To complement the lesson that took place in the BATS data lab a hands-on activity is suggested. This soda-pop activity is one suggestion.
This simple hands-on activity will help your students explore the relationship between water temperature and the amount of carbon dioxide gas the water can hold. Have your students cool a 1-liter plastic bottle of carbonated water by placing it in an ice bath or in a refrigerator. Have them warm another bottle of carbonated water in the sun. Wait 10 minutes and then retrieve the bottles. While you are waiting, discuss how carbonated water differs from regular water, and have the students hypothesize about what will happen when they open the heated and chilled bottles. Encourage them to discuss each other's hypotheses.
When you open the bottle that has been sitting in the warm sun - phoooosssh!! Bubbles of carbon dioxide gas shoot out, spraying you with water. When you open the chilled bottle, it bubbles very little or not at all. So, the warmer a liquid, the less carbon dioxide gas it can hold. The cooler a liquid, the more gas it can hold. The same is true for the ocean. If sea water heats up, it releases carbon dioxide. If sea water cools down, it soaks up carbon dioxide.
Based on what your students have learned in this hands-on activity and the temperature-depth graphs that they created earlier in the lesson plan, have them predict and discuss during which month of the year the surface of the Sargasso Sea would soak up the most carbon dioxide gas from the atmosphere. During which month would the Sargasso Sea soak up the least?