Ocean Acidification in a Cup

Notes from our reviewers

The CLEAN collection is hand-picked and rigorously reviewed for scientific accuracy and classroom effectiveness. Read what our review team had to say about this resource below or learn more about how CLEAN reviews teaching materials.

• Teaching Tips
  The instructions for this experiment provide alternatives for lab equipment and materials that might be unavailable, such as a substitute for the acid indicator bromothymol blue.
• About the Science
  This classroom experiment allows students to see the process of ocean acidification in action. It creates a carbon-dioxide rich atmosphere above a layer of water with a pH indicator in a cup. The carbon dioxide diffuses into the water and eventually raises the pH, which can be seen with the pH indicator. The website describes the processes of ocean acidification, the fast carbon cycle, and how these processes affect sea life. Comments from expert scientist: Scientific strengths: Easy to do, though the required supply of bromothymol blue might be difficult in some schools (thinking of schools without a chemistry shop). Suggestions: None.
• About the Pedagogy
  This is a controlled experiment that can be completed in a typical classroom laboratory setting. Students will create a model of an ocean-atmosphere interaction that shows how carbon dioxide gas diffuses into water, and compare it with a control. Before conducting the experiment, students should understand how an acid indicator works and the fact that mixing vinegar and baking soda creates CO2 gas. This classroom experiment can be done as a demonstration or a lab activity. The website provides explanations, references, and discussion questions, and teaching tips.
• Technical Details/Ease of Use
  Video provides an example of how to do the demonstration. Instructions are very comprehensive and easy to follow. This experiment can be carried out with typical classroom laboratory materials and provides useful tips for teachers.