TE Activity: An Arm and A Leg
Contributed by: K-12 Outreach Office, Worcester Polytechnic Institute
Summary |
Engineering Connection |
| Bioengineering technologies explore the production of mechanical devices, products, biological substances, and organisms to improve health and/or contribute improvement to our daily lives. |
Contents
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| Grade Level: 7 (6-8) | Group Size: Not defined |
| Time Required: 3 hours |
Activity Dependency  :None |
Expendable Cost Per Group
:
US$ 5 |
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| Keywords: Artificial limb, System, Water, Air, Gas, Bioengineering, Prototype, Sub-system, Blueprint, Liquid, Assistive technology | |
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Related Curriculum
:
| subject areas | Life Science Science and Technology |
Pre-Req Knowledge (Return to Contents)
Students should have prior experience with, or introduction in the following concepts: hydraulics, joints, muscles, tendons, ligaments, bones, states of matter.
Learning Objectives (Return to Contents)
After this activity, students should be able to:
- Understand that movements of bones are dependent upon the interaction of pairs of muscles
- Identify the major bones and muscles of the arm and leg
- Realize that a force (push or pull) is needed for movement
- Realize that movement is a complex process involving more than one body system
- List all body systems involved in movement
- Understand that the location of muscle attachment is important to the movement of the bone
- List and describe the working of different joints
Materials List (Return to Contents)
For each group:
- 14 - 10 mL oral syringes
- 7 - 30 cm length pieces of ¼" aquarium tubing
- 20 Popsicle sticks
- 5 Rubber bands
- 1 meter of Duct tape
Introduction/Motivation (Return to Contents)
NASA is currently working on setting up a workstation on the moon. You are part of a team that has just landed there. One of your team members has an artificial arm and leg and has lost functionality of his limbs. It is up to your team to design and build one of the replacements. The only materials at your disposal are: popsicle sticks, string, duct tape, water, and aquarium tubing and these materials must be shipped from the main shuttle located above the moon to the station where your team is located.
Vocabulary/Definitions (Return to Contents)
| Articulate: | To connect with a joint |
| Bone: | Rigid connective tissue that makes up the skeleton of vertebrates |
| Compression: | The process of pressing items together |
| Contract: | To draw or squeeze together so as to make or become smaller or shorter and broader |
| Force: | To break open or through |
| Gas: | A phase of matter in which the molecules are widely separated, move around freely, and move at high speeds |
| Ligament: | A tough band of tissue that holds bones together or keeps an organ in place in the body |
| Liquid: | Liquid is a phase of matter which is free to conform to a shape of a vessel but has a fixed volume and has a greater density than a gas |
| Muscle: | A body tissue consisting of long cells that can contract and produce motion |
| Newtons: | The unit of force that is of such size that under its influence a body whose mass is one kilogram would experience an acceleration of one meter per second per second |
| Relax: | To make or become loose or less tense |
| Solid: | A solid is a phase of matter characterized by resistance to deformation and to changes of volume |
| System: | A group of objects or units combined to form a whole and to move or work together |
| Tendon: | A tough cord or band of dense white connective tissue that links a muscle to some other part |
Procedure (Return to Contents)
Basic Procedure:
- The group must design a robotic arm or leg that simulates the body movement of that part.
- The design should include a sketch with all parts labeled. For example: Popsicle sticks will represent bones and label the bone (humerus). Please refer to the design sketch rubric.
- Now decide how many syringes, popsicle sticks, rubber bands and length of duct tape the team will need. Fill out the materials request form and submit form to obtain materials.
- The next step is to build a prototype of the device.
- Now test and evaluate the design based on the rubric provided.
- Each group is to share their design and demonstrate how it works in relation to movements and parts of the body. Remember to use appropriate terminology.
How to Create a Hydraulic System:
- Put together two syringe sub-systems. A sub-system will be defined as a piece of tubing with a syringe attached at each end. See Figure 1.
Figure 1 - Fill one sub-system with water. Do this by removing both plungers from the syringes.
- Now place the open end of the syringe side A under a water faucet while holding syringe B at a lower elevation. Fill the sub-system with water until it overflows. Turn water off.
- Holding both syringe A & B at an equal elevation, place plunger A into syringe A and push plunger SLOWLY all the way down. Water will enter syringe B filling it completely.
- Finally, place plunger B into syringe B. Make sure that the plunger is in contact with water and not air. If necessary, top off syringe B with water.
- This is a hydraulic sub-system because it contains a liquid. The other sub-system is filled with air (gas) and it is called a pneumatic sub-system.
Attachments (Return to Contents)
- Hydraulic Sketch Rubric (doc)
- Hydraulic Sketch Rubric (pdf)
- Hydraulic Test and Evaluation Sheet (doc)
- Hydraulic Test and Evaluation Sheet (pdf)
- Hydraulic Robots 101 (doc)
- Hydraulic Robots 101 (pdf)
- Student Worksheet: Device Procedure (doc)
- Student Worksheet: Device Procedure (pdf)
- Student Worksheet: Fluid Capacity (doc)
- Student Worksheet: Fluid Capacity (pdf)
Safety Issues (Return to Contents)
There is always a chance of a rubber band flying out of control or a popsicle stick making and unscheduled detour across the room.
Troubleshooting Tips (Return to Contents)
- Students may have difficulty filling up the tubing and syringes with water. Remember there should not be any air in the line.
- Students arm or leg prototype may buckle, if this is the case students should look at the placement of the rubber band and change it
Assessment (Return to Contents)
Pre-activity assessment
Have students draw a diagram of an arm and/or leg. Have students draw where the muscles, ligaments, tendons are located and explain how they work.
Activity Embedded assessment
Students are to keep a journal of their daily process.
Post-activity assessment
Students ability to present and explain how the arm/leg works using the appropriate terminology as it relates to the rubric.
Activity Extensions (Return to Contents)
Math Activity Idea
NASA has accepted your design and wants to have several devices on hand to avoid any further delays in the future.
- Based on the material used by your team create a list of materials, amounts used, and prices for a single device.
- Now compute the cost for 5, 10, 25, and 100 devices. Your material supplier will reduce your cost by 15% if you make 100 devices. How much can you save with this 15% discount?
Materials for each group:
- 15 - 10 mL oral syringes
- 8 - 30 cm length pieces of ¼" aquarium tubing
- 6 - Popsicle sticks
- 5 - Rubber bands
- 1 meter of Duct tape
Math Activity Attachments
Copyright
© 2005 by Worcester Polytechnic Instituteincluding copyrighted works of other educational institutions; all rights reserved
Supporting Program (Return to Contents)
K-12 Outreach Office, Worcester Polytechnic InstituteLast Modified: September 26, 2008