S'more Power! Engineering a Solar Oven

Day 1: Investigating Solar Energy & Designing Our Oven

Objective: Students will understand the basic principles of solar energy absorption and reflection and begin designing their solar ovens.

(1) Engage (15 minutes):

• S'more Inquiry: Begin by asking students about their favorite way to make s'mores (campfire, microwave, etc.). Introduce the idea of using the sun! Show a brief, engaging video or image of a simple solar oven cooking food.
• Essential Question Introduction: Introduce the Essential Question: "How can we harness the principles of thermal energy transfer, specifically absorption and reflection of radiation, to design and build a solar oven capable of cooking a s'more?"
• PBL Overview: Briefly explain the S'more Solar Oven Challenge and the final goal of designing, building, and testing a solar oven.

(2) Explore (30 minutes):

• Solar Energy Research (Individual/Pairs): Provide students with access to simple articles, diagrams, or short videos about how solar energy works, focusing on:
  • Radiation from the sun.
  • Absorption of sunlight by different colors (dark vs. light).
  • Reflection of sunlight by shiny surfaces (like aluminum foil).
  • The conversion of light energy into thermal energy.
• Guiding Questions for Research: Provide questions to focus their research:
  • What color absorbs sunlight best? Why?
  • What type of material reflects sunlight well? Why would we want to reflect sunlight in our oven?
  • How does the absorbed sunlight make things hotter?

(3) Explain (30 minutes):

• Class Discussion & Concept Mapping: Facilitate a class discussion based on their research. Create a simple concept map on the board or chart paper with student input, connecting terms like "sunlight," "radiation," "absorption," "reflection," "thermal energy," and "temperature."
• Design Considerations Brainstorm: Lead a brainstorming session about factors to consider when designing their solar ovens:
  • Shape of the box.
  • How to use reflective materials.
  • The importance of a dark interior.
  • How to trap the heat inside (insulation - introduce the idea).
  • Where the s'more will go.

(4) Elaborate (15 minutes):

• Initial Design Sketches (Individual): Provide students with paper to begin sketching their initial solar oven designs. Encourage them to label the materials they plan to use and explain why they chose those materials based on the class discussion.

Homework: Continue thinking about their solar oven design and gather any recyclable materials they might want to use for construction (with permission).

Day 2: Building Our Solar Ovens

Objective: Students will construct their solar oven prototypes based on their designs.

(1) Engage (10 minutes):

• Review Designs & Materials: Have students briefly share their initial designs and the materials they have gathered. Discuss any common challenges or interesting ideas.
• Safety Guidelines: Review safety procedures for using scissors, tape, and working with potentially sharp materials like foil. Emphasize the importance of working carefully.

(2) Explore & Explain (70 minutes):

• Solar Oven Construction (Teamwork): Students work in their pre-determined teams (if desired) or individually to build their solar oven prototypes based on their sketches.
• Teacher Facilitation: Circulate around the room, providing guidance, answering questions, and ensuring students are applying the concepts discussed on Day 1. Encourage them to explain the reasoning behind their construction choices.
• Material Adaptation: Be flexible and allow students to adapt their designs based on the available materials. Encourage problem-solving if they encounter construction challenges.

(3) Wrap-up (10 minutes):

• Oven Showcase: Have each team/student briefly present their completed solar oven to the class, highlighting the key design features they incorporated to maximize solar energy transfer.
• Preparation for Testing: Discuss the plan for testing the ovens on Day 3, including the need for a sunny location and the materials for the s'mores.

Homework: Think about how they will test their solar oven and what data they will observe.

Day 3: Testing, Evaluating, and Presenting

Objective: Students will test the effectiveness of their solar ovens, analyze their results, and present their design and findings.

(1) Engage (15 minutes):

• Testing Predictions: Have students make predictions about how well their solar oven will cook the s'more based on their design. What do they expect to observe?

(2) Explore (30 minutes):

• Solar Oven Testing (Outdoor or Sunny Area): Take the solar ovens to a sunny location. Place a s'more (graham cracker, chocolate piece, marshmallow) inside each oven.
• Observation & Data Collection: Have students observe their ovens over a set period (e.g., 15-30 minutes), recording their observations about the s'more (melting, softening, etc.). Encourage them to take notes or draw pictures. Note: Actual "cooking" may vary depending on sunlight intensity.

(3) Explain (30 minutes):

• Results Analysis (Team/Individual): Back in the classroom, have students analyze their testing results.
  • Did their s'more cook? To what extent?
  • What aspects of their design seemed to work well in maximizing solar energy transfer?
  • What challenges did they encounter?
• Redesign Ideas (If Necessary): Based on their observations, have students brainstorm potential modifications or redesigns to make their solar oven more effective.

(4) Elaborate & Evaluate (15 minutes):

• Presentations: Students present their solar oven design, the scientific principles they applied, their testing procedure and results, and any ideas for redesign. Encourage them to use visuals (their oven, drawings, notes).
• Class Discussion: Facilitate a class discussion comparing the different designs and their effectiveness. What common features led to better results? What were some challenges faced by different groups? Connect the results back to the concepts of absorption and reflection.

Differentiation: Offer a limited selection of materials known to be effective for solar ovens. Provide step-by-step instructions for constructing a basic solar oven. Simplify the testing procedure (e.g., focus on a visual observation of melting).

Extension: Encourage students to research more complex solar oven designs (e.g., parabolic reflectors). Challenge them to investigate the impact of different reflective materials or insulation on the oven's temperature. Encourage them to quantify the time it takes for different stages of melting. Have students consider the angle of the sun and how to optimize their oven's position.

• Formative: Observe student participation in discussions, design sketches, and construction process.
• Summative: Evaluate the final solar oven design, the presentation, and student understanding of the scientific principles applied based on the rubric outlined in the PBL description. Look for their ability to:
  • Explain how absorption and reflection of solar radiation were used in their design.
  • Describe their testing procedure and results.
  • Analyze the effectiveness of their oven.
  • Communicate their findings clearly.