In this section we will describe how to make a marshmallow roaster, powered by the sun. It can be made from readily available materials, and while it is probably a little safer than the traditional method of roasting marshmallows (over a campfire), it can still start fires, and should be used only by those you would trust with a box of matches.
What we will need:
A page magnifier. More technically known as a Fresnel lens (pronounced freh-nell), this is a piece of plastic almost the size of a notebook page (7 inces by 10 inches) that is used to magnify a page of a book to make it easier to read. These are available in drug and stationery stores, and also in our catalog.
A small cardboard box. The actual size will depend on the focal length of the magnifier. The magnifier we use focuses the sun to a small bright dot at a point 10 and a half inches from the lens. This means that a box 10 inches on a side would be perfect. The actual dimensions are not critical, as we will discuss ways to adjust for large or small boxes.
A package of bamboo skewers to hold the marshmallows. You can also use coat-hanger wire, or long fondue forks.
Some aluminum foil.
Some glue.
Some tape.
Authored by
Simon Quellen Field at
Science Toys, Added: 6 Jul 2008
http://sci-toys.com/scitoys/scitoys/light/marshmallows/solar_roaster.html
