Billion Oyster Project

Ocean Acidification and pH


New York’s Urban Ecosystem Lessons



Class Periods




Subject Areas



This lesson provides an introduction to acids and bases. It begins with looking at the acid content of several items around the house. Then, there is a discussion of pH and what it means. After that, the students complete an experiment where they look at the effect of Carbon Dioxide in water. Finally, they watch a video on ocean acidification and oysters.


  • What is pH?

  • What does Carbon Dioxide do to the pH of the ocean?

  • How does the pH of the ocean affect oysters?

Before you get started

Tips for Teachers

  • During the lab, make sure that you are the only person who handles matches.

  • For older students or advanced students, feel free to discuss that “acid” is the concentration of H+ ions. For younger students, it is probably best to talk about “more” or “less” acidity.




Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere. An estimated 30–40% of the carbon dioxide from human activity released into the atmosphere dissolves into oceans, rivers and lakes. This lesson looks at the effect on pH of creating “pollution” in water. Students will first experiment with what pH is and understand acids. Then, they will do an activity where they pollute the water with carbon dioxide and consider the dissolved oxygens.

Instruction Plan


At the front of the room, have beakers of each of the following:

  1. Tomato Juice

  2. Vinegar

  3. Lemon Juice

  4. Water

Ask students what an acid is. Ask them what they think of when they hear the word “acid.” Ask students to hypothesize about which of the following items will be the most “acidic” and rank the substances in order from most acidic to least. Write students’ hypotheses on the board. Save for later in the lesson.


Explain that pH is the scale by which acids and bases are measured. The lower the pH, the more acid there is. Explain that a pH of 7 is neutral.

Then, using your pH meter, test the pH of the substances and discuss whether or not hypotheses were correct.

Now put the following diagram up (or distribute on a worksheet):

Discuss the pH of the substances on the board. Then have students complete the “pH and Powers of 10” worksheet.


Do the ocean acidification experiment. Then, have students read the article “Are Oysters Doomed?” Discuss the effect of Carbon Dioxide emissions on Oysters.


Ocean acidification and oysters film and discussion:'s+impact+on+oysters+and+other+shellfish


CCLS - ELA Science & Technical Subjects

    • Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).

CCLS - Mathematics

    • Recognize and represent proportional relationships between quantities.

NGSS - Cross-Cutting Concepts

  • Patterns

    • Macroscopic patterns are related to the nature of microscopic and atomic-level structure.

NGSS - Disciplinary Core Ideas

  • PS1.B: Chemical Reactions

    • Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.

NGSS - Science and Engineering Practices

  • Analyzing and Interpreting Data

    • Analyze and interpret data to provide evidence for phenomena.

NYC Science Scope & Sequence - Units

  • Grade 6, Unit 2

    • Weather and Atmosphere
  • Grade 6, Unit 4

    • Interdependence
  • Grade 8, Unit 4

    • Humans and the Environment: Needs and Tradeoffs

NYS Science Standards - Key Ideas

  • LE Key Idea 7

    • Human decisions and activities have had a profound impact on the physical and living environment
  • PS Key Idea 2

    • Many of the phenomena that we observe on Earth involve interactions among components of air, water, and land.
  • PS Key Idea 3

    • Matter is made up of particles whose properties determine the observable characteristics of matter and its reactivity

NYS Science Standards - Major Understandings

    • Substances have characteristic properties. Some of these properties include color, odor, phase at room temperature, density, solubility, heat and electrical conductivity, hardness, and boiling and freezing points.
    • Substances enter the atmosphere naturally and from human activity. Some of these substances include dust from volcanic eruptions and greenhouse gases such as carbon dioxide, methane, and water vapor. These substances can affect weather, climate, and living things.
    • The environment may contain dangerous levels of substances (pollutants) that are harmful to organisms. Therefore, the good health of environments and individuals requires the monitoring of soil, air, and water, and taking steps to keep them safe.

NYS Science Standards - MST

    • Students will access, generate, process, and transfer information using appropriate technologies.
    • Students will apply the knowledge and thinking skills of mathematics, science, and technology to address real-life problems and make informed decisions.