The basic idea of this course is to teach students basic mechanical design. They will start by drawing upon simple physical concepts, then learn about different mechanisms, then go on to design a machine or structure of their own.
Maths is to be minimized, design emphasized. Something should be designed and built *every lesson*, even if very simple, so that students get used to the design process and working with their hands. For example, for the 'torque' lesson, students could build very simple lifting levers or catapults with just pencils and cardboard.
Practical, rule-of-thumb concepts will be introduced from the beginning. Of particular emphasis are the Saint-Venant principle (3-5 critical dimensions), inefficiencies, sine errors (okay, so a tiny bit of geometry for that), shear stresses & moments. This is the other reason that students should be building every lesson - the only way to make these rules-of-thumb second nature is to continually be encountering the problems they are designed to overcome.
Students will be asked to identify mechanisms and properties in everyday life that correspond to the ones they are learning about. (e.g. bring something low/high friction to the next class, find something that uses leverage)
The only on-paper process that will be emphasized is force diagrams. Students should be asked to draw force diagrams every single lesson. Visualizing a system in terms of forces is the most important thing they can get out of this course!
The formal design process will be introduced from the beginning. The curriculum starts out with a CCB workshop, which will be referred to in the building exercises in the rest of the lessons.
At the point where students make their final designs, the design process will be broken down into more detailed steps. Students will practice visualization by making sketch models, and will use their new-found knowledge of mechanisms, structures and design rules to identify critical problem areas that they need to run tests on before building a final design.
I have included a list of “optional modules”. These would be included in the curriculum as reference for the teacher, but don't have to be taught unless they are relevant to the projects that students choose. For instance, if students were designing a piece of machinery that's handled a lot by people, ergonomics might be useful.
1. Design Process (creative capacity building)
2. Springs
3. Friction (introduce inefficiencies)
4. Torque, Conservation of Angular Momentum
5. Linkages
6. Gears
7. Force diagrams, structures activity (introduce Saint-Venant)
8. Building structures (withstanding torque/shear forces. two separate lessons?)
9. Bending beams/beam cross section stiffness
11. Linear Sliders (reiterate Saint-Venants)
12. Motion conversion (reiterate inefficiencies)
13. Bearings, shafts (introduce tolerancing, misalignment, sine errors)
14. Gearboxes (bending beams, saint-venant, tolerancing, force diagrams)
15. Belts & Pulleys
16. Design Process: Brainstorming
17. Design Process: Sketch Models and Presentation
18. Design Process: Identifying problem areas and bench-testing
19. Build Machine: Identifying Materials
20. Build Machine: Tolerancing, Sine errors
21. Build Moar machine!
Note: could include a bunch of optional mini-lessons depending on what projects people are doing. These could be:
etc etc
Discussion
I'm going to re-iterate what I said about browsing to pick lessons that to fill needed knowledge gaps. I've looked through most of the lessons in this curriculum now, and it seems there's a lot of great information there, but you dont really need all of it to begin building something. If I were working on something like this, I might want an overview lesson that goes over all the different kinds of bits and pieces, so I could then figure out what I wanted to use, and then get the detailed information about those things. (Hmmm…looking at these things, I think a spring would be useful here, ok what kind of spring do I need? oh, I see, spring constants, well I guess I need one strong enough to….) I guess going about it in this order works less from a learning about energy conservation and other physics point of view, but I'm taking more of a 'let's do engineering' viewpoint, and a 'lets get to doing USEFUL things quickly'
That was rambly. Sorry.
consistent between people, or consistent for one person?
It would be really good (I think) for students to identify what additional knowledge they might need for their projects, and even have them browse lessons on PENed to find those that are relevant, and they'd therefore like to do. (Teachers can be involved in this as well, but identifying what your knowledge gaps are is a valuable skill, so having the students have a go at it first seems sensible)
Re force diagrams/omegataucurves, I think it's most important that there's a consistent intuition involved, no matter what that intuition is :p
Whoo! This looks awesome!
Something re: your comment in the chats, I think it's worth realizing that much of our excitement about ways of building intuition (ie force diagrams) is partly personal preference/ability. I know this is true for me with omega/tau curves.