Hot enough to melt a marshmallow

Cutie Pie was noticing how much cooler he felt when he went into the shade and then again when going into the air conditioned house. I asked if he thought something could be cooked in the sun and that set the whole experiment up with excitement!

Sun Cooking experiment (from 50 science things to make and do by Usborne Activities)

Materials needed:
Tin foil
Clay (we used some playdough that was past its prime)
Cling wrap
Sunny day

Experiment steps:

  1. Line your bowl with tin foil.
  2. Place a toothpick into the ball of clay and carefully place a marshmallow on it. Place this structure in the center of the bottom of the bowl.
  3. Cover the bowl with cling wrap.
  4. Place the bowl outside in a sunny spot, propping it up so that the inside is directed at the sun.
  5. Set a timer for 15 minutes. Observe what happens to the marshmallow.
  6. Carefully remove the cling wrap. Observe how the marshmallow feels. (Use caution, it may be very hot.)
  7. Replace the cling wrap for several minutes longer and make a new observation if desired.

During the 15 minutes hypothesize about what is happening in the bowl, to the marshmallow, to the tin foil, etc.

Cutie Pie hypothesized the bowl would stay cool but that the marshmallow would get bigger. Sweet Pea just wanted to eat the marshmallow.

We observed the inside of the bowl appeared very bright. Cutie Pie believed this was due to the sun shining on it. He made a shadow on the bowl and it was no longer bright. This hypothesis was correct!

Our Experiment outcome:
At the end of 15 minutes Cutie Pie observed the marshmallow appeared to be sliding down on the toothpick. The bowl felt very warm. He then carefully removed the cling wrap and found the marshmallow felt warm as well. (I did touch it first to make sure it would not burn my kiddos.) Sweet Pea said he wanted to touch it, so he did and then he ate it! (Not exactly planned!) After several questions for Sweet Pea we determined the marshmallow was warm, but not hot. It was soft, but not completely melted.

This experiment, called Cooking in the Sun, was found in 50 things to make and do, an Usborne Activities book. My kiddos and I really love the experiments we’ve done in this book. I am in no way affiliated with this publisher, book or author. My family simply finds the experiments fun to do!


  1. Ms. Liz says:

    This is great! One of our favorite things to do is put food in the Sun and see what happens to it… sometimes we don’t do it on purpose though 😉

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