Revision 1

Cardboard box (shoebox size) Aluminum foil Plastic wrap Black construction paper Thermometer Small marshmallows Chocolate squares Graham crackers Sunny day (>25°C ambient)

1. Line the inside of the cardboard box with aluminum foil (shiny side up). 2. Place black construction paper on the bottom of the box. 3. Create a reflective flap by cutting the box lid at an angle and covering with foil. 4. Cover the opening with plastic wrap to create a greenhouse effect. 5. Place the oven in direct sunlight, angling the flap to direct light inside. 6. Record internal temperature every 5 minutes for 1 hour. 7. After the oven reaches peak temperature, place s'more ingredients inside. 8. Record time to melt chocolate and marshmallow.

Ambient temperature was 28°C. Solar oven reached 45°C after 15 minutes, 62°C after 30 minutes, and plateaued at 71°C after 50 minutes. Chocolate began visibly softening at 38°C (around 10 minutes). Chocolate fully melted by 25 minutes. Marshmallow softened but did not truly melt — became squishy at ~55°C. Graham crackers remained unchanged. Complete s'more assembly was possible at 45 minutes.

We expected higher temperatures. The 71°C peak is below water's boiling point, which limits cooking applications. Insulation improvements (double-wall box, better sealing) could increase temperature. The investigation clearly demonstrates solar energy conversion and the greenhouse effect.