Abstract
Over the millennia, phytoplankton have evolved adaptations to reduce sinking rates and increase the amount of time they are able to stay in the photic zone; one such adaptation is increasing form resistance with larger surface areas. Spines, flattened body shape, forming chains, and so forth can increase surface area and slow sinking rates. While there are many plankton sinking rate activities accessible on the web, this middle and high school level laboratory activity is modified to make data collection easier and more reliable, and adds a dash of a STEM engineering challenge. Students first test equal-sized spherical clay ‘plankton’ with differing numbers of spines to see how body projections affect sinking rate, then they create different shaped plankton in a challenge to be the slowest to sink. The use of corn syrup as the ‘ocean’ makes a crucial difference from the classic plankton race activity – it allows the plankton to sink slowly enough that students can get good data, and it represents the ocean’s viscosity as experienced by plankton. This engaging 5 E’s marine biology and oceanography activity is presented as a STEM challenge – can your students create the slowest sinking plankton? Students practice doing science and utilize experimental design, they use math to test biological predictions, they graph and analyze data, and then use the data as evidence as they defend their conclusions utilizing the claim-evidence-reasoning format.