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using iMechanica in teaching Engineering Mechanics

Henry Tan's picture

New Grading System posted 

Why iMechanica?

iMechanica is an appropriate website for teaching/learning Engineering Mechanics for the following reasons:

  1. iMechanica is a community for people involved in engineering mechanics.
  2. One (instructor) - to - one (student), one-to-many, and many-to-one methods of teaching/learning are possible.
  3. Peer review and peer observation of teaching/learning is available.
  4. Instructor can be wrong. iMechanica provides an open site for discussions.
  5. Viewing traditional lecture material from different perspectives is feasible.
  6. iMechanica can give students a general view of what is engineering mechanics, which is especially important for 1st year students majoring in mechanical/aerospace engineering.


Three PhD students, Mr. Shengke Zhi, Mr. Qi Dong and Mr. Ricardo Mondragon, are hired as tutors for the tutorials.

Each week there are two hours (11-12am Thursday; 3-4pm, Friday) for lecture. During 4-5pm, Friday, 8-10 stduents are selected, based on their performance on iMechanica, to meet with tutors and the instructor. Students will be asked for questions or encouraged for discussions related to their posts at iMechanica. This also provides a mechanism to prevent plagiarism.  


PASS (Peer-Assisted Study Sessions) is a student mentoring scheme in which second and third year undergraduate students run study sessions for first year students. Students are sometimes reluctant to take their questions directly to lecturing staff, especially if the questions relate to very basic material. PASS sessions provide an opportunity for students to seek help and advice from fellow students who have faced the same problems themselves.

The aim of the scheme is to help new undergraduates make the transition to the more independent style of study expected at university, and to help them gain a solid grasp of the important foundational material covered during the first year.

PASS Leaders are senior students who have been successful in their academic work and who are employed to assist other students with their work. Student Leaders co-ordinate and lead drop-in sessions, support tutors in tutorials and workshops and facilitate students' learning on a one-to-one basis.


New Grading System posted, so ignore this section 

The assessment of the course includes two parts, one is from the laboratory (20 marks), the other is based on students’ performance at iMechanica, which is given on a weekly basis.  The assessment is designed to encourage students to learn mechanics with interests and to be creative.

(1) Weekly basis
The assessment is done on a weekly basis (this Thursday 1pm - next Thursday 1pm), self-marked and posted online by students, and checked by tutors. Each week a student can be awarded 10 marks in maximum. There are totally 12 weeks for the semester. The maximum final marks can be achieved is 20 (laboratory) + 12 * 10 (from iMechanica) = 140, however, this is unusual. A student fails if the final mark is below 56. Therefore a stduent need to earn at least 4-5 marks per week in order to be safe in passing the course.

The current criterion for fail, 56 marks, may be changed depending on the results in the first 2 weeks. It will be finalized at the end of the second week.

Below is a explanation of how marks (maximum 10marks/week) are awarded. Marks are awarded based on the points collected.

(2) Points
Point are calculated on a weekly basis (this Thursday 1pm - next Thursday 1pm). The number of points for answers/comments to posted questions are usually specified, such as in question sets. Otherwise 1 point each post. The instructor and tutors reserves the right to nullify trivial posts. 

(3) Weekly-mark
Weekly-mark is calculated based on the collected points during the week. Suppose the total number of students taking the class is N, and each student collected point p_i. Let M = sum(p_i,i=1..N). The weekly-mark for student i, mark_i, can then be calculated as
      mark_i = 10 * p_i * N / M.
For example, if the class have N=10 students, and each student has accumulated 25 points, then M=250. Every student is therefore awarded 10 marks.
In another case, if student A has 5 points only, B has 45 points, and all the others have 25 points, then student A has 5 marks, and all others have 10 marks (notice that 10 marks is the weekly maximum, as said in section 1).

(3) Competition mechanism
The above marking system involves a strong competition mechanism. If the whole class is active (therefore M is high), a student with low point (p_i) much pickup in order to get a good mark. This action will increase M and therefore decrease all other’s marks. Therefore, in this marking system all students have to be active.

(4) Continued learning enforced
The limit for the maximum weekly-mark, 10, is set to prevent the case that an excellent student may gain a high mark in just a few weeks and stop further learning.

(5) Honors
Authors of excellent/creative posts may be invited to give short lectures.
Each week, top 5 students (according to the points collected) will be listed.
Top 5 best students (according to the final marks) will be honored on the course website.

(6) Guidance to students on plagiarism and other forms of academic malpractice

Other courses taught at iMechanica
Engineering Sciences 242r: Fracture Mechanics of Thin Films and Composite Materials

Some useful lecture notes

Some references:
Zhigang: What and how we should teach in the time of the Internet and Globalization?
Michelle: We must not forget to teach the fundamentals
Zhigang: Why do people become registered users of iMechanica?
Dhruv: CALLING ALL STUDENTS! (and everyone else)
Shengke: Teaching Mechnical Engineering in iMechanica is an Engineering topic or an Education one, or even a Management Strategy


Henry Tan's picture

Am I doing a good thing of bad thing in teaching Engineering Mechanics this way?

What are the pros and cons?

Am I too risky?

David Smart's picture

I still don't fully understand how this system is going to work - we're supposed to post our answers on the website? Surely someone could just copy anyone else's answers from their post? What is the point in me posting my answers when 20 people before me have put out an (near) identical post?

I think the idea of giving the people who post the first answers more points is HIGHLY unfair! What about those who have other commitments that day, or live further away?

I admire you for having faith in our class, that they will all be honest about how many points they've scored, however please let's be realistic. People WILL lie! You can't ask people what marks they should recieve when it will contribute to their final grade for a University Degree - it's too much of a temptation!

I am personally not a fan of the competition element you've included in our course either. I know I would prefer if you set me work, I handed it, you gave me my mark. Why should my marks suffer if we have an 'imechanica addict' in our class?

All the above reasons are making me highly sceptical of this new system, and I know many other's in the class feel the same. There is a reason so many people use the traditional assement method, and that is because it works!

Lastly, could you please tell me how many points I should recieve for each post (is there a set number or will you just tell us?), and how we report our number of points to you. Do we post this somewhere on the website, or tell you in person? Is it the same number of points for completeing the exercise, as just making a random post? Do I get marks for this post!?

Please be in touch. I look forward to you response Mr Tan.

Henry Tan's picture

Dear David, many thanks,

As stated in the Tutors section of the assessment ( Plagiarism will be prevented by the Tutor System.

The author of the suspected post will be asked for explanation of his/her post. This will provide a mechanism to prevent plagiarism.

Henry Tan's picture

Good point on the competition mechanism I proposed. Actually I am not satisfied with this either.

Is there any better way to encough students learn more and be creative, while still can prevent the so called 'iMechanica addict'?

Henry Tan's picture

As said in the Assessment/points ( section. The instructor and tutors reserves the right to nullify trivial posts. Actually I will delete random posts.

Henry Tan's picture

According to the current rule that I proposed (, 1 point to your post. However, I believe that is not fair because you posted very good opinions.

Can somebody suggest a more fair method for giving points? Thanks.

Frankly I agree with Dave, that there is no feasable way for this kind of method to work. Most students are used to the standard:

 -Be taught in lectures.

 -Periodic testing of knowledge recieved in lectures through examinations and other work which also allows for further reading outside of knowledge presented in lectures.

 -Final exam to test all knowledge aquired throughout the year. 


You keep saying how you want the course to be more involving and creative than other courses, it's the lectures where you can get creative, involving the pupils in whichever way you see fit. However, judging from todays lecture you have alot of students in your lectures as you said yourself, and so involving students fairly would be very hard to do.


Personally I seem to cope well, and somewhat enjoy more typical ways of learning as mentioned above. Also, you've set a question on cross products which many people, myself included, wouldn't have covered yet as we have only done M1 at A level, if that, and so many people will not be sure how to approach these questions. I know we can find out in other places, but it sort of seems like the kind of thing that should be taught in lectures as it's pretty basic and necessary stuff. You also mentioned about Q2 that "Newtons Law isn't that simple", but yet provide no further explanation. What everyone has done is used the knowledge we acquire at A level to tackle the problem, and from what i can see generally 100% accurately as far as we are aware. If, like you say, Newtons Laws aren't that simple then this again are things that should be covered in lectures ideally before setting questions on it. Also, as far as i'm aware we aren't using Newtons Laws to solve that question but rather SUVAT equations, which to my knowledge didn't involve Newton, but i could be wrong.


Hope most of that made sense, Richard. 

Henry Tan's picture

I will explain why I believe the Newton's law is not that simple, or easy to understand. I have more to say than in the traditional books. I will lecture that today afternoon 3-4pm, Renold/C2.

 I think David is right and I agree with him, because it is not a good method of teaching and we all are used to the traditional method as mentioned before. In my opinion you can plan tests and quizzes on the WebCT like every other course and provide us with this kind of forum to discuss our problems, but the discussion should not be marked only the tests and quizzes should be marked. We should also have an exam at the end of the semester, as the point system you devised is quite insane and doesn't have any thing to do with the understanding of the subject matter. It simply doesn't help students to go to a blog and write something and get points.

Although I prefer the traditional method of teaching I can see the aim of looking for a new method. However, I don't really believe this to be a suitable way for many reasons. I do not want to repeat my views as most have already been mentioned by others but being the first to answer would have been impossible for me today as I had to leave university after our lecture at 12:00 and head straight to work. Therefore I had no access to a computer until at least 8:30 this evening! 

Henry Tan's picture

Good post that let me know what's your concern.

let's talk about this in the second hour of today's class, Renold/C2.

Henry Tan's picture

The class will start from next week. Tutors are needed for this course. We have around 170 students with more than 8 tutors last year.

I am planning to hire 4-5 tutors from The University of Manchester, and 3-4 tutors internationally. Home tutors will be paid with the current University policy. I will request the School and the University to pay international tutors.

I will also apply for funding support from the Royal Society, Royal Academy of Engineering, EPSRC and other UK higher education systems. In this way tutors may will paid quite high.

I taught similar courses in US and China, therefore, international tutors from those areas are especially encouraged.

Henry Tan's picture

In British English, a tutor is usually a postgraduate student assigned to be a teaching assistant. TA is the equivalent term in the United States.

If you are interested to be a teaching assistant of this course, please reply this post. The class will start from 27 September. The major responsibilities of the tutors for this course are to maintain online interactions with students.

Alan Tan's picture

Hi Prof. Henry Tan,

I am interested in this post and I hope I will be able to help students learn.

Sincerely Yours,


Henry Tan's picture

The goal of The University of Manchester is to be the world’s top 25 in general.

I aim this class to be the world’s #1 in teaching Engineering Mechanics. Students should benefit a lot from attending this course.

Temesgen Markos's picture

Hi Prof. Tan,

Can you add details to the job like how many students a tutor may interact with, an estimate of the amount of time per week/day it may require, the minimum qualifications and suject area required, the reimbursments and how international pay out going to be handled, if you want people to email you with credentials or simply express interest etc...

I am thinking about it but I need to know those details to decide.


Qi Dong's picture

It is a very good idea to teach Engineering Mechanics using iMechanica. Students may not be interested in the traditional way in learning Engineering Mechanics, and they do not like the examination at all.  Teaching Engineering Mechanics using iMechanica will help students learn more knowledge than they can get from classroom, get the recent information and have an international view in this area. Students can learn knowledge and do their tutorials more flexibly.

 I am very interested in the grading program proposed by Henry, which could be an innovation on the traditional examing method. Students will be happy to see this than the others, as they can pass their exams more flexibly and creatively. Looking forward to seeing Henry's final grading program and wish teach Engineering Mechanics using iMechanica well.

Henry Tan's picture

I was told today that the University can only pay for in-house tutors.
However things may change if there are many posts from outside.

Anyway, I believe that it is fun to join in the discussions.

Henry Tan's picture

With the latest iMechanica member, Ricardo from The University of Manchester, the total number of the registered members has reached to 3635.

With more and more mechanicians joined in, and wide range of topics covered, iMechanica is becoming the best place for teaching Engineering Mechanics.

Henry Tan's picture

Comments for the current assessment method are invited.

I appologize if I seem negative or pessimistic, but reading the above posts, I have noticed that these posts are more of a bulletin board rather than a conversation. For example, one student (Mr. Smart) commented on his views of this new system, after his post (which includes clarification questions) 9 posts have been put up, and yet no one has answered or even reflected his point. On the contrary, it almost seems to have been avoided, as there was then a conversation relating tutoring.

My main point however, isnt about answering Mr. Smart, but is to ask for awareness: to learn something, I have to encounter things of which I have not met before, be clarified of them, and then practice with my new knowledge. I understand the innovative and interesting ideas for making  iMechanica the basis of our teaching, except for learning. i can understand it being used for practice and/or clarification of new information. But unfortunatelly I do not understand how I will be taught through it. Today, the vector and kinematics questions count as practice, as I had already encountered the material and been clarified of the method applied to the material. But if I was to attempt a question on something I have not yet seen, i do not understand how being the first person to post, and/or debate the topic will make it easier for me to understand the subject. I also understand how iMechanica is an easy access for socializing with colleagues, but again, I do not see how that will make me more able to understand physical conscepts.

I would like to appoligize if this post seems negative, I just wish it would bring awareness to my view and it wouldnt be ignored.

Thank you very much,

 Rafael Moraes

Henry Tan's picture

very challenging opinions to me. I will answer you soon.

Henry Tan's picture

You will learn mostly through my classroom lectures, the lecture notes and references that I will post for each class.

The class website at iMechanica is a tool to practice the knowledge learned and to stimulate learning. If you miss the chance to be the first for question n, there is always question n+1 waiting for you. And the best is to comment on other’s solution, trying to point out the mistake/error, or find out other ways for the solution. There are lots of problems in Hibbeler’s web as the link is provided in

i understand the idea of always being a new quesiton: n+1 is always available...or is it? Is there a specific question for each student, so is 1<=n<=170??? and even so, people who have the chance to reach a computer sooner that the others can answer more than one question...taking up other people's chances of answering first, still being unfair.

 Another dilema, is as u state, there are too many people for you to control and assess each of our works... but u have to read all of our posts technically, its just a more interesting way to do the same checking. lastly, i still do not understand how commenting on people's answers will prepare me with the core basic mechanics which i will use in my 3rd and 4th year of university.


once again, i appologize if i seem too negative and pessimistic. 

Henry Tan's picture

Dear Rafael,

I have noticed the flaw after reading the survey and all the comments online.
New grading policy is coming to

  1. ensure students learn everything lectured in the class, and
  2. encourage more after class self-learning.

I noticed that you commented a lot to improve the teaching, which I really appreciate.

Thanks, Henry.

1. I suggest that a specialized system/website be set up for questions and certain topics, that only allows a user to see other people's posts after they themselves post answers. That way, everyone has a chance to get points from the question/topic. This should reduce plagiarism and encourage students to try the questions themselves since they cannot see other opinions and discuss it till they at least give an answer of their own. The moderators will still need to see if a student just puts a useless post to see other people's posts, and not award points for those. This will help set a "bare minimum" for students to get slightly above average marks if they finish just the work provided, and still maintain the reward for "going the extra mile" for others who participate more and dig up facts from the resources and opinions on iMechanica by themselves. Only truly lazy students who don't bother to try commenting won't benefit from this. I don't know any coding so to make this website/system, so we will require some one else's help.

2. A more subjective point scheme might be better. Where a post can get a maximum 5 points based on content (plagiarism is avoided by following suggestion 1) Anybody who posts valid points get 3 marks and those who managed to get several very good points get 4 and very outstanding points get a 5 (this is just an example of how it might be graded). This will take a lot of effort from moderators and is just a suggestion.

 3. A more official way of keeping track of points is necessary. It can be incorporated into the specialized website/system.

 4. There should be more specific sections for 1st year students, 2nd year students and so on so that we can find posts related to us (like questions and topics for our level, if we are maintaining it on this site) easier as I see a lot of posts that are too advanced for us freshies (I am a 1st year Mechanical engineering student) and I find it difficult to find posts that we can constructively comment on. Of course access to other posts will be avialable but that will be only for further knowledge's sake.

Another suggestion would be to follow the 3rd option on the survey we took on Friday. Which is to still maintain part of the old system (i.e take an exam) but still using the new system since by just throwing the new system at us in it's current unrefined form is risky and it has gained a lot of opposition. As Mr. Henry Tan mentioned, this is the first time this sort of system has been implemented so some tweaks will have to be made.

 Just to summarize what I do understand about the system:

1. All the main teaching would be done during lectures (just like the old style of learning. iMechanica only provides questions and topics for assessment, the notes (and other resources) as well as discussion.

 2.  There is a limit to the marks gained per week that will prevent any "iMechanica addicts" from scoring over the top. Despite an addict or two, if your participation is around the class average or slighty better, you still get 8-10 marks at the end of the week.

A few pros of this system (of the top of my head):

1. We now have a worldwide support group for our Mechanical Engineering. Ask people from different uni's their opinion for topics.

2. We now have access to a lot of cool facts and applications of mechanical engineering (I was watching the talcum powder patterns when an iron plate vibrates at diffrent frequencies. Fascinating. Wouldn't have known about it without the site.) Text books do not update in real time.

3. We can avoid a "shout-fest" (unless 2 users are immature enough to post one sentence flames at each other). I do not know whether it will happen around here but sometimes a verbal discussion degrades to everyone just jumping to defend their own view the moment they hear an objection. Here, it is easier to see some one else's point of view when it is typed out because we get to reread  the person's comment and we need to think before actually replying.  

Personally, I am quite willing to try this new system but I believe there are still bugs to work out if we are going to make it an effective teaching technique. So far, I have mostly seen posts on "why this system will not work" so I am trying to post something on "how we might get this system to work". 

 Whatever the final outcome, whether we keep this new system, revert to the old one, integrate both or some other option is taken, I give my support to Mr. Henry Tan for trying to be innovative.

 P.S I know the topic for this thread is pro and cons but I am not sure whether there is a thread for suggestions. Sorry if this is in the wrong thread

Henry Tan's picture

Thanks for many good comments (I would like to give you many marks for this post, however the newly updated Rule of the Game would not allow me do that).

To the 2nd suggestion:
I will propose a new grading policy this afternoon. I will seek students' opinions before I put it in Thursday's class.

To the 4th suggestion:
Actually the good thing for iMechanica is that everyone has the right to set his own Blog! You definitely can initiate a 1st year student Blog! I will surely encourage you to do that, please be the FIRST!

Henry Tan's picture

Who would volunteer to setup a 1st year student Blog (Mechanical/Aerospace)?

You will be the first in iMechanica in doing so. References:

Henry Tan's picture

New Grading System posted, please comment on it! Thanks.

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