What's That Green Stuff?

“What’s that green stuff?” Seniors complete their independent Biology experiments.


January 7, 2019
Karen Mattick, WSA IB Biology teacher

Initial phytoplankton culture for a senior’s Biology project - Karen Mattick photoOf all the experiments running in the Life Science classroom during the seniors’ biology experiments, the bubbling beakers filled with something vividly green received the most attention. That green stuff is Nannochloropsis phytoplankton. The experiment investigated the effects of salinity on the photosynthesis rate of these microscopic plants. The student made use of a dissolved oxygen sensor from our growing collection of electronic sensors in order to measure changing photosynthesis rates.

This experiment is one example of the fifteen student-designed investigations created this year as part of the International Baccalaureate (IB) Diploma Program’s Internal Assessments. Each discipline in the IB program has some form of assessment in which students demonstrate the knowledge, skills, and analysis unique to the subject area. In Biology, students research topics of their choice in scholarly journals and then design their own investigations. They run their experiments for two to three weeks, sometimes having to revise their plans when things do not go as expected. Their formal lab papers are graded by their Biology teacher and then a random sample are sent to IB Examiners who verify that the teacher’s grades reflect IB’s criteria.

Other senior projects includes investigations of the effects of de-icing salts and ocean spray on plant growth. Two students worked in the Chemistry lab testing foods for concentrations of different macromolecules. Another senior completed an analysis of local bird populations using Cornell University’s eBird database. Two students worked outside the classroom, one investigating the effects of different levels of shade on two species of herbaceous plants and the other exploring the habitat preferences of liverworts and moss.

These Biology projects and all the other Internal Assessments require that IB students synthesize what they have learned and think in a sophisticated way about course content. For example, in addition to designing and carrying out their investigations, the seniors must select the appropriate statistical tests to analyze their data. They choose the best graph styles for conveying what happened in their experiments. In addition, they connect what happened in their experiments to the larger scientific context they researched in the professional literature.

If you want to see those vivid green phytoplankton, stop by the Life Science room where a culture lives on even though the experiment has ended.