In this lab activity, students examine phytoplankton and picophytoplankton under a microscope and learn how to use a stage micrometer to measure microscopic specimens. Resources needed include a microscope, slides, coverslips, a stage micrometer, and a phytoplankton/picophytoplankton sample obtained from a biological supply company. The lesson is supported by science content found in the journal, Rising Tides, focusing on current oceanography research conducted by scientists at NASA, NOAA, NASA, and universities. Rising Tides contains articles, classroom activities, readings, teacher/student questions, imagery and more designed for the biology/environmental/earth science classroom.