Thursday, October 28, 2004

Winogradsky Columns

Wednesday, I discovered a possible limit to my tolerance of chaos-in-the-name-of-science: the Winogradsky column. To make a Winogradsky column, you mix pond mud, water, a raw egg, and shredded newspaper and pour them into a cylinder (spring water bottles, for example). Then you cap them, put them near a light, and observe over time as bacteria of different kinds and colors grow at different levels within the bottle. Easy enough, right?

I did not think through the process of getting the mud into the bottles, so I found myself feeling that things were perhaps just slightly out of control as my students proceeded to pour mud all over the desks in my classroom. Looking back, I must admit they tried. Funnels would be an obvious improvement for the future.

Yesterday and today, I got them started on their observations. We put one bottle in the dark, one in natural classroom light, and one in front of a bright light. Each day for the next two weeks, they are to draw and describe what they see in the bottles. So far, white clumps have formed within the bright and natural light bottles; we'll see what develops over the next few weeks! In theory, we'll be able to see layers of aerobic and anaerobic bacteria, with more photosynthetic bacteria in the light conditions. I'll keep you up-to-date.

I will say this. I left school on Tuesday feeling a little disillusioned by the Winogradsky experiment; it seemed like too much work and mess to be worth it. But I am emphasizing careful observation with my students, and giving them plenty of time to make detailed drawings and take descriptive notes, and they are doing an excellent job. Their drawings are much, much better than any they've done before. So this may turn out to be a good way to teach observation skills.


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