Taking Time to Reflect on Learning in MITx

Last week, I decided to return to practice problems in week 1 and complete some of the problems that I did not have time to finish. (Each week I do as many practice problems as I can until working on the homework is all I have time for.) I was happy to see that I could answer these problems (which were about node analysis and voltage divider circuits, two relatively basic concepts) without too much difficulty. I am learning, I thought to myself. I need to spend this time going over what I have learned and making the abilities my own, so to speak. In MITx I am always pushing ahead as diligently as I can and not spending time reflecting on my learning.

The designers have been changing small things in the course. It's interesting to see the changes, such as making the current text in the transcript bold when it is spoken in the video. The word "SPEED" now appears next to the buttons for changing the speed of the videos. Other students make suggestions for changing the interface or adding an interface for mobile users. Not me--I'm usually coming from behind…

Which reminds me: three cheers for Wolfram Alpha! When I needed to compute derivatives for the incremental analysis, I only need to type the equation into the computational engine. (My calculator is not good enough for this.) Students were suggesting a variety of tools--such as a math program you can download from Microsoft.

Still, you know you're in deeper waters when you can't solve the problem on your calculator that was sufficient for any other class you've taken. I'm uneasy that I'm avoiding brushing up my calculus--who am I kidding?--whole new coats of math are needed here! I was able to get a decent grade on the homework, but left the last problem untouched because I could only get through half of the lectures for the topic. I am starting to feel the effects of not having the prereqs. I wonder if MITx will have to enforce a certain prior level of knowledge before letting people take a course. Surely I'm not the only one with these problems...but for the moment this may not be a main concern.

The first exam was announced: it will be in the last week of April, and we have 24 hours to complete it once we begin. I've already marked the calendar and told my wife--who, by the way, did a bunch of my chores to give me time to complete MITx work.

Completing Labs in MITx: Thank Heaven for Trial and Error

Well, I solved Lab 3 with help from my wife and a hint from the discussion forum, and some late night persistence. In this problem we needed to build a series of digital gates that are connected to three voltage sources. Professor says an Intel chip has a billion gates, but our lab involved three, so we start small. Really small.

In Circuits and Electronics, we must complete a weekly lab, an assignment in which we must build a circuit that satisfies certain parameters. Part of the assignment involves getting the appropriate configuration of resistors, wires, and other elements, and another part of the assignment means getting the right values for these elements. It’s a rather safe way to do a lab in basic electrical engineering; I know the only shock I’ll receive is how many times I get the answer wrong.

A lot of my problems with this lab were due to my own ignorance about how to use the circuit sandbox. First, I did not know that you could cross wires in a diagram, which, it turned out, was necessary for the solution to the problem. Of course, crossing wires is acceptable because in an actual circuit, a wire can go over or under a different wire. In my crude diagram, you can see that the red voltage source (the circle) needs to be connected to the red gate (the diamond), so the wire must go over the other gate. I finally found a discussion posting that mentioned that you can cross wires, but another person said that this is in the directions in how to use the sandbox, so I’m to blame for not reading all the directions….One weakness I have is that I am spending more time trying to understand equations than trying to understand the common-sense rules for putting these things together.

But a funny thing is that I was able to get the correct answer by using trial and error to determine the resistance values for these gates. This seems rather unscientific to me, but one hour before the deadline makes me happy for any advantage I may get. And yet, wouldn’t a situation in an actual lab be much much different? For example, at one point, I put the resistance value of a MOSFet so high that I shorted part of the circuit. Now, in the sandbox, who cares, right? But surely this kind of guessing could be dangerous in a real circuit.

One thing I don’t like about the circuit sandbox is that I use “backspace” to delete elements after I’ve selected them. If I hit the button more than once, I go back in the web browser and lose my circuit.

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.

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.