Grade Level: 4th Grade | Duration: 2 days, 50 minutes each
This two-day engineering design challenge has students work in teams to design, construct, and test functional solar ovens capable of melting chocolate and marshmallows to make s’mores. Through hands-on experimentation, students investigate how different materials convert solar light energy into heat energy, applying the engineering design process to create, test, and iteratively improve their models. The lesson aligns with Alabama College and Career Ready Science Standard 4, which requires students to design, construct, and test devices that change energy from one form to another—specifically, passive solar heaters converting light energy into heat energy.
Learning Objectives
Students will investigate different types of materials to determine which will best convert solar light energy into heat energy, selecting the most effective options for engineering a solar oven. Through the design-build-test cycle, students will create a model solar oven and evaluate its performance by collecting temperature data over time, analyzing results, and determining methods for improvement.
Background & Context
The sun radiates light and heat, collectively known as solar energy. This energy makes life on Earth possible—without the sun’s heat, our planet would freeze. While solar energy has existed as long as the sun itself, humans have harnessed it for thousands of years in agriculture and food preparation.
The lesson provides historical context: the first solar box cooker was built in 1767 by Swiss physicist Horace de Saussure, reaching temperatures of 190°F and successfully cooking fruit. Today, solar cookers are used worldwide in growing numbers. Because they don’t require fossil fuels, solar ovens are safe, produce no pollution, and don’t contribute to deforestation. The sun represents the ultimate sustainable energy source—abundant, convenient, nonpolluting, and affordable.
Key vocabulary includes renewable energy (energy from naturally replenished resources including wind, solar, geothermal, biofuel, and hydro) and sustainable (the concept that renewable resources will never be depleted).
Day 1 Activities & Structure
Engage Phase (10 minutes) – “Brainstorm!”
Students generate as many descriptive words about the sun as they can while the teacher records responses on the board. This activates prior knowledge and builds vocabulary connections. Students then reflect on and discuss three guiding questions: Why do we need the sun? How do we use the sun’s energy? What new ways could we use the sun’s energy?
Explore Phase (35 minutes) – “Design it!”
Students are divided into groups of 3-4 to design and build solar ovens capable of melting marshmallows and chocolate. The teacher distributes the “Solar Oven Engineering Design, Data, & Project Rubric” handout packet and discusses project goals, design expectations, and assessment criteria.
The teacher displays available construction materials but withholds distribution until each group has completed their design sketch and written explanation. Students may handle material samples to inform their planning. Groups sketch their solar oven design on the “My Design” handout page and write explanations of how they expect their design to function.
Once designs are approved, students construct their solar ovens using selected materials. Teachers should emphasize that students are building functional models—they don’t need to be perfect but must be capable of experimental testing.
Evaluate Phase (5 minutes) – “Share it!”
Groups visit one other team’s workspace to view their model. During this peer review, students ask one question about the other group’s design and offer one constructive “tip” or suggestion for improvement. This encourages collaborative learning and exposes students to alternative design approaches before Day 2 testing.
Day 2 Activities & Structure
Engage Phase (5 minutes) – “Discuss it!”
Students turn to neighbors and briefly discuss: What successes do you expect when testing your model today? What challenges do you anticipate? This builds anticipation while encouraging realistic predictions based on their design choices.
Explore Phase (35 minutes) – “Test it!”
Students take their solar oven models outside to a safe, sunny testing area. Each group sets up their oven with s’mores ingredients (graham cracker base, chocolate, marshmallow) for each team member, or as many as will fit inside the oven.
The teacher distributes one flat thermometer and one timer to each group. Students place thermometers inside their ovens and allow 1-2 minutes for accurate initial temperature readings. Using the Data Collection handout, students record initial temperature and observations in the “0 minutes” column, describing the starting state of marshmallows and chocolate.
Groups start 30-minute timers, recording temperature readings and detailed observations at 10-minute intervals (0, 10, 20, and 30 minutes). Students note changes in temperature, marshmallow and chocolate states, and any other relevant observations. At experiment completion, they answer the Results questions: Was there any temperature change? Did the marshmallow or chocolate melt?
Evaluate Phase (10 minutes) – “Share it!”
Groups document proposed design modifications by listing or drawing changes in the Conclusions section of the Data Collection handout. Each team then shares their experimental conclusions with another group, discussing successes, challenges, and lessons learned from the testing process.
Materials Included
The lesson PDF contains a complete “Solar Oven Engineering Design, Data, & Project Rubric” handout packet with three components:
Project Rubric Page
- Header with solar oven icon and “Name of Engineer” line
- Project goal statement: “The goal of this project is to use an alternative energy source to cook s’mores. You will design a solar oven using household items that will cook the s’mores using only the sun’s heat energy.”
- Assessment rubric table with five scoring levels (Above Average to Needs Work) across five criteria: Team Work!, Effort/Creativity, Solar Cooker Design, Presentation, and Data Collection
- Total points tracker and space for teacher comments
My Design Page
- “Name of Engineer” header
- Large “My Design” sketch box with sun icon for detailed drawing of planned solar oven
- Solar panel decorative illustration
- “How It Works” section with three lines for written explanation of design function
Data Collection Page
- “Name of Engineer” header with sun icon
- Instructions: “Use the table below to record the temperature in your oven and observations of the marshmallow and chocolate. You should record your data every 10 minutes.”
- Data table with columns for 0 minutes, 10 minutes, 20 minutes, 30 minutes, and Results
- Two rows: Temperature (with Results question “Was there any temperature change?”) and Observations (with Results question “Did the marshmallow or chocolate melt?”)
- “Conclusions” section at bottom with prompt: “After testing your model, would you make any changes to your design to make it work better next time? Write or draw your thoughts below:” followed by large open response area
Suggested Construction Materials
Teachers should provide a variety of household items for student selection:
- Shoe boxes, pizza boxes, other cardboard boxes or pieces
- Aluminum foil and aluminum pans
- Cellophane and wax paper
- Wooden dowels or skewers (with sharp ends removed for safety)
- Black construction paper
- Duct tape and masking tape
- Scissors
Additional Materials Required
For each group:
- Timer (30 minutes with 10-minute increment tracking capability)
- One flat thermometer (student thermometer or aquarium thermometer style)
- Printed handout packet
For the class:
- Access to sunny outdoor area for Day 2 testing
- S’mores ingredients: marshmallows, graham crackers, chocolate (enough for all students)
- Note: Check for food allergies or dietary restrictions
- Backup: Access to microwave in case of solar oven technical difficulties
This engaging, hands-on engineering project connects abstract energy concepts to tangible, delicious results while teaching the complete design cycle from initial concept through testing and iterative improvement.
Resources & Downloads
STEAM Lab: Engineering a Solar Oven
A PDF file containing everything you need for this lesson.
PDF Document