1. Introduction to the Engineering Design Process
Brenda Capobianco
Chell Nyquist
Todd Kelley

2. Engineers
Engineers are responsible for designing many different things in the human-made world.
What might this include?
Engineers are also responsible for designing the less obvious products.
How about chairs?

3. Think about a baby’s high chair vs. a chair in a doctor’s office.
What factors must engineers consider as they design chairs?
Where will the chair be located? (kitchen/doctor's office)
How often will the chair be used? (3 x day/all day)
Will people be doing anything else as they sit in the chair? (eating/reading)
Will this chair get dirty often? (yes/hopefully not)
Who will use the chair? What are the physical characteristics of the user(s)? (under 30 pounds/possibly hundreds of pounds)
The answers to these questions helps to dictate the design.
For the next few weeks you will act as engineers. You will work in teams to design and build a chair prototype
Distribute Lifeguard Chair Design Brief

4. Design a Lifeguard Chair
Local authorities have recently decided to open a privately owned swimming pool to the public. A grand-opening ceremony is currently being planned and the Town Safety Inspector has ordered that lifeguard chairs be constructed so the swimming pool is up to public safety code. These new lifeguard chairs must be completed before the pool can be opened to the public. You have just been hired by the Safe Stands Company to design and construct lifeguard chair models in time for the grand-opening ceremony. The chairs must be sturdy enough for the lifeguards to sit on and must be tall enough for them to patrol everyone at the pool.

5. Design a Lifeguard Chair
Criteria
Chair must be at least 35 cm tall
Cards can be folded but not torn
No piece of tape can be longer than 5 cm
Chair cannot be taped to the floor or any other object or surface
Chair must be in one piece
Chair must support the ‘lifeguard’ for 20 seconds in an upright position
Constraints
Only use the materials provided (note cards & tape)
Chair must be completed in 15 minutes

6. Problem Scoping Identifying the problem
What is the problem?
Need lifeguard chairs be constructed so the swimming pool is up to public safety code.
What is the goal?
To design and construct lifeguard chair models in time for the grand-opening ceremony.
Who is the client?
Safe Stands Company
Who is the end user?
lifeguard

7. Problem Scoping Identifying the problem
What are the design criteria (desired features)?
Chair must be at least 35 cm tall
Cards can be folded but not torn
No piece of tape can be longer than 5 cm
Chair cannot be taped to the floor or any other object or surface
Chair must be in one piece
Chair must support the ‘lifeguard’ for 20 seconds in an upright position
What are the design constraints?
Materials provided
Time

8. Idea Generation Individual Plan
Do you have enough information?
What questions do you still have?
In your design notebook, label “Individual Design” on one page
Draw a sketch of your design  Include labels, perspective, scale

9. Questions to consider:
What are examples of chairs that come to mind? 
Tables and chairs have supports to keep their legs from tilting or twisting. Look at the furniture in this room. How would you describe the supports you see?
What kinds of forces act on a chair or table?
How will these forces play a role in your design?   

10. Identifying forces on a chair
There are two forces working on a chair. The force of gravity pulling the chair to the center of the Earth. The upward force of Earth pushing against the chair.
When the two forces are balanced or equal, the chair remains still. Should one force be greater then the other, the chair falls over. These are forces acting on the chair.
When a weight or mass is added to the chair, then additional forces are considered. The force of compression represents

11. Compression vs. Tension
Identifying forces
Compression vs. Tension

12. Tension
Tension is the amount of the pulling force exerted on another object. It is the opposite of compression.

13. Compression Compression is the amount of the pushing force
exerted on another object.

14. Questions to consider:
Looking at the materials, how can you use these materials to make a chair that is at least 35 cm (12 in) tall and strong enough to hold a lifeguard (stuffed animal)?
What can you do to prevent your chair from:
Tilting and twisting
Wobbling
Collapsing

15. Idea Generation Team Design
In your design notebook, label “Team Design” on next page.
Share your plan with members of your design team.
Agree on one design. Draw a sketch of your team design and create a list of materials you will need (and cost).

16. Materials
Material
Index Cards
Masking Tape

17. Solution Production and Performance - Construct and Test
You will have 15 minutes to construct
Keep in mind:
You must follow your team design
Use only the materials provided
Note any modifications you wish to make to your design

18. Solution Production and Performance - Construct and Test
How are we going to test our designs?
Test Conditions
Place Lifeguard (stuffed animal) on the chair.
Let go and time for 30 seconds.
Record results.

19. Data Collection Team # Does chair stand on its own?
Is the seat of the chair at least 35 cm tall?
Lifeguard able to sit for 30 seconds? 1 2 3 4 5

20. Communication Share Results
What were your results?
What was the actual weight the bag could hold and the estimated volume of the bag?
Did your team’s design meet the client’s needs?
In what ways did your team use what you know about forces to inform your design?

21. Optimization Improve and Re-design
In what ways could you improve your design?
What is one feature you could re-design?
To what extent could your re-design improve your results?

22. Data Collection Team # Does chair stand on its own?
Is the seat of the chair at least 35 cm tall?
Lifeguard able to sit for 30 seconds? 1 2 3 4 5

23. Student Work

24. Literacy
Books
Toy Boat

25. Assessment