The third lesson was designed to help students expand their understanding of ocean science and oil spill research. Students received hands-on experience working with CTD data from a NOAA research cruise. CTD refers to a package of electronic instruments that measure conductivity, temperature, and depth. Water samples can be collected at various depths using this equipment, and then it can be analyzed in a variety of ways. Students plotted the data in Excel and analyzed the plots to explain how levels of dissolved oxygen in the Gulf were affected by the oil spill. They discussed questions such as “how did dissolved oxygen vary with depth according to your graphs?” and “how were the graphs similar or different?”.