Using the pH Scale and Carbonic Acid Formation to Understand the Effect of Ocean Acidification on Organisms with Calcium Carbonate Shells.
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This page first made public: Mar 31, 2014
In this lab activity, students work with the pH scale and the reaction of carbon dioxide with water to understand how anthropogenic carbon dioxide causes ocean acidification. Next students use weight loss from shell pieces in solutions of different pH values to examine the effect of acidification on calcite dissolution. Then students graph atmospheric and oceanic carbon dioxide levels over time to see how the ocean is responding to increased levels of carbon dioxide in the atmosphere. Finally, students make predictions regarding how oceans might be affected by anthropogenic carbon dioxide.
Context for Use
Description and Teaching Materials
This activity is divided into five parts. Parts 1-3 are done in the first week, and parts 4 and 5 are done in the second week. In Part 1, students answer basic questions about the pH scale using a pH scale that includes the pH values of pure water, seawater and various household solutions. In Part 2, students blow into a solution of distilled water and bromothymol blue to observe the effect of adding carbon dioxide to water on its pH. In Part 3, students observe the effect of vinegar on a piece of chalk and then weigh shell pieces, place them in solutions at various pH values, and measure weight changes after one week in the solutions. In Part 4 students graph atmospheric and oceanic carbon dioxide concentrations over time to determine how the ocean is responding to increased atmospheric carbon dioxide levels. In Part 5, students read an online article and make predictions about the effects of anthropogenic carbon dioxide on the oceans.
- Ocean Acidification (Microsoft Word 70kB Mar27 14)