This curriculum of five lessons teaches students acid-base chemistry through ocean acidification, an environmental issue that is threatening marine ecosystems. Each lesson includes a combination of teacher lectures and demonstrations and student activities. Students will first learn about pH and buffering capacity of solutions such as the oceans. Then they will investigate the influence of humans and marine animals and plants on the acidity of the oceans. The curriculum ends by having students research the effect of ocean acidification on marine life; creating an information brochure about ocean acidification serves as the final project of the curriculum.

  • Students will identify acids and bases. They will be able to relate this classification with a pH number and hydrogen ion concentration.
  • Students will learn that seawater is slightly basic.
  • Students will identify different sources of sand found on beaches.
  • Students will explore buffering of seawater and model CO2 chemistry that allows buffering of blood and seawater pH.
  • Students will learn about the relationship between atmospheric CO2 and seawater pH.
  • Students will interpret graphs.
  • Students will develop research questions, hypotheses, and experiments to test them.
  • Students will learn how to make graphs and scientific posters on the computer.
  • Students will learn that biological processes also influence seawater pH. These processes can help combat ocean acidification or make it more extreme.
  • Students will develop ways to mediate the effects of ocean acidification on marine life.
  • Seawater is a neutral solution since it is water.
  • High pH value means a solution is more acidic.
  • More hydrogen ions lead to a bigger pH number.
  • Sand only comes from weathered rocks.
  • Solutions will change pH when a strong acid or base is added to it.
  • Buffering of seawater pH is controlled by salts.
  • When we hold our breaths, we feel the urge to breathe again because we need more oxygen.
  • Carbon dioxide stays in the air and is disconnected from seawater.
  • Seawater is becoming an acid.
  • Marine organisms breathe seawater.
  • Photosynthesis doesn’t occur in the oceans.
  • Biology does not affect seawater chemistry.
  • Ocean acidification is not a problem or doesn’t matter.
  • All marine organisms will have the same response to ocean acidification.
  • This unit is composed of five lessons which should be taught in order as the concepts build on one another. Each lesson includes a PowerPoint Presentation, which lists the lecture content and descriptions of lesson activities, and accompanying worksheets where necessary. Each lesson includes a combination of lecture, demonstrations, and independent and group student activities. Materials needed for each activity is listed in the PowerPoint Presentation.
  • This lesson relates the concepts of pH, hydrogen ion concentration, and classification of solutions as acidic, neutral, or basic.
  • Students will explore how seawater and blood regulate pH through buffering by CO2 reactions.
  • Students will review the carbon cycle by identifying sources and sinks of carbon and then learn how atmospheric carbon dioxide changes seawater pH.
  • This lesson teaches students that biological processes such as respiration and photosynthesis may also influence seawater pH.
  • This lesson completes the unit by having students explore the response of marine organisms and ecosystems to ocean acidification.
  • This unit was designed for a high school chemistry class but can also be taught in middle life science and high school environmental science. The students should have prior knowledge of the carbon cycle before beginning this unit. The lessons should be taught in order as the concepts build on one another.
  • Various methods of assessing students are given in the notes of the PowerPoint Presentations. For Lesson 5, a grading rubric is suggested for the final project (information brochure).
  • Many activities within this curriculum include measurements of pH. While pH meters can be used for any/all of the activities, indicator dyes are much cheaper and easier for students to handle. The most applicable dye for each activity is listed in the lessons and a handout provides more information (including color scales) about the indicator dyes used throughout the curriculum.
  • MS-PS1-1: Develop models to describe atomic composition of simple molecules and extended structures.
  • MS-PS1-2: Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
  • MS-PS1-4: Develop a model that predicts and describes changes in particle motion, temperature, and state of a pure substance when thermal energy is added or removed.
  • MS-PS1-5: Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved.
  • MS-LS1-6: Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.
  • MS-LS1-8: Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate behavior.
  • MS-LS2-3: Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.
  • MS-ESS2-1: Develop a model to describe the cycling of Earth’s materials and the flow of energy that drives this process.
  • MS-ESS3-3: Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.
  • HS-PS1-2: Construct and revise an explanation for the outcome of a simple chemical reaction.
  • HS-PS1-3: Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.
  • HS-PS1-6: Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.
  • HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.
  • HS-LS2-5: Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.
  • HS-ESS2-5: Plan and conduct an investigation of the properties of water and its effects on Earth materials and surface processes.
  • HS-ESS2-6: Develop a quantitative model to describe the cycling of carbon among the hydrosphere, atmosphere, geosphere, and biosphere.

Clown Fish (Amphiprioninae)

Trends in seawater carbon dioxide concentration and seawater pH

Ocean Acidification Balloon Lab
Lesson Specifics
  • Grade Level: High school chemistry class or middle school life science and high school environmental science

Scripps Pier

R/V Melville
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