| Making the solar mirror is simple. The materials you | | | | create a mirror surface on it. This is where potato chip |
| need are: | | | | bags come in handy. It's a cheap way to make a shiny |
| · A rotating platform on top of which a container | | | | reflective surface. |
| can rotate | | | | Clean out the inside of the chip bag with detergent. |
| · Plaster-of-paris (roughly 2.5 litres or 2500 mL) | | | | Then cut pie shaped pieces out of it and glue them |
| · A container with inside diameter roughly 10.5 | | | | onto the surface of the dish, shiny side up. This will |
| inches | | | | create the mirror surface. |
| · A large potato chip bag (with shiny metallic | | | | When the sun is out, orient the dish so that it directly |
| surface on the inside) | | | | faces the sun. The focal point will be roughly 5 inches |
| The liquid plaster-of-paris will be placed inside the | | | | from the bottom. You can test this by moving your |
| container, and the container will be made to rotate | | | | finger along the space above the center of the dish |
| about its center at roughly one revolution per second. | | | | until you feel the hot spot. That's your focal point. It can |
| Due to the nature of the physics, this will cause the | | | | get very hot so be careful. Using a digital kitchen |
| surface of the plaster-of-paris to form a parabolic | | | | thermometer I measured a temperature of over 200 |
| shape. Upon hardening, the plaster will retain this shape. | | | | degrees Celsius! |
| To make the rotating platform you may have to get | | | | This is a small-scale example of concentrated solar |
| creative. One way is to get an old turntable and place | | | | energy. Clearly, there's serious potential for future |
| the container on top, or use a motor-gearbox-pulley | | | | energy needs. |
| combination to rotate the container at one revolution | | | | If you would like to see pictures of the parabolic dish |
| per second. | | | | with explanation included, then feel free to visit the link |
| Once you've made the plaster shape, it's time to | | | | below. |