Where's the show-your-work-for-partial-credit button in MITx?

I stayed up late on Sunday trying to complete the second lab, which--how do I explain i?--involved building a circuit with a set of resistors that produced a certain maximum and minimum output voltage. At one point during the day, I had posted a question in the forum about a concept involved in the problem (the concept of superposition) and some nice people directed me the textbook to read more about it.

But I also came across an answer that included a link to another posting that, I assumed, discussed the concept in more depth. Well, it included a possible answer to the lab. This is another difficulty I have with MITx: avoiding posts that include explicit answers while I am looking for guidance on concepts. I can't unsee those answers, unfortunately.

The Honor Code forbids the posting of answers to graded assignments, but people still post these things. Sometimes people post equations that include every step for solving a problem and only leave out the answer. Really, as a participant in this class, I must keep my own honor code and be judicious when I consult the discussion forum for help with concepts. I phrase questions to make it clear that I just want help understanding a concept.

So my dilemma was whether to use the information I saw--which I would not have understood on my own--or go back to trying the lab by myself. After my poor wife stayed up trying to help me, I decided to give up and take the 0. They drop the two lowest lab scores anyway.

Still, this got me thinking about how MITx does not allow partial credit. I had tried out several different possible answers, and was able to get the correct minimum output voltage. Shouldn't that count for something? The circuit is either correct or incorrect. Perhaps this is a feature of large, free online courses: there aren't the teachers who can scan through thousands of answers to see if the answer deserves partial credit. But I can't help but wonder why it is helpful for students to get a perfect score on a lab or no points at all. Could the labs be broken into several steps in which students could receive credit for completing part of the system correctly?

Today, I looked up the answer to the lab and then posted a question in the discussion forum about the circuit diagram. In ten minutes, I had received two answers from people, and I think I understand my mistake now. And this is what I wanted all the time.

Week 2 in MITx: Feedback in the System

So homework 2 has proved to be quite a bit more difficult. There is no easy question like there was in the first homework. Now I must apply the Thevenin Method to solve a circuit with input and output voltages. Never did I think turning on the light could be so complicated (it actually is probably a simple circuit). Today, my iron broke and I briefly thought about trying to take it apart to find the problem. But I'll probably just get to Target for a new one.

What is the best kind of feedback that you can receive in a massive online course? Lately, I get the red "x" a ton as, there's no denying it, I have a harder time in the class. (Reminder: your answers are assessed immediately by the system: green check means yay!, red x means grr.) The red X propels me to keep studying…I try to think of it as x marks the spot you need to study more.

Feedback has been studied extensively--a significant meta-analysis of feedback was published in 2007 that indicated that cues had the highest effect size. Simple praise had a very small effect size. And feedback about a correct answer had a greater effect size than feedback about incorrect answer--this is particularly difficult feedback to get in a large online course in which I sometimes don't fully understand the answers I'm getting.

The research says to seek out cues, and I could use more cues in my work in MITx. I seem to be able to find them by consulting the discussion forum at just the right time, with a posting that does not give away the entire answer.

More thoughts about peer tutoring in MITx. I posted my first question (about how to identify parallel resistors) and shortly received several responses. In the system, I was able to choose the correct answer--and I was gratified to see that I could choose more than one correct answer. This system of allowing people to accept answers helps to close discussion threads that might continue even after they are useful to people. Being able to accept more than one answer shows that MITx values multiple perspectives and different ways of explaining a concept.

MITx Homework 1 and Lab 1 are finished. Whew.

his weekend I finished both the first homework and the first lab, and I received perfect scores on both. This was not without a lot of work, and several late nights while I scoured the textbook, scribbled circuits and formulas all over sheets of paper, and checked the discussion forum for hints on ways to solve the more difficult problems. Just an hour from the deadline, I am starting to see posts from people who want others to post answers in the discussion forum. In response, the staff or other users with enough karma points are closing those threads or reminding people that homework answers cannot be posted in the discussion forum.

Just a reminder: in MITx, the homeworks are online. When you solve a problem, you type the answer into a box, press the "check" button, and--if you're correct--you see a green checkmark beside the field. Some problems are so hard that I do small dances whenever I can get that green checkmark to show up. Most of the time I get the red X, which means, "Try again." The problems have several parts, so you need to get that first answer correct so that it can be plugged into another equation and then your answers fall like dominoes (well, like slowly falling dominoes).

I am grateful, most of all, that the course (so far) has not required any math that is more complicated than algebra. If anything, the problems are hard because you develop a lot of independent equations for different variables (voltage, resistance, current) that you can solve for by a process of substitution. The homework took me a long time--at least 5-10 hours over several days, I think. A lot of my learning seems to happen in the constant process of trial and error--coming up with equations, solving for values, trying out the result.

I have learned that one weakness in the system is that I have gotten several answers by just changing the sign of the value I entered in the box. For this reason, I am still pretty weak on identifying whether currents associated with voltage sources are positive or negative. I have changed x to -x and gone from wrong to right, but I still don't know why I was wrong the first time.

I find that I do get many of the equations or heuristics for solving circuits from the lectures or reading, but the discussion forums contain nuggets of information that I need for solving questions. I look for posts that contain a possible way of thinking about a problem without actually solving the problem. That is hard because part of me just wants the answer.

I am holding my breath that I can continue to succeed despite not having the prereq--I fear that Coulomb's law and electric fields are stalking me in the magnetosphere. But the assumptions of the lumped matter discipline have created a "playground," as the professor calls it, that make things simple (though not easy).

When I checked my grade, I saw that I have earned 3% of the final grade. That 3% is going to be polished and put in a case.

Creating My Own ZPD?

How hard it is to not just look up answers! In the practice problems, there are links to the discussion forum where people put up the answers to people's questions. Today I was working on a problem involving Kirchhoff's laws, and I was unsure about the sign that should be applied to a specific voltage for different elements in the circuit. I thought I'd go to the forum and read about signs of voltages, but the page I landed on had the answer front and center. I tried to look away--was that the answer I saw? It was. I put it in and it helped me think about the rest of the problem--for which I needed to keep myself from looking at the rest of the answers.

I did see that one of the T.A.'s posted a response asking people not to post answers in the discussion forums. And by the way, there are some really smart people posting answers; I wonder how many people taking this class have already passed a similar course at another institution.

After seeing the answer I returned to the problem, and began trying out answers. Eventually, I went back to the textbook and read about how to assign the correct sign to a voltage when I am examining elements in a loop. This gave me the key I needed to answer the rest of the questions about how to solve for different elements in the circuit.

I know that some struggling is part of the learning--necessary for keeping that development moving along, to crudely paraphrase Vygotsky. But in MITx, I know that the answers are not far away. It's as easy for me to find the answer as it is to check e-mail. With some fortitude, I was able to figure out the rest of the answers. This makes me think about the zone of proximal development and how this zone is defined in activity when my "more knowledgeable peer" is the online textbook, or a post in a discussion forum. The particular difficulty I have is determining exactly what I don't know, or (in other words) my potential level of development and the right activities for developing a conception that is closer to my potential level. In MITx, I am painfully aware of my actual level of development and am grateful for the tips

How is my understanding of circuits changing--I am learning more about resistance and the different kind of elements within a lumped circuit. It really is simplified by Kirchoff's Laws that turn circuits into junior high math problems, provided you can figure out where to put the sign on currents and voltages, which I am learning to do, though very slowly.

Into the First Unit

It's amazing how far I can get by understanding basic relationships in equations. Such as, I have no idea what a linear resistor, but when I'm asked to identify a graph of current over voltage, I know that an independent current will only have one value on the y axis. I find that this kind of deduction is getting me by quite well so far. So far the equations I'm using are linear expressions, thankfully. One smart thing that MITx does: they demarcate the video lectures according to where there is a question that I'm supposed to spend time thinking about. For example, the professor has an empty graph and asks me what I think a relationship will look like. The video ends and I'm supposed to start the next one when I'm ready to go. Below each exercise is a link to a discussion forum where I may post questions or read answers to other questions. Please note: open these links in a new tab. These discussion forums are really helping me understand the concepts behind power entering a circuit. Did I also mention that I'm very aware of my point values, how many points I do or don't have? When the professor was recording his lecture, his dog was barking. I can't say why that makes me feel better about this class: if he has a dog, he probably tolerates people that make the same mistake over and over.

My progress on MITx: Lab Tutorial

Today I worked on the lab tutorial in which you practice using a tool that lets you build and test circuits. It's a point-and-click interface in which you drag and drop things like voltage sources and resistors. The cool thing is that the system tests the circuit and displays the values of resistance. I don't really know much about circuits, but I was able to build the one based on the copy that the system provided. Currently, my conception of a circuit is that it is a device that supplies electrical current to a simple or complex machine, but I may be very wrong about that. I found the total resistance and the current flowing from the positive to negative.

The next few problems in the lab tutorial seem harder, and I will likely take a while to answer them. I have noticed that there is a lot of help in the discussion forums, if I can find the right answer to my question. I have gotten better at using the labels to find answers. (Although sometimes someone posts something weird, such as a question about why the Apple store is down. The moderators shut that one down pretty quick.)

On a side note, I recently received the badge of "Teacher" because I answered someone's question about the function of the check button. This seems more like a "Teaching Assistant" function, but I find myself pleased to have received this acknowledgement. Also, it is nice to help someone else who is working on the course.

While I'm doing this, I keep asking myself what I'm learning, and so far I think I'm learning more about how to operate the interface. Of course, this is very important.