Tag Archives: Labs

[SBG] Grading Chemistry Labs

I haven’t liked how I’ve been grading Chemistry labs for the past 2 years. I used to break labs down into categories with different weights of points adding up to 30.  The categories looked something like this.

And since I didn’t overwhelm my students enough in the first two years, I decided to give them wall of text to never read through & (never) understand how they were supposed to write labs.

All of this I made from scratch because I had never been trained as a science teacher (my teaching license is still only in mathematics), but enough of the cheap excuses.  As my 10 grade chemistry teacher used to tell us

Excuses are tools of incompetence,

they build monuments of nothingness,

and those that engage in their usages

are seldom capable of anything but excuses!

Yup, I still remember this, even down to her use of the word “usages” instead of “uses”. Unfortunately we did very few labs that year, so most of what I learned about writing down labs came from my college professors, who always had a particular pet peeve, such as “everything must be written in pen instead of pencil” and would count off disproportionately for doing their pet peeve.  So what I learned was a bunch of random rules that had little do with helping students actually become better writers or scientists.

Fortunately, with my switch over to SBG this year, I can revamp my grading accordingly and use SBG on labs, so I can start looking for the right things in lab books.  Plus, I’ve got a little better idea of what I’m looking for, having taught Chemistry for two years now.

So I’ve got the following rubric, where each of these 5 standards are graded separately.

Students tape this to the inside of their lab book so they can easily reference it.  This is much cleaner and more to-the-point than my previous attempt at explanation.  Hopefully this will help students to become better at writing these labs.

I just finished grading the first round, and I felt like I was looking more comprehensively at the lab as a whole by doing this.  When grading, I use the following document.

I cut these up and one of them to the student’s lab.  The nice thing is that if any other standards from the course were included in the lab, I can just write that down on the lab book right under where I staple this, so they can see it.  I still have to explain SBG to the poor students, so I’m still debating when to do that: now as they receive their first grades in the class, or in a week when they’ve got their first repeat of a standard?

It took me a while to grade these (about 2 hours for 45 or so students), but then again, if I’m being honest with myself and my students, it should always take me a long time to grade lab books because they took a long time to write them up.  I think that breaking down the lab book into standards helps me to focus on one standard at a time and focus on each part of the lab appropriately.

I’ve already hit a dilemma where Significant Figures is its own stand-alone standard, and part of a standard within lab books.  Perhaps in the future I’ll combine those somehow, though I’m not sure how at the moment.

In addition to writing a number for each standard, I’ll still continue to leave comments throughout the lab, though these are also made easier by the little sheet.  Instead of asking “where’s your Error Analysis?”, the student actually sees their score on that element, and realize that they forgot it.

Here’s an example of a graded lab book page.

LabBookExample

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