Ahhh! The semester starts in less than a week and I still haven’t decided how to deal with labs in my Physics Optics course. I’ve taught two fully SBG (standards-based grading) courses, but neither had a lab attached. I wanted to use this post to help me flesh out some ideas I could do. Note that I’ve brainstormed a little about this already.
Individual labs
I’m really attracted to figuring out a way to have each student do their own lab. Unfortunately, I only have 3 sets of equipment with 8 people in the lab. I’ve kicked around the notion of an “I can be a good lab slave” so that they’re motivated to help each other when needed, but I’m not sure that’s the best use of their time.
So here’s how I envision this working:
- Students are given the ? number of labs they’re expected to do this semester
- each one will be tied to particular chapters, etc
- students are randomly assigned to jobs for a given lab day
- researcher (they get to “do” a lab)
- helper (they’re the slave to a researcher)
- ???? (here I’m thinking that they could be planning a future lab – maybe that’s a prerequisite to being a researcher? Or maybe they don’t have to come? Or maybe they can spend their time on a formal write up.
- Note that it’s a 3 hour period and some of the labs really shouldn’t take that long for data collection. In fact, maybe I can think of each lab period being 2 1.5 hour periods so only 2 people wouldn’t get to be a researcher. I guess I’m stuck on this point.
- The lab is set up and data is collected. They can use their own time for analysis. Maybe that’s what they do when they’re not a researcher or a slave.
One thing I’m really excited about is having them all do their own data analysis. When I’ve done teams in the past, usually the most proficient mathematica person does all that work.
Big questions
Ok, how is this SBG? In my previous post I had some suggestions, but I’m not sure what to do yet. I think I’m leaning towards task/content based standards like “I can measure the complex refractive index of silver.” But then I’ll need to add in “I can propagate errors” as well (that’ll be assessed for every lab).
I’ve built in some lab re-assess days, and I’ll think I’ll have them apply for the slots available in those.
I’m also thinking that one of the standards will be “I can write up a formal lab report.” Maybe they’ll only have to pick one lab to do that, the rest can be results based, but not necessarily formalized. I know that the last time I taught this course, the formality of the weekly lab write-ups really piled up for them.
Ok, that’s my thoughts for now. I wanted to get them down before the weekend started. I’ll keep thinking about this and I’ll read you’re comments over the weekend. I imagine I’ll make my final decisions on Wednesday (that’s the first day of lab, the first day of lecturing is the next day). Thanks for helping!
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Maybe I’m missing something, but is there a reason they couldn’t collect data together and then still be required to analyze it separately, regardless of what other decisions you make about lab structure?
I like the idea of task/content based standards that get assessed through them doing the labs. I also think not having a formal lab report every week is probably a good thing. When they aren’t writing formal reports, you could have them just analyze the data and produce graphs with captions that show what’s going on, leaving the rest of the formal writing out. If the captions are short paragraphs in which the students explain the meaning/significance of their graphs, I think that would probably be enough for you to tell whether or not the student understands what’s going on, which is all you really need to assess the task/content standards, right?
Hi Becca,
I’ve found I’m not great at making sure they really do their own data analysis. It seems one person figures out the cool mathematica approach and then emails it to everyone else. But, in principle, I think that’s something I should keep in mind.
As for the lack of formal reports, I like your point about long captions, or, more probably in my situation, screencasts from students walking me through the lab assessment.
Andy one thing I did to start off my Advanced Lab is to have each team do a slightly different measurement and then they shared their data for different analyses. We were using GMTs and had task like half-life measurement, shielding, finding the Geiger plateau and the dead time measurement. Groups then used a couple of different data sets for their analyses and then each group prepared a whiteboard and presented it to the rest of the groups. This idea is loosely based on some of the stuff that Mylene was doing last term.
If you can come up with a few experimental tasks for each type of equipment, I really liked how this format worked. Perhaps there are some ideas in here that you can make use of.
Thanks, Joss. A recent blog post by a rookie physics teacher pointed out to me how often I try to reinvent the wheel. I’ve got to make use of the great ideas that you and Mylène and others have for me. I think carefully assessing how they can all deal with the same data set is a great idea. In fact, our first lab is the speed-of-light lab with the spinning mirror (I only have one set up for that) and so it’s a great opportunity.
Thinking of the standards that get reassessed (propagating errors, etc.). You could use a weighted average, but another suggestion is to simply consider “propagating errors” to be part of “analyzing the complex refractive index.” In my mind, the only reason to record the standards separately is if it’s too hard to tell which one of them went wrong when they’re combined. In this case, would you be able to tell from their data whether an incorrect conclusion was due to bad lab technique or bad data propagation? If you can easily distinguish them, there isn’t necessarily any reason to have a separate standard. A submission where error propagation is done poorly is simply considered incomplete. (Or rejected. Or whatever you will do if the standard is not demonstrated.)
What if I can easily see what caused the mistake but they can’t? Would that be a reason to split the standard? I guess either way I would give them appropriate feedback, and I suppose, in the end, that’s all that matters.
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