Solar Ovens-Part 3

ObjectiveThe third lesson asks the students to refer back to their drawings on the previous worksheet and attempt improve upon their oven design after a general discussion of ways to increase the efficiency of solar ovens. They can compare their design with other commercially available oven types and using additional construction materials actually build their ovens. The apple slice experiment from Part II is repeated and the previously recorded data serves to demonstrate improved performance of their personal oven.

CA Standards--Second Grade

  • Records data in a systematic way

CA Standards--Third Grade

Materials

A sunny day with minimal clouds is optimum.

  • Shoeboxes with lid, aluminum foil (heavy duty and regular), plastic wrap
  • Tape, stapler, scissors
  • Black construction paper, newspaper
  • Toothpicks, straight pin or push pin
  • Meat or other kind of probe thermometer (either digital or analog)
  • Apple slices
  • Chocolate chips--Milk Chocolate, best if not Nestle Toll House

Procedures

  1. Reviewed the cooking factors on the back page of the handout and talked about previous results of apple experiment.
  2. Give each child a chocolate chip and tell them not to chew it. Ask them what the chocolate chip is doing in their mouth and ask why. They should respond with “melting”.
    • Chocolate chips melt at approximately 94 degrees, depending on their formulation. Nestle’s Toll House chips are designed to melt at a higher temperature.
    • The experiment this time will use the chocolate chips with the apple slices as a temperature gauge. Internal oven temperature can be assessed without opening the oven and losing the retained heat. If the chocolate is not melting, the oven will need adjustment i.e. location, reflector, etc.
  3. Students use building materials in different ways to increase the efficiency of their ovens. They can choose which things they want to try. For example,
    • Extra lids or larger box lined with foil to make accessory reflectors.
    • Tape black construction paper to the outside of the box.
    • Fill side spaces with newspaper.
    • Place smaller box inside larger box.
    • Used plastic bag filled with air under liner foil in oven (insulator).
  4. Once construction is complete, give students 1 apple slice, 2 chocolate chips and a small piece of lighter-weight tin foil. Set in the sun for several hours and have students monitor and adjust their ovens periodically.