.... Allow volunteers to share responses and record them as springboards for your discussion on center of gravity or levers.
Compare and Contrast:
To support a discussion on aerodynamics, have students watch the video, focusing on the segment about wheelchairs designed for racing at 3:48–4:36. Tell students the video focuses on designs used for rugby, basketball, and racing. Instruct students to jot down notes about wheelchair design for a given sport as they watch. Have students use their notes to compare the features of wheelchairs for rugby and basketball to the ideal racing wheelchair, and how that design enables the athlete to go faster.
(page 5)
Using the 5E Approach?
If you use a 5E approach to lesson plans, consider incorporating video in these Es:
Explain: Use the Design Investigations section of the Inquiry Outline to support your lessons on measurements, mass and density, and center of gravity.
Elaborate: Use the video to encourage students to learn more about some of the many factors that affect a person’s center of gravity, including age, gender, body proportions, posture, and the addition of mass that is not equally distributed, such as carrying a shoulder bag or a bucket of water in one hand, just to name a few.
Connect to ... Language Arts
Suggest students find out more about the Paralympics, including how the name was derived. (Although originally a term that combined paraplegic with Olympic, the term has become mainstream as being derived from the Greek word para, that means “alongside,” or “parallel” as in parallel to the Olympics.) Students might research specific athletes or specific sports other than those highlighted in the video. Students could use their research to write on a variety of themes, such as: the engineering and technology that supports Paralympians; third-person perspectives on a “day in the life of...” during competition; a news report on the outcome of an event; or journal or blog entries on some aspect of the Paralympics or athletes themselves. Encourage students to illustrate their writing with photographs from the competitions. Good places for students to start their research are the official London 2012 website and the official website of the Paralympic Movement.
- http://www.london2012.com/paralympics/
- http://www.paralympic.org/
Use Video in Assessment
Project the video segment diagramming the center of gravity in wheelchairs and how it changes (2:18–2:53) with the sound muted. Have students write a short paragraph that explains the science behind the diagrammatic sequence. You might also provide students with screen grabs of the video at 2:19 and at 2:44 and the following instructions: Define the term center of gravity, accurately mark its position on each chair with a pencil eraser-sized dot, and explain which Paralympics sport discussed in the video each chair is likely to be used for.
COPY MASTER: Open Choice Inquiry Guide for Students
Science of the Summer Olympics: Engineering for Mobility
Use this guide to investigate a question about Paralympians, how movement might be improved by wheelchair design, or factors that affect the center of gravity of an object or a system. Write your lab report in your science notebook.
Ask Beginning Questions
The video makes me think about these questions....
(page 6)
Design Investigations
Choose one question. How can you answer it? Brainstorm with your teammates. Write a procedure that controls variables and makes accurate measurements. Add safety precautions as needed.
- The materials I will use are....
- The variable I will test is....
- The variables I will control are....
- The steps I will follow are....
- To conduct the investigation safely, I will....
Record Data and Observations
Record your observations. Organize your data in tables or graphs as appropriate.
Make a Claim Backed by Evidence
Analyze your data and then make one or more claims based on the evidence your data show. Make sure that the claim goes beyond summarizing the relationship between the variables.
|
My Evidence |
My Claim |
My Reason |
|
|
|
|
Compare Findings
Review the video and then discuss your results with classmates who investigated the same or a similar question. Or do research on the Internet or talk with an expert. How do your findings compare? Be sure to give credit to others when you use their findings in your comparisons.
- My ideas are similar to (or different from) those of the experts in that....
- My ideas are similar to (or different from) those of my classmates in that....
- My ideas are similar to (or different from) those that I found on the Internet in that....
Reflect on Learning
Think about what you found out. How does it fit with what you already knew? How does it change what you thought you knew?
- The claim made by the expert in the video is....
- I support or refute the expert’s claim because in my investigation....
- When thinking about the expert’s claims, I am confused as to why....
- Another investigation I would like to explore is....
COPY MASTER: Focused Inquiry Guide for Students
Science of the Summer Olympics: Engineering for Mobility
Use this guide to investigate a question about how the distribution of mass in a simple system affects the system’s center of gravity. Write your lab report in your science notebook.
Ask Beginning Questions
How does the distribution of mass within a system affect the center of gravity of the system?
(page 7)
Design Investigations
Brainstorm with your teammates about how to answer the question. Write a procedure that controls variables and allows you to gather valid data. Add safety precautions as needed. Use these prompts to help you design your investigation.
- The system I will use is _____.
- To accurately determine the system’s center of gravity, I must....
- The reference point I will use to compare my measurements is....
- The variable I will test is....
- The steps I will follow to test my variable include...
- The variables I will control are....
- To conduct the investigation safely, I need to....
Record Data and Observations
Organize your observations and data in a table. The table below is an example using a simple system made up of a large index card and four large paper clips.
How Mass Distribution Affects the Center of Gravity of a System
|
Drawing of the System |
Center of Gravity Relative to a Reference Point in the System |
|
|
|
|
|
|
|
|
|
Make a Claim Backed by Evidence
Analyze your data and then make one or more claims based on the evidence shown by your data. Make sure that the claim goes beyond summarizing the relationship between the variables.
|
My Evidence |
My Claim |
My Reason |
|
|
|
|
(page 8)
Compare Findings
Review the video and then discuss your results with classmates who did the investigation using the same or a similar system or with those who did the investigation using a different system. Or do research on the Internet or talk with an expert. How do your findings compare? Be sure to give credit to others when you use their findings in your comparisons.
- My ideas are similar to (or different from) those of the experts in that....
- My ideas are similar to (or different from) those of my classmates in that....
- My ideas are similar to (or different from) those that I found on the Internet in that....
Reflect on Learning
Think about what you found out. How does it fit with what you already knew? How does it change what you thought you knew?
- The claim made by the expert in the video is....
- I support (or refute) the expert’s claim because in my investigation....
- When thinking about the expert’s claims, I am confused as to why....
- Another investigation I would like to explore is....
COPY MASTER: Assessment Rubric for Inquiry Investigations
|
Criteria |
1 point |
2 points |
3 points |
|
Initial question |
Question had a yes/no answer, was off topic, or otherwise was not researchable or testable. |
Question was researchable or testable but too broad or not answerable by the chosen investigation. |
Question clearly stated, researchable or testable, and showed direct relationship to investigation. |
|
Investigation design |
The design of the investigation did not support a response to the initial question. |
While the design supported the initial question, the procedure used to collect data (e.g., number of trials, control of variables) was not sufficient. |
Variables were clearly identified and controlled as needed with steps and trials that resulted in data that could be used to answer the question. |
|
Variables |
Either the dependent or independent variable was not identified. |
While the dependent and independent variables were identified, no controls were present. |
Variables identified and controlled in a way that results in data that can be analyzed and compared. |
|
Safety procedures |
Basic laboratory safety procedures were followed, but practices specific to the activity were not identified. |
Some, but not all, of the safety equipment was used and only some safe practices needed for this investigation were followed. |
Appropriate safety equipment used and safe practices adhered to. |
|
Observations and Data |
Observations were not made or recorded, and data are unreasonable in nature, not recorded, or do not reflect what actually took place during the investigation. |
Observations were made, but were not very detailed, or data appear invalid or were not recorded appropriately. |
Detailed observations were made and properly recorded and data are plausible and recorded appropriately. |
|
Claim |
No claim was made or the claim had no relationship to the evidence used to support it. |
Claim was marginally related to evidence from investigation. |
Claim was backed by investigative or research evidence. |
|
Findings comparison |
Comparison of findings was limited to a description of the initial question. |
Comparison of findings was not supported by the data collected. |
Comparison of findings included both methodology and data collected by at least one other entity. |
|
Reflection |
Student reflections were limited to a description of the procedure used. |
Student reflections were not related to the initial question. |
Student reflections described at least one impact on thinking. |
