A delightful demonstration of the sensitivity his apparatus achieves is shown in the graph at the left. Greg soaked a centimeter of fine thread in water. He then monitored its weight as the water slowly evaporated. Remarkable.
As a service to the amateur community, the Society for Amateur Scientists will supply all the electronics components for this project, including the matched transistors, as well as a set of calibration weights for $60. The package includes the LCD display, but it does not contain a circuit board, the galvanometer coil or the Atmel microcontroller starter kit. To order, call SAS at 619-239-8807. You may write the society at 4735 Clairemont Square PMB 179, San Diego, CA 92117. Or for more information about this and other projects described in "The Amateur Scientist," surf over to http://www.sas.org and click on the "Forum" button.
This article was originally published with the title Down among the Micrograms.