Chair Design8th grade project

Written bySony Gala

Problem• Students will use the engineering design

process to design and build a cardboard chair. The teacher will sit in the chair for at least 90 seconds.

• Final products:

–Engineering design portfolio (need not be typed)

–¼ scale chair

–Cardboard chair

Requirements

• Students will work in groups of four

• Assign each member a duty– Member Name - Design Engineer– Member Name - Document handler– Member Name - Researcher– Member Name - Material handler

• Decide on a group name – relate to the project (ex: CardChairs R Us)

• Requirements:• 2 sheets of cardboard ~ 7’ x 3.5’

• Chair must have a back

• Seat of chair must be at least 18” off the floor.

• Constraints:• Students will not use any form of adhesives to build the cardboard chair

–No glue, tape, staples, nails etc.

Center of Gravity

A structure remains standing only if its center of gravity is directly over the perimeter of its base.

Center of Gravity

Loads and Joints1. What is a load?2. What is the load on a chair?3. What is a static load?4. What is the static load on a chair?5. What is a dynamic load?6. What is the dynamic load on a chair?7. What are joints?8. How can one take care of weak links?9. Why do most chairs fail?

10. What does orthotropic mean?

11. Give an example of orthotropic material.

12. How would you cut cardboard?

Orthotropic Material

1. What does orthotropic mean?

2. Give an example of orthotropic material.

3. How would you cut cardboard?

• Research – Go to the Cardboard chairs websites from Ms.

Gala’s website.

http://www.rockdale.k12.ga.us/personal/sgala2/8thgrade/default.aspx

• Watch video• Read about cardboard chair designs

– Google image search on cardboard chairs– http://www.pbs.org/wgbh/buildingbig/lab/

materials.html

Alternative Solutions• Each student in a group sketches

three chairs you may have at home or school.

• ex: dining chair, sofa chair, office chair, deck chair, lawn chair, etc.

• Think about form, comfort, looks etc.

• Sketch ideas for cardboard chair.

–Use graph paper

(copy definition)Orthographic Drawing – sketches made in two

dimensional views. Objects can be seen from the front, top, side and back.

Measure your classroom chair (inches)– Fill in the chart provided. This will give you an

idea about chair dimensions.

Standard Classroom chair Length Height Width

Back of chair

Chair seat

Legs or base

Your Cardboard Chair Length Height Width

Back of chair

Chair seat

Legs or base

Plan on measurements for cardboard chair (inches)Fill in chart.Convert all measurements to ¼ scale. Divide each number by 4. Write ¼ scale number in parenthesis.

Final Design• Use graph paper, ruler and pencil

• Orthographic drawings – front view, side view and top view

• Show measurements

18 in

ches

Scale 4” – 1”

¼ scale chairs

• Refer to the orthographic drawing

• Use one sheet of poster paper

• Draw and cut out patterns to build a ¼ scale chair.

• Remember no adhesives or attachements of any type

Full Size Chairs

• First draw patterns on the cardboard sheets

• Minimize use of material

• Use gloves, base cardboard mats and box cutters

• Score cardboard to make sharp folds

• Cut slots that are straight and parallel to make tight joints