Population Growth Curves with Bubbles

This was another mini lab from the collection of labs from Dr. Close that I blogged about here. In this lab students were recreating the 3 different population growth curves by caring or not caring for a population of bubbles.

For the growth curve of k selected species who care for their young to maturity, students blow a bubble and do everything in their power to not let the bubble pop. This included blowing on the bubble and fanning it away from obstacles. This section certainly takes the longest because the bubbles last the longest. I started getting nervous that we wouldn't finish within out 80 minute time frame while students worked on this population, but fortunately, the other two population types go more quickly. Personally, I found this the most hysterical section of the lab, and I think students would agree. (Although none of my pictures quite captured how funny they looked chasing their bubbles around.)

In the next population, students blew a bubble, but could not help it along. This was a hard transition after protecting the first 50 bubbles so carefully.

In the final population, not only could students not help the bubbles, but for them to survive past birth, the bubble had to cross over a meter stick that was one meter in front of the bubble blower. These results mimic the r selected species, often where parents lay many eggs with no parental involvement past that.

After data was collected, students graphed their data on semi-log paper to see how well it matched to the graphs in their textbook.  I reformatted the lab into this document. For the semi log paper, I like the paper from here and choose the 2 decades paper.

This was a great lab to get students outside and moving around a lot. The lab also gave them a real experience to relate back to the graph they needed to understand.