How do salinity and temperature affect ocean currents?
Begin a ladder of learning about ocean currents, by posing the question: “What do you know about ocean currents?” and ask students to record the date then write silently for 2-3 minutes everything that comes to mind about ocean currents. After 2-3 minutes ask for volunteers or select students to share what they know. Have students draw a line under what they just recorded and reserve the rest of the notebook page for further entries. This is the first rung of the ladder. Tell students that they will revisit the ladder as they progress through the unit and will be able to see what they’ve learned. Once again, refer back to the maps that the students made in Investigation 1 showing the locations where the rubber bath toys were found. Give students another chance to revise their original hypothesis about the movement of the toys. Remind them that they have been considering things that happen at the surface of the ocean during the last two investigations: wind, weather systems, waves, and
