Age range: 8–14
Time: 30 minutes setup + 15–45 minutes cooking (sunny day)
Concepts: solar energy, heat transfer, greenhouse effect
Goal
Concentrate sunlight to melt chocolate and marshmallow for a mini s’more.
Materials
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Clean pizza box (or shoe box)
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Aluminum foil
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Plastic wrap or clear food bag
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Black paper
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Tape and scissors
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Stick to prop lid
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Graham crackers, chocolate, marshmallows
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Thermometer (optional)
Safety
Adult cuts with scissors/knife. Use on a stable surface outdoors. Hot contents!
Steps
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Reflector flap: Cut three sides of the pizza box lid to make a hinged flap.
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Line it: Cover flap underside with smooth foil (shiny side out). Line box interior bottom with black paper.
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Window: Tape plastic wrap over the opening to seal the “oven.”
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Load: Place s’more inside on a small plate. Close lid; prop the foil flap to reflect sun in.
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Aim: Adjust angle until the brightest light hits the s’more.
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Cook & record: Check every 5–10 minutes; note melt time and any temperature if using a thermometer.
What’s Happening
Foil reflects sunlight; the clear window traps heat (greenhouse effect); black paper absorbs and re-radiates heat.
Troubleshooting
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Windy? Add extra tape around the window.
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Weak heating? Re-aim often; the sun’s angle changes.
Extensions
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Compare foil vs. no foil; black vs. white paper.
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Try different box sizes and chart warm-up times.
