Tuesday, November 02, 2010
I was going to try and post this Sunday, but I ran out of time. I'm having one of my classes measure some tombstones for their lab activity. They'll collect data on the width of marble tombstones a measurement at the top, and one at the bottom. Then they'll plot the change in thickness versus the date on the grave.
This is a pretty easy and fun activity - it's got some good pedagogy, too. It forces the students to actively participate in the learning activity, students have an opportunity to collect, graph, and analyze data. It also has connections with interesting and current research in the weathering rates of various materials.
I'm having the students use rulers, rather than calipers - I feel like the risk of damaging the grave markers is too high with students using a couple dozen steel calipers. I may try to get some inexpensive plastic-jawed calipers in the future. As a test, I gathered a few measurements from a nearby cemetery to see if students would be able to get usable data. Most of the thickness variation was more than 1mm, so they should get precise enough measurements to see a general trend. At the end of the week, we'll collate all the measurements and then the students will analyze and plot the class data - turning in a lab report next week.
My quick data collection produced a weathering rate estimate of about 0.03 mm/yr, which is fairly slow, compared to some other locations. But my data set is pretty small - and I suspect a few of these gravestones were "resurfaced" in some way.
A few links:
I based my lab activity off of the SERC's weathering rate activity write up:
GSA is sponsoring a research/outreach program about gravestone weathering, too - some cool and time-appropriate citizen science: