Carbon Transfer Through Snails and Elodea

Contributor
Houghton Mifflin Harcourt Publishing Company
Type Category
Instructional Materials
Types
Simulation , Interactive Simulation , Experiment/Lab Activity
Note
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Reviews

Description

This is one of 14 Virtual Labs from McDougal Littell.  In this interactive simulation, students work to answer the guiding question, “Why might Elodea plants be important in maintaining a healthy ecosystem?”, as they set up an aquarium system containing aquatic snails and an Elodea plant.  Students are guided to review the problem, explore background information and laboratory equipment, develop a hypothesis, and then to plan and carry out an investigation to evaluate the hypothesis.  Although the experimental design is highly guided, students do have to determine what their variables are and how to set up control and experimental conditions in various test tubes.  Students may add Elodea and/or snails to the tubes, and they may incubate them under light or dark conditions.  Students may also run multiple experiments.  After conducting the experiment, students are prompted to collect, analyze, and draw conclusions from the data.  Students record their work in a virtual lab notebook, which can be printed.  Students tie these conclusions back to the original problem of setting up the aquarium.  This resource could be valuable as part of a larger unit focused on the flow of energy and cycling matter in the processes of photosynthesis and cellular respiration.

Intended Audience

Learner
Educational Level
  • Grade 12
  • Grade 11
  • Grade 10
  • Grade 9
  • High School
Language
English
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

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.

Clarification Statement: Examples of models could include simulations and mathematical models.

Assessment Boundary: Assessment does not include the specific chemical steps of photosynthesis and respiration.

This resource was not designed to build towards this performance expectation, but can be used to build towards it using the suggestions provided below.

Comments about Including the Performance Expectation
This resource could serve as one in a series of learning experiences that build up to the Performance Expectation. The virtual lab engages students in using a computer simulation to investigate the role of photosynthesis and cellular respiration in the cycling of carbon within a small, closed system. Following this experience, students might conduct informational research or additional investigations as the basis for developing a model to explain carbon cycling on the global scale. Student engagement and understanding could also be enhanced by having students work in pairs, before holding a class discussion.

Science and Engineering Practices

This resource appears to be designed to build towards this science and engineering practice, though the resource developer has not explicitly stated so.

Comments about Including the Science and Engineering Practice
Students design their investigation within a highly structured virtual environment, but they do have some important choices in designing their experiments. Students are only offered one method to collect data, i.e., observing changes in bromothymol blue solutions, but they can manipulate the number of test containers, the presence of each organism in those containers, and the light conditions under which the containers are incubated. Students are not assured of collecting sufficient data to answer the analysis and conclusion questions, but they are able to re-run their experiment, as needed. There is likely to be enough variation in students’ experimental set-ups to warrant a class discussion about experimental design and confounding factors. To support such a discussion, the teacher could ask students to record their procedures, data, and conclusions in a form (e.g., on whiteboards or in Google Slides) that can be shared with the class. Students’ ability to repeat and modify their investigations within the simulation also supports student mastery of the practice. Teachers should monitor students to ensure they are working through the simulation as a reasonable pace that allows them to process the key ideas.

This resource appears to be designed to build towards this science and engineering practice, though the resource developer has not explicitly stated so.

Comments about Including the Science and Engineering Practice
In preparation for their investigation, students are asked to form a hypothesis about the relationship between Elodea and aquatic snails. This general hypothesis then leads to directional hypotheses about how a bromothymol blue solution will be affected by the presence or absence of Elodea, snails, or the combination of the two organisms. No structure is given for the hypotheses in the virtual lab notebook. Teachers can support student thinking by providing a sentence frame, such as “If …, then …, because ….” When using this frame, teachers should emphasize that the proposed explanation following “because” is actually the hypothesis and that the if-then statement is a prediction based on that hypothesis. Students may need additional guidance in forming their hypotheses. The teacher could point out the "CO2-O2 Cycle Poster" and ask students to explain what they see in the poster, or students could do this with another student first. Then, at the end of the experiment, they could return to the poster to see if their experimental results matches what they see in the poster.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
The virtual lab directly addresses parts of the Core Idea, but additional learning experiences will be required to address it fully. In the virtual experiment, students investigate the cycling of carbon between two organisms within a simple aquatic environment that does not include geological material. The simulation also does not address exchange of carbon between the water and air. However, one of the materials provided to students in the virtual lab is a poster showing the terrestrial carbon cycle. The teacher could use that poster to launch students into a comparison and synthesis of the aquatic carbon cycle and the terrestrial carbon cycle.

Crosscutting Concepts

This resource was not designed to build towards this crosscutting concept, but can be used to build towards it using the suggestions provided below.

Comments about Including the Crosscutting Concept
To help students make the transition from a simple aquarium to the global carbon cycle, the teacher could emphasize the Crosscutting Concept of Scale, Proportion, and Quantity. Because the global carbon cycle is too complex to study directly in the classroom, it is appropriate to use a simple system like the aquarium to build student understanding of the carbon cycle. However, it is critical that students move beyond the system presented in the virtual lab to investigate the larger, more complex global system. Students might do this through additional simulations, data-based investigations, or informational research.

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
This resource could be strengthened in supporting the crosscutting concept by extending discussion about the simulation to a comparison with the global carbon cycle. Students use the simulation to investigate a small, closed system, which can then be used to understand the global carbon cycle, a much larger and more complex system. To support full student understanding of the Core Idea, the teacher will need to help students understand the ways in which the small study system is both similar to and different from the global carbon system. The teacher can do this through questioning that directly engages students in comparing the systems. For example, the teacher could ask students what each part of the model represents in the global carbon cycle.

Resource Quality

  • Alignment to the Dimensions of the NGSS: The virtual lab aligns strongly to the practices and to portions of the core ideas, but the teacher will need to work to help students bring in the crosscutting concepts in a meaningful way. Extending from this investigation to engaging students in developing a model of the global carbon cycle is one approach to incorporate the ideas of Systems and System Models. Explicit questioning that asks students to link the study system to the global carbon cycle can also bring the ideas of Scale, Proportion, and Quantity into focus for students. Alongside the focus on the crosscutting concepts, teachers will need to select additional learning experiences to build toward full mastery of the Performance Expectation. One option is to transition to an interactive simulation, such as this one from learner.org - https://www.learner.org/courses/envsci/interactives/carbon/, that allows students to explore the global carbon cycle. The combination of the small-scale virtual lab and large-scale simulation can allow students to connect the cellular process of photosynthesis and cellular respiration to the global movement of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.

  • Instructional Supports: The virtual lab engages students in investigating a relevant and authentic phenomenon that, in combination with other learning activities, can lead to mastery of the Performance Expectation. The resource does not provide guidance for differentiation and does not provide that level of customization. The most likely approach to differentiation would come in intentional formation of small groups to work through the virtual lab. Beyond that, extra support for struggling students or enrichment for advanced students will need to come through additional activities. Students can express and receive feedback on their ideas through the lab notebook, and this can be enhanced by asking students to record their methods, data, and conclusions in a more public form (e.g., Google Slides or whiteboards). The contents of the notebook can also be printed out and shared with the teacher or with classmates.

  • Monitoring Student Progress: The interactive lab notebook provides an opportunity to collect ongoing evidence of student learning. This can be enhanced through ongoing oral questioning and by asking students to record and share their methods, data, and conclusions in a more public form (e.g., Google Slides or whiteboards). Rubrics and scoring guidelines are not provided.

  • Quality of Technological Interactivity: The virtual lab provides an individualized experience based on students’ inputs, and the interactive features directly support student learning. The resource is easy to use and well designed. The experiment simulated in the resource could be carried out in the classroom, but the simulation can save time, supplement classrooms with limited lab materials, and provide a lab activity in online learning settings. One limitation is that the sequence of the simulation is rigid and does not allow for a student to go back to an earlier step.