I’ve been working with my three science classes on the Problem-based lesson I created this summer at the Eighth Floor. It’s gone well, and students have progressed in their understanding of the Scientific Method as hoped. We’re more than halfway through this nearly three-week unit, and Friday’s classes performed the lab experiments they’d designed. I hadn’t initially planned to do labs until Monday, but by Thursday it was clear the groups were ready.
On Friday we were late starting first hour because of a faculty meeting that ran a little long. But students burst into the classroom asking, “Are we doing labs today?” I said I wasn’t sure we’d have time because of the late start, the word root quiz we do every Friday, and the daily discussion board question they were required to complete. “Oh, please. We’ll hurry.” They rushed other students who were still getting settled. “Hurry up!” they admonished their classmates. “We’re going to do labs!”
What science teacher could resist such eagerness? I know I can’t. I’d prepared the classroom’s lab table with beakers, test tubes, triple beam balance, stirring rods, pipets, acid, assorted antacids for testing and other lab equipment they’d requested. The table was so full, in fact, that as soon as students turned in their quizzes, they grabbed supplies off the lab table and brought them to their work tables where there was more room. I didn’t realize it yet, but this was the beginning of a sharp detour.
Before I could finish helping one group into their lab coats and goggles, the other one had two types of antacid powder ground in the mortar (which was which??), acid measured into test tubes, and a pad of pH paper was already lost. It was all I could do in the next thirty minutes to keep up with bringing paper towels to sop up overflowing Alka Seltzer, reminding students to record observations and data, and repeating, “What’s your procedure say?” when they asked what they should do next. When the acid-antacid mixture from one student’s shaken test tube splashed out onto the books and laptop on the table, my head nearly exploded.
There will be plenty to reconstruct on Monday when we attempt to reflect on the labs and analyze what the results tell us. I was disappointed on Friday that in their enthusiasm, students had hydrochloric acid and antacid powders sloshed all over the tables. Their technique was terrible! And it seemed they missed the point of the lab entirely. But the truth is that real scientists do a lot of sloppy work on the way to profound discoveries. I should know; I’ve done some pretty sloppy science in my day. I hope to take advantage of this situation to drive that point home.
Students too often feel they’re not allowed to make mistakes in class. They don’t want to look foolish by being “wrong.” But some lab experiments cry out for do-overs, and I think this one qualifies. It’s a detour from my unit plan, but a great opportunity to stress neatness and precision in mixing and measuring chemicals.
I’m insisting they work at the lab tables next time; we’ve had enough chemical spills to last the year. The up side? Now I won’t have to explain (again) why eating is forbidden in my classroom.