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