Propose a science project for other DIYers

What can we use if we don't have a pizza box, aluminum foil, or clear plastic wrap?

Use a sturdy cardboard shoebox or shipping box instead of the pizza box, replace aluminum foil with a smooth emergency blanket or extra-dull side of a pie pan taped flat to the flap, and substitute clear plastic wrap with a clear plastic shower curtain, a large zip-top bag stretched tight, or a transparency sheet taped over the rectangular opening.

Why isn't my s'more melting, and how can I fix it?

Check that the plastic window is fully taped and sealed around the rectangular opening, smooth and secure the foil on the flap so it reflects sunlight into the box, re-angle the flap with the stick for maximal sun reflection, and make sure the black construction paper is flat to absorb heat while leaving the box in direct sun for 15–30 minutes.

How do I adapt this project for different ages?

For preschoolers have an adult do the ruler/pencil drawing and cutting while the child decorates and helps tape the plastic window, for ages 6–10 let kids draw the rectangle, cut the three sides with supervision, and assemble the foil and black paper, and for 11+ encourage measuring flap angles, using a thermometer inside the box, timing heats, and recording results.

How can we improve or personalize the solar oven to heat faster or make the project more creative?

Boost performance by adding insulation like crumpled newspaper under the black construction paper, lining more interior surfaces with aluminum foil, placing a small oven thermometer on the black floor to track peak temperatures, experimenting with flap angles using the stick, and decorating the lid before stretching the plastic window to personalize the oven for your DIY.org post.