Implement this lesson:
After going through NOAA Ocean & Coastal Acidification Unit
Learning objective:
To understand the harm of ocean acidification on shellfish by allowing acids of different strength to degrade sea shells.
Next Generation Science Standards (NGSS)
MS-ESS3-4
Construct an argument supported by evidence for how increases in human population and per-capita consumption of natural resources impact Earth’s systems.
Science and Engineering Practices
Engaging in Argument from Evidence Engaging in an argument from evidence in 6-8 builds on K-5 experiences and progresses to constructing a convincing a r g u m e n t that supports or refutes claims for either explanations or solutions about the natural and designed world(s). Construct an oral and written a r g u m e n t supported by empirical evidence and scientific reasoning to support or refute an explanation or a model for phenomenon or a solution to a problem.
Disciplinary Core Ideas
ESS3.C: Human Impacts on Earth Systems Typically, as h u m a n populations and per-capita consumption of natural resources increase, so d o the negative impacts on Earth unless the activities and technologies involved are engineered otherwise.
Crosscutting Concepts
Cause and Effect Cause and effect relationships may be used to predict phenomena in natural or designed systems.
Texas Essential Knowledge and Skills (TEKS)
4.7(C) identify and classify Earth’s renewable resources, including air, plants, water, and animals; and nonrenewable resources, including coal, oil, and natural gas; and the importance of conservation
4.8(A) measure, record, and predict changes in weather
4.8(B) describe and illustrate the continuous movement of water above and on the surface of Earth through the water cycle and explain the role of the Sun as a major source of energy in this process
5.5(C) identify changes that can occur in the physical properties of the ingredients of solutions such as dissolving salt in water or adding lemon juice to water
5.9(A) observe the way organisms live and survive in their ecosystem by interacting with the living and nonliving components
5.9(B) describe the flow of energy within a food web, including the roles of the Sun, producers, consumers, and decomposers
5.9(C) predict the effects of changes in ecosystems caused by living organisms, including humans, such as the overpopulation of grazers or the building of highways
6.5(A) know that an element is a pure substance represented by a chemical symbol and that a compound is a pure substance represented by a chemical formula
6.5(B) recognize that a limited number of the many known elements comprise the largest portion of solid Earth, living matter, oceans, and the atmosphere
6.5(C) identify the formation of a new substance by using the evidence of a possible chemical change such as production of a gas, change in temperature, production of a precipitate, or color change
6.7(A) research and discuss the advantages and disadvantages of using coal, oil, natural gas, nuclear power, biomass, wind, hydropower, geothermal, and solar resources
Overview
Approximately 30% of CO2 released into the atmosphere is absorbed by the ocean. Therefore, as atmospheric CO2 levels increase so do ocean levels. As the ocean absorbs CO2 a series of chemical reactions happen resulting in increased levels of hydrogen ions. This means the ocean becomes more acidic. The resulting acidification means a decrease in carbonate ions crucial for shell building animals. It becomes increasingly difficult for animals such as coral, oysters, and clams to create and maintain their shells. Chicken eggshells are made of the same material (calcium carbonate) as seashells.
Materials
- empty pieces of eggshells
- vinegar, soda, ammonia, freshwater, bleach
- pH testing kit
- petri dishes or other small dishes
- hand lens or microscope
- eye dropper or pipette
Advanced Prep:
- Either a teacher or student determines the pH of each liquid. Record on board or data sheet
- Place each liquid in a small beaker or dixie cup
- Review effects of acids and bases on oysters shells using a microscope https://docs.google.com/presentation/d/19ImfY80agilDZtVto-UgQ-fL4qX-0JuadaqW6XQXHsk/edit?usp=sharing
Procedure:
- Look at the eggshell under microscope or hand lens
- Place a piece of eggshell on a small petri dish and slowly drop vinegar onto it. Repeat this experiment with each liquid on a different eggshell
- Look at each eggshell under the microscope/hand lens again
- If possible leave your eggshell in the different liquids overnight or longer. After the determined time, look at it under the microscope.
| Picture of Eggshell | Sentence describing what you saw | |
| Eggshell prior to treatment | ||
| Vinegar (pH #) | ||
| Bleach (pH #) | ||
| Ammonia (pH#) | ||
| Water (pH#) |
Questions to Ask:
Pre-experiment
- Predict what will happen to the eggshell because of each liquid?
- What will happen if we leave the eggshell in longer?
- How is a seashell similar to an eggshell?
Post Experiment
- Which liquid had the greatest impact on the shell?
- How did pH affect the liquid’s impact on the shell?
- How would shelled animals in the ocean be impacted by this?
Extensions:
- Watch video: https://www.youtube.com/watch?v=ZimEBFw1Q7c
- Complete a pH chart with a picture of the eggshell at pH 7, 6, 5, etc.
- Repeat the experiment again with seashells
Evaluation:
Have students create a digital movie (iMovie, microsoft movie maker, screencastify) explaining the effect of OA on shelled marine creatures.
Want a different explanation and lesson plan? Check out this redesigned lesson from one of our grant teachers: https://docs.google.com/document/d/18A6evsxllwnvG1Q1wyGKE0hp7lKTeuk0vQNfebYbezk/edit?usp=sharing
