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STANDARDS
- HS-PS3-1: Create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.
- HS-PS3-2: Develop and use models to illustrate that energy at the macroscopic scale can be accounted for as either motions of particles or energy stored in fields.
- HS-PS3-3: Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.
- HS-ETS1-3: Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics, as well as possible social, cultural, and environmental impacts.
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REQUIRED KNOWLEDGE AND EXTENSIONS
PRIOR KNOWLEDGE
At the time of this Cornerstone, students should have completed Algebra 2 and have either completed Geometry or be currently enrolled in Geometry (10th or 11th grade) as students will be required to manipulate and solve an algebraic equation. The students will need to have familiarity and comfort with using a spreadsheet program, including building functions within a cell to link the changes in one variable to the changes in the other variables and plotting data on scatter plots (a tutorial is provided in handout form to supplement the students’ skill base.) Students will also need to understand solar and thermal energy well enough to create the energy model and knowledgeably build and refine a simple solar oven. Students should be familiar with identifying criteria and constraints of a design problem that include a variety of considerations. Students should be aware of the safety concerns of building a solar oven, such as skin burns and material combustion, before attempting to test their ovens.
PLACEMENT
BEFORE
This task would best situated in the Explore, Explain, and Elaborate sections of the 5E instructional sequence. This sequence may be placed at the beginning or the end of a broader unit on energy. Students should be engaged in the purpose for the creation of a solar cooker so that their engagement might continue throughout the cornerstone (i.e., within a discussion of renewable vs. nonrenewable resources, to assist impoverished countries, for cooking in locations in which access to energy resources is limited). Recommendations for engagement are included within the 5E lesson plan.
DURING
- Energy is a quantitative property of a system that depends on the motion and interactions of matter and radiation within that system. That there is a single quantity called energy is due to the fact that a system’s total energy is conserved, even as, within the system, energy is continually transferred from one object to another and between its various possible forms.
- At the macroscopic scale, energy manifests itself in multiple ways, such as in motion, sound, light, and thermal energy.
- These relationships are better understood at the microscopic scale, at which all of the different manifestations of energy can be modeled as either motions of particles or energy stored in fields (which mediate interactions between particles). This last concept includes radiation, a phenomenon in which energy stored in fields moves across space.
- Conservation of energy means that the total change of energy in any system is always equal to the total energy transferred into or out of the system.
- Energy cannot be created or destroyed, but it can be transported from one place to another and transferred between systems.
- Mathematical expressions, which quantify how the stored energy in a system depends on its configuration (e.g. relative positions of charged particles, compression of a spring) and how kinetic energy depends on mass and speed, allow the concept of conservation of energy to be used to predict and describe system behavior.
- The availability of energy limits what can occur in any system.
- Although energy cannot be destroyed, it can be converted to less useful forms—for example, to thermal energy in the surrounding environment.
- Criteria and constraints also include satisfying any requirements set by society, such as taking issues of risk mitigation into account, and they should be quantified to the extent possible and stated such that one can tell if a given design meets them.
- Models can be used to predict the behavior of a system, but these predictions have limited precision and reliability due to the assumptions and approximations inherent in models.
- Changes of energy and matter in a system can be described in terms of energy and matter flows into, out of, and within that system.
- Energy cannot be created or destroyed—only moves between one place and another place, between objects and/or fields, or between systems.
AFTER
After the students have completed their initial designs and modeling, it is recommended that students continue to refine their design within the elaborate portion of the instructional sequence. Details and suggestions for implementation are included with the attached instructional sequence.
Depending on the placement within the broader instructional unit (at the beginning or end), teachers may choose to discuss the second law of thermodynamics via HS-PS3-4 after the completion of this cornerstone activity.
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PLANNING
PLANNING
Depending on placement within the broader instructional unit, teachers can decide which concepts will be foreground and which will be background. Teachers who decide to use this cornerstone at the beginning of the unit may decide to build in more instructional time within the cornerstone fully developing students’ conceptual and quantitative understanding of energy and energy conversions, using the activities provided within the cornerstone as applications of this understanding.
The engineering design process should be highlighted with students throughout the cornerstone. Many of the portions of the cornerstone address specific selections of the high school engineering performance expectations (specifically, HS-ETS1-1, 3, and 4.) While the cornerstone may not fully address each of the performance expectations, teachers should monitor the progress of their students (either within the classroom or departmentally) in regards to these standards within the cornerstone. Also, although not specifically directed within the provided instructional sequence, it is recommended that teachers allow students to identify and reflect on specific elements of the engineering design process as they work through the cornerstone. Teachers may need to supplement this understanding with appropriate resources and/or instructional strategies.
INSTRUCTIONAL APPROACH
It is important to note that the placement within the broader instructional unit will determine whether the performance expectations connected to this cornerstone are completely addressed. If teachers utilize this cornerstone at the beginning of the unit, more instructional time may need to be spent within the cornerstone to properly develop the conceptual and quantitative ideas of energy and energy conversion (specifically, performance expectations HS-PS-1, 2.) Teachers may also decide to use the cornerstone at the end of unit as a more summative assessment of what students have learned. In this case, allow students to apply their skills and knowledge with less guidance throughout.
As written, the cornerstone may fully address HS-PS3-3. While the redesigning of the solar oven may be removed because of time restrictions, this may affect the addressing of HS-PS3-3. Teachers should use their best judgment when considering how much time to devote to each portion of the cornerstone.
Student knowledge and comfort using an Excel spreadsheet will vary. While tempting to provide students with a pre-made spreadsheet, there is value in developing these skills as they correspond with the work done by career scientists. The handout provided has been created as a means to combat gaps in student prior knowledge of Excel spreadsheets. Further, when the students create the spreadsheet themselves, they will be better suited to explain the meaning of the mathematical expression used in the model (leading to a fuller addressing of HS-PS3-1.) This portion of the cornerstone provides an opportunity to collaborate with technology or media specialists within the school building surrounding strategies for developing spreadsheet skills. Again, teachers should use their best judgment and class context when using each portion of the cornerstone.
BACKGROUND INFORMATION
General resources:
Safety:
Current Events:
Engineering design process:
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