My first chemistry lab

Written 9-27:

Before I tell this story, I would like to put a plug in for a blog Morgan just started. It covers a lot of things I have not and can be found at http://morgancawdrey.blogspot.com. Specifically, check out his recounting of a funeral service we went to last Wednesday for a teacher’s two year old son, and spear fishing at night the Friday before that. (We killed a fish with a machete.)

This time, however, my entry has to do with teaching. Given that there are really no laboratory resources in my classroom, it’s difficult to do labs. I did one with my physics classes a while back but it just involved having them graph my motion as I walked in front of the class at varying speeds. It went alright, but wasn’t what I would call exciting.

My chemistry classes are studying mixtures right now. Most of my examples have involved sea water, sand, and whatever the students had for dinner last night. This weekend, however, I stumbled across the “mini-lab” entitled Paper Chromatography of Ink. Remember doing that lab back in 8th grade? Yes, *now* we’re talking about an exciting lab. You take a strip of paper, draw a line across it in black ink, then dip the end in a little water. As the water creeps up the strip of paper, it separates the ink into its component colors, showing you that the black ink is in fact a mixture of lots of colors.

I figured this would be a good, basic, first lab for my students to do, so on Saturday, I set it up in my kitchen to test it out. I cut a strip of paper, drew a line, dipped it in water, and after 45 minutes, nothing had happened. I looked back at the lab and noticed that it said to use coffee filter paper because it draws up the water better. I have no such paper, so the next four or five hours was spent trying to get this thing to work using things I do have. I know what you’re thinking, but don’t worry, I was doing my lesson plans for the week while the tests ran, so my Saturday wasn’t wasted. Seriously though, I baked some bread in this time, too, which provided for a delicious lunch. Permutations I tried included: drawing the line closer to the water, using paper from a cut apart tea bag, covering the tea bag paper with soap and drying it in the sun before marking it (I figured surface tension might be hindering the capillary action), covering normal paper with soap, and using different types of markers.

The soap trick sort of worked (you could see a tiny bit of blue pigment separating out), so I decided to go ahead and write up the lab. When I looked back at the teacher edition book, however, I noticed a little side-bar with teaching tips, one of which included having different lab groups use “different types of coffee filters, filter papers, or white paper towels.” Paper towels! I specifically remember buying those six weeks ago! I immediately went over to the cupboard, took out the towels, tore off the plastic wrapping, and prepared a strip. I dipped it into the jar, and water immediately rushed up past the ink and separated it out into an explosion of colors. Success! Now all I have to do is teach it. I hope they’ll find the result as thrilling as I did.

Written 9-30:

I did the lab today. It worked very well for the class that all knows English well... The other class understood it mostly... I think.