Chair Project
In Engineering 1, you were challenged with creating a tall, stable tower out of newspaper or spaghetti. Today, you will be challenged with a similar problem of using 'weak' materials to create a stable structure. The difference? This new structure must fully support a student for 3 minutes.
OVERVIEW:
Corrugated cardboard, made from a natural renewable resource, has one of the best environmental records. In 2002, more than 23 million tons of corrugated cardboard were recovered and recycled in the US – that is 74% of all cardboard produced in the same year. Cardboard has the best recycling rate of any packaging material used today. A hard look at every scrap of cardboard can lead the creative mind to see it as a valuable raw material. This is your opportunity to discover the potential of corrugated cardboard.
Design: Urban Nomads
The Challenge: Design and build a cardboard chair that will comfortably support an “average” middle school student. The winnig team will be decided on style, functionality, and, in the event of a close race, weight effeciency ratios (#person / #chair = effeciency)
Criteria:
You prototype AND final design must...
Be made entirely out of cardboard and glue.
Glue of any type is accepted.
Have a seat and a back.
The seat of the chair must be at least 16” from the floor (measured to the bottom of the seat).
The top of the back must be no less than 30” from the floor.
Be portable (able to be carried through doors).
Be comfortable to sit in
If any of the above criteria are not met, your design will be automatically disqualified
Constraints:
Your prototype must stay within these (above) limits...
No painting or coloring of any kind!
No metal or other fasteners are permitted. (Such as staples, nails, screws or tacks)
Materials:
• Cardboard
* Box cutter/utility knife
• Glue
NOTE: Keep track of and safeguard all materials. Points will be lost if replacement parts are needed.
Safety: Read and take notes HERE
To Remember:
The strength of any material can be increased or decreased by changing its form
Weak materials can be strengthened through folding, creasing or other modifications
Load distribution is key in identifying areas of potential weakness
Key Terms:
Aesthetics: pleasing to the eye
Beam: a supporting member that transfers weight from one location to another.
Center of gravity: the single point in an abject that gravity pulls on.
Compression: a force that presses or pushes towards an object’s center.
Ergonomics: the practice of designing objects that conform to the dimensions of the human body to maximize comfort.
Load: weight that is carried by an object.
Strut: a brace or support.
Sway: to move back and forth.
Truss: a triangular support.
The Competition:
Chairs will be evaluated by having other students sit in them and vote to determine which design is the most comfortable and “cool.”
The Calendar HERE (to help you plan your time management)
Chair Parts:
(consider which are NECESSARY and ACHIEVABLE for your project)
Technique Tips:
- Making a Sturdy Chair Keeping in mind that your chair will fail at its weakest link, you should make slots that will not allow movement of any of the members (parts) as they sit in the joints.(Joints are where members are joined together.)
- You should try to cut all slots carefully so they are straight,parallel, and the exact width of the material that will fit into them. Many chairs fail from unwanted swaying.
- Not everyone will sit on your chair where you planned. For example,they may sit on the front edge rather than towards the back of the seat. This would put a greater load on the front columns, requiring them to carry a load that would have been distributed among several columns or other load bearing members. Therefore, it is useful to plan your chair for the person who may not follow your instructions about where to sit.
Building Step Ideas:
Break into teams of 2-3 people. Be sure that you are with someone you can work well with. Remember, I grade you individually AND, for this project, you will also be grading each other!
Pick up a packet from the Eng2 basket and begin. Each page represents .5-1 day's worth of work. DO NOT RUSH THIS!! There are a lot of places for this project to fail! **Be careful**
Make sure someone responsible in your group holds onto the packet. Lost packet=start over :(
TESTING CONDITIONS:
1. Each chair will be weighed and the weight will be recorded.
2. Each team should identify a “tester” prior to arriving to the competition. This person will be weighed and the weight will be used in the structural integrity formula to determine the chair’s efficiency. (High/big numbers are best!)
3. The tester will carefully sit in the designed chair; as previously tested. The weight distribution on the chair should be a design issue/consideration for each team.
4. Once the “tester” is comfortably seated in the chair, the timer will begin. If the chair withstands the allotted time(3 minutes), your chair is then compared by the weight.
5. “Comfortably” seated is defined as the tester being seated in the chair and leaning against the back of the chair and resting. There will be no sudden forces acting on the chair; just one constant force and weight throughout the three minutes.
6. The chair with the highest efficiency will receive the maximum 25 points. The chair with the second highest efficiency will receive 20 points. The chair with the third highest efficiency will receive 15 points. This pattern will continue until 0 points is reached or all of the chairs have been evaluated.
7. Any chair that is not successful will not receive any points for the function category.
TEST DAY RUBRICS:
See your packets for the process rubric, peer rubric, and test day rubric.
JUDGING
A team of judges/teachers will conduct individual evaluations of the designed chairs.
These individual scores will be averaged to determine the overall winner.
ALL DECISIONS MADE BY THE JUDGES ARE FINAL.