Sunday, February 04, 2007

J.J. Thomson's Experiments--At Last, I See!

When I was an undergraduate student, I believed my chemistry and physics professors hated me. I was a biological sciences major, and had to take large lecture sections with the 200-300 pre-med and pre-vet students. They were no fun as classmates. ("Will this be on the test?" they whined; later, as an instructor, I heard a pre-med choral whine of "My daddy will sue you for giving me a C.") As a student, it was almost impossible for me to ask a question in lecture, and I never got a civil (let alone helpful) answer from a chemistry or physics professor in the three years I spent in those departments.

This was in sharp contrast to my experiences in all my other classes, from Chaucer to calculus to microbiology. Of course, I graduated loving Chaucer, and statistics, and botany....and hating chemistry. Of course, every science job I ever had after grad school was in biochemistry.

Now I'm teaching a college-level chemistry class, and having flashbacks to the seventies as I prepare lectures. I'm current on DNA, but haven't thought about electron shells, subshells, and orbitals much lately. That's how I got curious about John Thomson's nineteenth century experiments on subatomic particles and electromagnetic charges. My chemistry students were supposed to work through a little computer simulation on "how we discovered the mass of the electron," but we couldn't make it "come out right." When I did this in physics lab in 1976, with equipment old enough to have been original to Thomson's lab, we got the same non-result. I couldn't make sense of it then, but I was determined to figure it out this time. That's how I came to find these excellent links. There are some amazing student resources available now. I'm a bit jealous.

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