A very simple device to convert light into sound can be made by wiring a solar cell directly to headphones (or an earpiece). The solar cell converts light into electricity and the headphones convert electricity into sound. The limitation...

A simple demonstration is described which shows how a transistor works. By including the audience into the actual circuit and by lighting LED's it shows the potential of the simple transistor amplifier. The extension to two transistors -...

With the help of some economics metaphors, Habitat Network delves into the scary-sounding "ecological trap" and helps bring it to light.