Wednesday, February 11, 2009

bacterial colonies

10.21.08. It's always good to measure something in more than one way. A second way to estimate the number of bacteria in a colony is to use areas. We brought in petri dishes on which bacteria had grown for 8 hours (courtesy of Laura Wingler at Columbia), forming circular colonies. By measuring the area of a bacterial colony, and dividing by the area of a single bacterium, students obtained a second estimate of the population size of an 8-hour-old colony of bacteria.