This lesson focuses on the diffusion of gas molecules across the cuticle membrane of sea spider legs and the role body size plays in the ability of sea spiders to uptake gases. Students construct model sea spider legs of varying diameters and use them to investigate the relationship between surface area-to-volume ratios and diffusion.
This activity is designed to take place near or at the end of a unit on the ocean floor. Students should be familiar with the physical features of the ocean floor including the continental shelf, abyssal plain, seamounts and guyots, seafloor ridges and trenches, and submarine canyons. The students should have also previously learned about sonar methods for mapping the