Solar Heat Hero: Designing Portable Concave Mirror Cookers
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Solar Heat Hero: Designing Portable Concave Mirror Cookers

Grade 7Science4 days
★★★★★
5.0 (1 rating)
Students step into the role of engineers to design efficient, portable solar cookers for families in energy-poor regions by harnessing the physics of light reflection. Through rigorous experimentation with concave mirrors, learners calculate precise focal points and develop technical blueprints to maximize thermal energy concentration. The project culminates in the construction and testing of prototypes, where students analyze temperature data and use scientific evidence to pitch their sustainable solutions to real-world energy challenges.
Concave MirrorsSolar EnergyEngineering DesignReflectionEnergy PovertyFocal PointSustainability
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Inquiry Framework

Question Framework

Driving Question

The overarching question that guides the entire project.How can we apply the science of concave mirrors and light reflection to design an efficient, portable solar cooker for families living in energy-poor regions?

Essential Questions

Supporting questions that break down major concepts.
  • How can we manipulate light rays to transform solar radiation into concentrated thermal energy?
  • Why is the focal point of a concave mirror considered the 'sweet spot' for solar cooking, and how can it be calculated?
  • How does the curvature of a mirror dictate whether light rays will converge or diverge?
  • In what ways can we apply the laws of reflection to design a low-cost, portable solution for families in energy-poor regions?
  • How do the properties of concave mirrors differ from convex and plane mirrors when it comes to harnessing energy?

Standards & Learning Goals

Learning Goals

By the end of this project, students will be able to:
  • Explain the laws of reflection and how they apply specifically to concave and convex surfaces.
  • Identify and calculate the focal point of a concave mirror to optimize heat concentration for cooking.
  • Apply the engineering design process to build, test, and iterate on a portable solar cooker prototype.
  • Compare and contrast the behavior of light rays when interacting with concave versus convex and plane mirrors.
  • Evaluate the effectiveness of a solar cooker design based on its ability to increase temperature over a set period using solar energy.
  • Discuss the real-world application of solar technology as a sustainable solution for energy poverty.

Next Generation Science Standards (NGSS)

MS-PS4-2
Primary
Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.Reason: The core of this project is modeling how light waves reflect off concave mirrors to concentrate energy at a specific point.
MS-ETS1-1
Primary
Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.Reason: Students must design a cooker specifically for energy-poor regions, requiring them to define constraints like cost, portability, and material availability.
MS-ETS1-2
Secondary
Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.Reason: Students will test their solar cookers and compare their designs against those of their peers to determine the most efficient configuration.

Next Generation Science Standards (NGSS) - Science and Engineering Practices

MS-PS4-3.SEP7
Supporting
Construct, use, and present oral and written arguments supported by empirical evidence and scientific reasoning to support or refute an explanation or a model for a phenomenon.Reason: Students will need to present their prototypes and explain why their specific curvature and focal point placement is effective based on gathered data.

Common Core State Standards (ELA/Literacy)

CCSS.ELA-LITERACY.WHST.6-8.7
Supporting
Conduct short research projects to answer a question, drawing on several sources and generating additional related, focused questions for further research and investigation.Reason: Students will research energy poverty and existing solar solutions to inform their design.

Entry Events

Events that will be used to introduce the project to students

The Silent Fire Mystery

Students enter to find a single, intense beam of light from a concave mirror melting a chocolate bar or popping popcorn without any visible flame or electricity. This 'silent fire' sparks a debate about how light can be concentrated into heat and why this technology could be a lifesaver for families without access to modern fuels.
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Portfolio Activities

Portfolio Activities

These activities progressively build towards your learning goals, with each submission contributing to the student's final portfolio.
Activity 1

Mission Brief: The Global Energy Detective

Before building, students must understand the 'why.' In this activity, students research energy poverty in specific regions of the world where traditional cooking fuels are scarce or dangerous. They will investigate how solar energy can provide a sustainable alternative and identify the specific needs of families in these regions (e.g., portability, low cost, safety).

Steps

Here is some basic scaffolding to help students complete the activity.
1. Select a specific region or country experiencing energy poverty (e.g., parts of Sub-Saharan Africa or Southeast Asia).
2. Research current cooking methods used in that region and the health/environmental risks associated with them (e.g., wood smoke, deforestation).
3. Identify at least three constraints for a solar cooker in this region (e.g., 'must be foldable for transport' or 'must use recycled materials').
4. Create an infographic summarizing your findings to serve as the 'Mission Brief' for your project.

Final Product

What students will submit as the final product of the activityA digital 'Energy Poverty Profile' or infographic that identifies a target region, the challenges families face with current cooking methods, and a list of design requirements (constraints) for their solar cooker.

Alignment

How this activity aligns with the learning objectives & standardsThis activity aligns with CCSS.ELA-LITERACY.WHST.6-8.7 by requiring students to conduct a short research project, and it addresses MS-ETS1-1 by helping students define the human and environmental impact of the design problem.
Activity 2

Mirror Magic: The Ray Diagram Lab

Students explore the physics of light by experimenting with plane, convex, and concave mirrors. They will use ray boxes or laser pointers to visualize how light behaves when hitting different curvatures. The goal is to discover which mirror type concentrates energy (converges) versus spreads it out (diverges), which is essential for the solar cooker design.

Steps

Here is some basic scaffolding to help students complete the activity.
1. Set up a light source and observe how it reflects off a flat (plane) mirror, measuring the angle of incidence and reflection.
2. Repeat the process with a convex mirror and document how the rays spread out (diverge).
3. Experiment with a concave mirror to find the point where all light rays intersect (the focal point).
4. Draw and label ray diagrams for each mirror type, highlighting the 'Principal Axis' and 'Focal Point' for the concave mirror.

Final Product

What students will submit as the final product of the activityA 'Light Reflection Lab Portfolio' containing three annotated ray diagrams showing the path of incident and reflected rays for plane, convex, and concave mirrors.

Alignment

How this activity aligns with the learning objectives & standardsThis activity directly aligns with MS-PS4-2, as students model how light waves are reflected through different materials and surfaces (concave vs. convex).
Activity 3

The Sweet Spot Blueprint

Now that students understand how concave mirrors work, they must calculate and plan their specific prototype. Students will determine the radius of curvature for their intended cooker and use the formula (F = R/2) to find the 'sweet spot' where their cooking vessel must be placed to receive maximum thermal energy.

Steps

Here is some basic scaffolding to help students complete the activity.
1. Select the material for your reflective surface (e.g., Mylar, aluminum foil, or polished metal).
2. Determine the depth and width of your concave shape to calculate the focal point using the geometric properties of a parabola or sphere.
3. Map out where the food container will be held in relation to the mirror to ensure it sits exactly at the focal point.
4. List the costs of all materials to ensure the design remains accessible for families in energy-poor regions.

Final Product

What students will submit as the final product of the activityA technical 'Solar Blueprint' that includes a cross-section drawing of their cooker, the calculated focal point, and a materials list with a budget.

Alignment

How this activity aligns with the learning objectives & standardsThis activity aligns with MS-ETS1-1 (defining criteria and constraints) and MS-PS4-2 (modeling wave reflection), specifically focusing on the mathematical application of the focal point.
Activity 4

Heat Wave: The Prototype Pitch

Students build their prototypes and take them outdoors (or use a high-powered lamp) to test their efficiency. They will measure the temperature increase of a set amount of water over 20 minutes. After testing, students will analyze their data, compare it with classmates, and propose one specific iteration to improve their design.

Steps

Here is some basic scaffolding to help students complete the activity.
1. Construct the solar cooker prototype according to your blueprint.
2. Conduct a 'Timed Burn' test: Measure the starting temperature of water in a small black container and record the temperature every 2 minutes for 20 minutes.
3. Analyze the data: Calculate the total temperature change and the rate of heating.
4. Compare results with a peer's design and identify one feature (e.g., mirror angle, insulation) that made a difference in performance.
5. Create a final presentation that uses your data to 'pitch' your cooker to a mock NGO, explaining how the science of concave mirrors solved the problem.

Final Product

What students will submit as the final product of the activityA 'Performance & Pitch Deck'—a multimedia presentation that includes a time-lapse or photos of the build, a line graph of temperature data, and a persuasive argument for why their design is a viable solution.

Alignment

How this activity aligns with the learning objectives & standardsThis activity aligns with MS-ETS1-2 (evaluating competing solutions) and MS-PS4-3.SEP7 (constructing arguments supported by empirical evidence).
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Rubric & Reflection

Portfolio Rubric

Grading criteria for assessing the overall project portfolio

Solar Heat Hero: Concave Mirror Engineering Rubric

Category 1

Solar Heat Hero Assessment Domains

This category assesses the core scientific and engineering competencies required to design, test, and justify a solar cooker using the properties of concave mirrors.
Criterion 1

Scientific Modeling: Ray Diagrams (MS-PS4-2)

Accuracy and clarity of ray diagrams for plane, convex, and concave mirrors, illustrating the laws of reflection and the behavior of light rays.

Exemplary
4 Points

Diagrams are impeccably drawn and labeled; demonstrates a sophisticated understanding of incident and reflected rays, the principal axis, and the focal point. Explains the physics of convergence versus divergence with high precision.

Proficient
3 Points

Diagrams are accurate and clearly labeled for all three mirror types. Correctly identifies the focal point and illustrates the laws of reflection consistently across all models.

Developing
2 Points

Diagrams show an emerging understanding but may contain minor errors in ray angles or labeling. The distinction between converging and diverging rays is present but inconsistent.

Beginning
1 Points

Diagrams are incomplete or contain significant misconceptions regarding how light reflects off curved surfaces. Labels for the focal point or principal axis are missing or incorrect.

Criterion 2

Engineering Context & Constraints (MS-ETS1-1)

The depth of research into energy poverty and the precision of the design constraints identified for the target region.

Exemplary
4 Points

Provides a comprehensive Energy Poverty Profile with nuanced research into a specific region. Constraints (cost, portability, materials) are highly specific, innovative, and directly address the cultural/environmental needs of the region.

Proficient
3 Points

Conducts clear research into a specific region and identifies logical constraints. The 'Mission Brief' successfully connects the design problem to the real-world needs of families in energy-poor areas.

Developing
2 Points

Identifies a region and basic challenges, but research is surface-level. Constraints are identified but may be generic or lack a clear connection to the specific region's needs.

Beginning
1 Points

Research is minimal or missing a specific target region. Design constraints are vague or do not address the requirements of the engineering challenge.

Criterion 3

Technical Planning & The Sweet Spot

The application of mathematical principles (F = R/2) and technical drawing to determine the optimal placement of the cooking vessel.

Exemplary
4 Points

Technical blueprint is of professional quality, including a precise cross-section. Mathematical calculations for the focal point are flawless and integrated into a logical materials/budget list that maximizes efficiency.

Proficient
3 Points

The blueprint includes a clear cross-section and accurate focal point calculations. The plan demonstrates a thorough understanding of how the mirror's curvature dictates the 'sweet spot' for heating.

Developing
2 Points

The blueprint provides a basic sketch and a focal point calculation, but there may be minor mathematical errors or the drawing lacks technical detail regarding the mirror's depth.

Beginning
1 Points

The blueprint is a simple drawing without technical specifications. Calculation for the focal point is missing, incorrect, or not applied to the placement of the cooking vessel.

Criterion 4

Iterative Testing & Data Analysis (MS-ETS1-2)

The systematic testing of the prototype, data collection (temperature over time), and the comparison of design effectiveness.

Exemplary
4 Points

Executes a rigorous testing process with meticulous data recording. Analysis includes a sophisticated comparison of variables (e.g., insulation, mirror angle) and proposes highly effective iterations based on empirical data.

Proficient
3 Points

Successfully tests the prototype and records temperature data over the full 20-minute duration. Analysis includes a clear line graph and a logical comparison to peer designs to evaluate efficiency.

Developing
2 Points

Conducts a test and records data, but the data set may be incomplete or the graph lacks clarity. Analysis of why the design performed the way it did is limited.

Beginning
1 Points

Testing is disorganized or incomplete. Temperature data is missing or not graphed. Comparison to other designs is superficial or absent.

Criterion 5

Scientific Argumentation & Communication (SEP 7)

The ability to construct a persuasive argument using empirical evidence to explain why the design is an effective solution for energy poverty.

Exemplary
4 Points

Pitch is exceptionally persuasive and professional. Seamlessly integrates scientific principles of concave mirrors with test data to prove the design's viability. Demonstrates advanced leadership in presenting the human impact.

Proficient
3 Points

The 'Pitch Deck' provides a clear, evidence-based argument for the design. Uses temperature data and mirror science effectively to explain why the prototype would help families in the target region.

Developing
2 Points

Presentation is descriptive but lacks a strong persuasive argument supported by data. Science concepts (concave mirrors) are mentioned but not clearly linked to the prototype's performance.

Beginning
1 Points

The final presentation is incomplete or lacks scientific reasoning. It fails to use data from the testing phase to support claims about the cooker's effectiveness.

Reflection Prompts

End-of-project reflection questions to get students to think about their learning
Question 1

What was the most significant challenge you faced when trying to position your cooking vessel at the exact 'sweet spot' (focal point), and what did this teach you about the precision required in engineering?

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Question 2

How has this project changed your perspective on the importance of using low-cost materials and scientific principles to solve global social issues like energy poverty?

Scale
Required
Question 3

Based on your 'Heat Wave' testing results, which area of your design would you prioritize for improvement in a second prototype to maximize efficiency?

Multiple choice
Required
Options
Refining the focal point calculation for better concentration
Increasing the surface area of the reflective material
Improving the heat absorption of the cooking container
Enhancing the portability and durability of the structure
Question 4

Using the 'Law of Reflection' as your guide, explain why a concave mirror was necessary for this project instead of a plane or convex mirror. How did the curvature dictate your results?

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