Teaching Rates and Cycles in Oceanography
Leah May Ver, Earth and Ocean Sciences, University of British Columbia
I teach courses on Introductory Oceanography, Intro Geology, and Natural Hazards/Disasters to mostly non-science major students at the University of British Columbia. More than half of my classes are online (distance education). Teaching at a distance, especially science and to non-science students presents a unique and quite challenging situation.
We cover the concept of deep geological time when we discuss mass extinctions in my Natural Hazards/Disasters class and in learning about plate tectonics, the rock cycle, etc in my Intro Geology class. Since I expect a lot of participants in this workshop to focus on these issues, I've decided to share my experiences about teaching about time/space scales and rates of recycling in my Introductory Oceanography class.
We spend quite a bit of time discussing these concepts when we study the evolution of the oceans, the interaction of the geo/bio/chem processes within the ocean, and much later in the term, the carbon cycle. Although students can easily grasp the concepts of process rates, of material and energy recycling, and the time/space scales that each operate over, they struggle when considering the interaction between these cycles or when having to compare numbers that differ over large scales of magnitude.
For example, we talk about how the "short-term" increase in atmospheric CO2 affects/interacts with the longer-term scale of ocean mixing or carbon export to the sediments. To help students understand these concepts, I use analogies with banking/money, bicycle gears, factory processes/assembly lines and reservoirs/bathtubs. Success in these strategies highly depends on the student's experience. In the bicycle gear analogy, we talk about the difference in the rate that legs pedal compared to the rate at which the bicycle wheels turn. The students who've actually ridden bikes like this analogy as they've actually experienced the effect of changing gears. The banking analogy, however, is not always helpful as many students don't seem to have had much experience in this type of cycling!
As expected, students do quite well when assessed on Bloom's cognitive level 1 (knowledge) but struggle with the 2nd (comprehension) and 3rd levels (application).