Lesson Plan: Teaching the pH Scale, and Acids and Bases through Climate-related Examples

As a high school Chemistry teacher, you can use this set of computer-based tools to help yourself in teaching the pH scale, acids and bases, acidification, and environmental chemistry.

This lesson plan allows students to understand the pH scale and acidification by analyzing the effect of atmospheric carbon dioxide on ocean chemistry. The activity will also explore the potential effects of climate change on ocean acidification, and the possible impacts of ocean acidification on marine organisms. Thus, the use of this lesson plan allows you to integrate the teaching of a climate science topic with a core topic in Chemistry.



Use this lesson plan to help your students find answers to:

  • What is the pH value of ocean water? Is it alkaline or acidic? 
  • What are the main chemical reactions in ocean acidification? 
  • How could an increase in fossil fuel usage change the pH value of ocean water? 
  • If ocean water became more acidic, how might it affect oyster and sea urchin populations? 
  • What are the possible impacts of climate change on ocean chemistry?

About Lesson Plan

Grade Level High School
Discipline Chemistry
Topic(s) in Discipline • pH Scale, Acids and Bases, Acidification
• Ocean Carbonate Chemistry, Seawater Chemistry,
• Aragonite Saturation State,
• Ocean acidification
Climate Topic Climate and the Hydrosphere
Location Global, USA
Languages English (Visualization tool is available in English, French, German, Portuguese, and Spanish)
Access Online (some material can be downloaded for offline use)
Approximate Time Required 120-150 min


Visualization (~45 min) A visualization that introduces the topics of pH scale, pH of different liquids, ocean acidification, and possible impacts of ocean acidification on marine life.
Video (~6 min) A video that introduces the topic of ocean acidification and examples of the effects of higher ocean acidity on marine life and on the seafood industry.
Classroom/ Laboratory activity (60 – 90 min) A classroom/laboratory activity to explore and analyze the relationship between the growth of oyster larvae and the chemistry of ocean water (aragonite saturation state) by using actual data from the Whiskey Creek Hatchery in Oregon, USA.

Here is a step-by-step guide to using this lesson plan in the classroom/laboratory. We have suggested these steps as a possible plan of action. You may customize the lesson plan according to your preferences and requirements.


1. Introduce the topic through an interactive visualization
  • • Introduce the topic of acids and bases.
  • • Proceed with your existing lesson plan to explain the pH scale.
  • • Discuss the pH values of various common compounds.
  • • Give a few examples of chemical reactions that generate acids and bases.
  • • Next, use “part 1” of the visualization, “Our Acidifying Ocean,” from the Inquiry to Student Environmental Action (I2SEA) project for an interactive learning session. The tool will help you introduce the topics of pH scale, pH of different liquids, ocean acidification, and possible impacts of ocean acidification on marine life
  • • The tool can be accessed at: http://i2sea.stanford.edu/AcidOcean/AcidOcean.htm
  • • It is available in English, French, German, Portuguese and Spanish.
  • Note: This tool requires a Flash player, and therefore, may not play in some browsers. The visualization tool works well in Firefox and MS Edge.
2. Play a short video
  • • Then play this short video (approx. 6 min), “Ocean Acidification”, to explain how carbon dioxide (CO2) affects the pH of the ocean and how an increase in ocean acidification might adversely impact marine animals.
  • •  The video “Ocean Acidification”, provided by the National Science Foundation and NBC Learn (available on Science360 News Service), is available at https://news.science360.gov/archives/20110520
3. Conduct a classroom/laboratory activity Now, explore this topic in an engaging manner through a classroom/laboratory activity, “Ocean Acidification and Oysters Lab”, created by Hilary Palevsky, UW Oceanography.
This activity will help your students explore how a change in ocean chemistry can affect the growth of marine organisms, specifically, oyster larvae. Students will use actual data from the Whiskey Creek Hatchery in Oregon, USA, to plot graphs in MS Excel, and perform data analysis and interpretation.

“Ocean Acidification Killing Oysters by Inhibiting Shell Formation”

Mapped Sustainable Development Goal(s), apart from 4 and 13

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