Exploring the Scientific Method using Seashells Examining the Effects of ph Concept: The relationship between carrying ph of solutions and its impact on dissolving shells is explored. GPS: S3CS3c, S3CS5b, S3CS7a, S3P1a,c,d, S3L1b,c,d, S3L2a,b. S4CSa,b,c,d, S4E3, S4E4, S4L1a,b,c,d, S4L2. S5CS1a,b,c,d, S5CS3b,d, S5CS4a,c, S5P2c, S5L4b. Ocean Literacy Principals: 1, 3, 5 Duration: Day 1 60 minutes, Day 2 20 minutes, Day 3 60 minutes Focus Questions: How can using the scientific method help me to understand the effects of ocean acidification on seashells? Objectives: Students will: Participate in each step of the scientific method. Understand the important features of the process of scientific inquiry. Be able to communicate verbally, as well as through drawings or written record keeping their understandings of the scientific method. Make the connection between the rising CO2 levels in the atmosphere and its effects on shelled sea creatures. Background information: The oceans cover 70% of the earth s surface. Of all the water on earth, 97% can be found in the ocean. The ocean plays a large part in the distribution of energy around the globe. The ocean also absorbs excess CO 2 from the atmosphere. Many people do not realize that driving a car, running a computer, or heating and cooling a home requires energy. Most of these energy sources come from the use of fossil fuels and by using fossil fuels, carbon dioxide (CO 2 ) is emitted into the air and dissolves into the ocean over time changing the ph of the ocean water. The ocean acts like a storehouse for CO 2. The ocean is currently absorbing ¼ of the amount of CO 2 burned from fossil fuels (coal, oil, natural gas). Typically varying from 8.1 8.3 on the ph scale, increased carbon dioxide is causing some parts of the ocean to decrease to 7.9 8.2; thus making these habitats more acidic. People, land, and ocean plants and animals breathe in oxygen and put out carbon dioxide (CO 2 ). Ocean plants take in the carbon dioxide and give off oxygen, just like land plants. As the ocean changes from an increase in CO 2, scientists fear that animals with shells will be impacted as increased CO 2 means decreased carbonate, which is used in shell production. The animals that produce and create calcium carbonate shells like mollusks, mussels, clams and even coral, may possibly be affected by rising CO 2 levels. To answer these questions on what might happen, scientists are researching more on possible impacts from this change in ph. Vocabulary: carbon dioxide, scientific method, predict, observation, data, hypothesis, atmosphere, acidic
Materials: Tap water Measuring cup (1 per group) Saltwater (aquarium salt preferred) 24oz White vinegar Shell Observation Sheet Exploring the Scientific Method Worksheet Magnifying lenses (1 per group) 16oz plastic cups (3 cups per group) Permanent markers for labeling the cups (1 per group) 3 shells or shell fragments of varying thicknesses (1 set per group) (Example for one group: an ark shell, an oyster shell, and a surf clam). Lessons & Labs: Discuss the steps to the scientific method using the Exploring the Scientific Method Worksheet. The steps of the Scientific Method are: 1. Make an observation 2. Ask a question 3. Form a hypothesis / a prediction 4. Conduct an experiment 5. Record the data 6. Make a conclusion/discuss results Divide students groups. Distribute 3 different shells to each group. Pass out Shell Observation Sheets, Exploring the Scientific Method Worksheets, and magnifying glasses to each group. On the Shell Observation Sheet, allow the students time to draw and record the details of each shell. Observation is a very crucial part of any experiment. Explain that the students will be placing one of each shell into 3 liquids; tap water, ocean water, and vinegar. Using what they have learned about carbon and the effects of CO 2 on ocean water what do they predict or hypothesis will happen to each shell? Have them write their hypothesis statement on the worksheet. Emphasize that in science there can be many different hypothesis. Do not place the focus on being correct. We are in the process of learning. On the Exploring the Scientific Method Worksheet, allow students to complete steps 1 3. Pass out three 16 oz plastic cups to each group. Students label each of the 3 cups using a permanent marker as follows: tap water, ocean water, vinegar. Using the measuring cup ask each group to add 8 ounces of tap water to the cup labeled, tap water. Place the shell that was drawn in the first box labeled Shell 1 on the observation worksheet into the tap water. Add 8 oz of salt water to the cup marked, ocean water. Place the shell that was drawn in the middle box ( Shell 2 ) of the observation worksheet into the ocean water. Measure and add 8 ounces of vinegar to the third cup; vinegar. Place the shell that was drawn in the box marked Shell 3 on the observation worksheet into the vinegar. Place the cups somewhere where they will not be disturbed. The following day use the Shell Observation Sheet to record and draw any changes that have occurred in the shells.
For the final day, Day 3, record, draw, and allow students time to think of reasons that the shells may or may not have changed. Have the students discuss their responses and complete questions 5 & 6 on the Exploring the Scientific Method Worksheet. Explain why the shells placed in the vinegar deteriorated and the others did not. Seashells contain calcium carbonate. When CO 2 dissolves in water, it forms carbonic acid. Carbonic acid is the same substance found in carbonated drinks like Sprite, or Coke. The calcium carbonate in the shell reacts with the acid in the vinegar and causes the shell to dissolve. As a class discuss what will happen to the shellfish of the ocean if we continue to emit high levels of CO 2 into the atmosphere? (See above background information) Assessment: Allow students a few minutes to share with their group what they learned using the scientific method. Could they do things differently? Would they add or take away anything from the experiment? Finally, using the back of their student worksheets, students should write a few statements about what they learned through the experiment. Collect, comment and expand or clarify students understandings and beliefs. Resources: NASA, Global Climate Change. What is Happening in the Ocean? Retrieved July 7, 2011 from http://climate.nasa.gov/kids/bigquestions/oceanhappening/ Pictures of Georgia seashells: http://amylyne.myweb.uga.edu/gsc/seashellgahabitat.html Credit to Nancy Boyle, Peeples Elementary School in collaboration with Brian Hopkinson (UGA Marine Sciences Department) with funding from the National Science Foundation (Award #1129326) and assistance from the Center of Ocean Sciences Education Excellence SouthEast (COSEE SE). More lessons available on www.cosee se.org
Shell Observation Sheet Name Date Exploring the Scientific Method using Seashells Day 1 Observations on 3 seashells: Drawings: Shell 1 Shell 2 Shell 3 Notes: Hypothesis: The shell placed in tap water will. The shell placed in salt water will. The shell placed in vinegar will. Name Date Exploring the Scientific Method using Seashells
Day 2 Observations on 3 seashells: Drawing: Shell 1 Shell 2 Shell 3 Notes: Name Date Exploring the Scientific Method using Seashells Day 3 Observations on 3 seashells: Drawing: Shell 1 Shell 2 Shell 3
Notes: Conclusion: The shell placed in tap water. The shell placed in salt water. The shell placed in vinegar. On the back of this paper explain why you think the shells did or not change.
Exploring the Scientific Method Worksheet: Shells in a Changing Ocean 1: Make an observation. Sea shells are the hard protective coverings of sea animals known as mollusks. Mollusks that live in the ocean depend on salty ocean water to provide the minerals needed to make their shells. There are many types and sizes of sea shells. Examine and observe your three seashells. Use drawings and words to describe what you feel, smell, and see. Notice all the tiny details of how each shell is made. Record your observations in words, sentences, or by drawing. OBSERVATIONS: 2. Ask questions. As you look at the shells, how might those shells or the animals that made those shells change if their oceans were different? 3. Form a hypothesis. Make a statement on what will happen to the shells when they are placed in the different types of water: tap water, a very acidic water, and salt water. Record what you think will happen to each of the three seashells. 1. Shell in tap water will: 2. Shell in very acidic water will: 3. Shell in salt water will: 4. Conduct an experiment. Place one shell in each cup and check each day. Record observations. 5. Make a conclusion. What happened to the seashell placed in tap water? The one is salt water? And the one in the vinegar? 6.Discuss the results. Why do you think the shells did or did not change?