Grade 7 explores cell size and nutrition

After learning the mathematical principles of surface area-to-volume ratios, students were asked to apply this knowledge to how cells carry out the vital functions of taking in nutrients and getting rid of wastes. Since the relatively low surface area-to-volume ratio of large objects presents a challenge to living things, students explored ways that biological structures can maximize surface area.

They were then asked to design their own “cell” using blocks of agar that change color when absorbing nutrients (vinegar, in this case). In the week before the Christmas Break, they competed in groups to design a cell that both maximized volume (as measured by mass) and minimized the time it took to become fully “nourished” by the vinegar.