Can an array of small mirrors focus enough sunlight to melt steel? A solar furnace works by bouncing light from many mirrors onto a single point. The more mirrors you add, the hotter the focal spot becomes.
You cut or buy small mirror chips about 2 cm across. You mount each chip on plywood with silicone and a toothpick spacer. The spacer lets you tilt the angle. Screws beneath each chip allow fine adjustment. You aim each mirror at the same target spot using one central mirror as a reference.
A small 6x6 array is safe for learning the process. A larger array of 256 mirrors or more can reach extreme temperatures. A 4-foot by 8-foot array could create a focal spot 4,000 times brighter than normal sunlight.
Hypothesis
The hypothesis is that a Solar Furnace can generate temperatures high enough to melt steel.
Sunlight can be concentrated to reach extreme temperatures. A solar furnace bounces light from many mirrors onto a single point, and the more mirrors you add, the hotter the focal spot becomes. A large enough array can generate temperatures high enough to melt steel.
In a solar furnace, every mirror is aimed at the same target — a single spot where all the reflected light arrives together. The more mirrors you aim at that spot, the hotter it becomes. A 4-foot by 8-foot array could create a focal spot 4,000 times brighter than normal sunlight.
A solar furnace works by bouncing light from many mirrors onto a single point. Each mirror you add increases the heat at that spot, because every additional mirror sends more sunlight to the same target. A large array of 256 mirrors or more can focus sunlight so intensely that the focal spot reaches temperatures high enough to melt steel.
A solar furnace bounces light from many mirrors onto a single point, and each additional mirror sends more heat to that spot. The more mirrors you aim at the target, the faster the tiny particles in the material there move. A large array of 256 mirrors or more can raise the temperature high enough to melt steel.
Method & Materials
You will need to make or buy a large number of mirror chips of glass or plastic, each one about 2cm or 3cm in size. You will also need a sheet of plywood and a big bag of screws. You will need to cut up some Post-it notes and lay out and drill the holes as shown. You will need to make "hinges" by cutting a number of round wooden toothpicks into 1/8in segments and place a small dollop of silicone sealant at the corner position of a mirror.
You will need mirror chips of glass or plastic, a sheet of plywood, a big bag of screws, Post-it notes, round wooden toothpicks, and silicone sealant.
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After following the steps outlined in this project, you can build a Solar Furnace that can generate temperatures high enough to melt steel. This is an incredibly powerful device, and it is important to remember to keep it covered when not in use, as it can start a fire if left in the sun.
Why do this project?
This science project is so interesting and unique because it allows you to build a device that can generate temperatures high enough to melt steel!
Also Consider
Experiment variations to consider include increasing the size of the array and using thicker plywood to prevent warping.
Full project details
Additional information and source material for this project are available below.
