Teachers may pose a series of ocean-related questions, such as, "What would happen if there was no limit to the number of swordfish that fishermen were allowed to catch?" or "How would a worldwide decrease in water temperature affect ocean populations?" or allow students to generate their own questions as the teacher reads grade-appropriate scientific literature about oceans. Encourage students to conduct research in the library or at home to see if an answer can be found.
If students are unable to find an answer to the ocean questions posed in class, or if they want to test the information they found to see if it is really true, teachers should assist students in formulating a plan to determine an answer. Third graders often need help wording a hypothesis correctly and teachers should discuss in detail the criteria for formulating a hypothesis and designing an experiment to test it. For example, if a student is curious about why starfish populations are higher than ever before in recorded history, help students generate possible reasons this could happen and choose the one they believe is most likely, such as the increase is due to a decline in the population of their natural predators. Ask students how they could find out if this idea makes sense.
After proposing a possible answer to the question formulated at the beginning of the scientific method, students must gather information that will confirm or dispute their proposed explanation. Students in coastal regions may be able to gather ocean samples to observe, while other third graders will need to rely heavily on research. Guide students in finding reliable sources, such as marine institutes and the National Oceanic and Atmospheric Administration. For example, in an experiment related to marine life population levels, students should determine the organism's food chain and gather population records to determine if there is a correlation between the populations at each level in the chain.
Third grade students develop critical analysis skills by learning to interpret data gathered in an experiment and explain its significance in the context of a question and theory. Teachers should assist students in finding the appropriate means of displaying the information gathered, such as a chart or graph, and assign students to prepare a short presentation covering the steps of the scientific method and the way they were applied to the specific ocean investigation conducted, with a final solution proposed to the initial question asked.