Here's Why

Make a solar cell from scratch

Over at scitoys.com they have detailed instructions on how to make your own solar cell at home from ingredients you can buy from a hardware shop.

Basically you buy some cheap copper sheeting. Cut two pieces.
You heat one piece for 30 minutes until its covered in thick blackness.
Let it cool slowly for 20 minutes in the air, so the blackness will flake off easily.
Gently remove the black bits under the tap. Don't scrub or it won't work.
Attach an electrical lead to each copper plate with an alligator clip.
Put the two plates in a container with hot water with table salt dissolved in it.
Clip the heated copper plate to the negative and the clean copper plate to the positive terminal of your ammeter.
Expose to sunlight and watch your panel generate microamps of electricity with no fuel!

The flat panel version uses a CD case for the container

How much power does it generate? Simon Quellen Field says:
"Don't expect to light light bulbs or charge batteries with this device. It can be used as a light detector or light meter, but it would take acres of them to power your house. The 0.0000125 watts (12.5 microwatts) is for a 0.01 square meter cell, or 1.25 milliwatts per square meter. To light a 100 watt light bulb, it would take 80 square meters of cuprous oxide for the sunlit side, and 80 square meters of copper for the dark electrode."

About the author: Ian Woolf lives in Sydney, has a degree in Applied Science, worked as a solar astronomer, software engineer, systems programmer, webmaster, research assistant, Cisco CCNA tutor, Physics laboratory demonstrator, Computational Theory lecturer, and subject coordinator; while changing his career to freelance writing and broadcasting. Listen to Ian on the Diffusion radio science show on radio 2SER 107.3FM Monday at 6:30pm in Sydney or streaming audio on www.2ser.com, or listen to the Diffusion podcasts. You should follow me on twitter, here