Sunday, April 10, 2011


Signs of spring:  Our pond is full, so Tobias can finally swim a bit, though there's still lots of ice.  The robins and thrushes have been back for a while.

Tobacco seedlings, about 3 weeks old
 A friend of ours bought a little fan that sits on his woodstove and circulates the warm air.  He assumed that it operated simply because hot air rises.  In fact, it has a small thermoelectric generator running it.  I'd never heard of such a thing and started investigating.  What I found out surprised me.

In very basic terms, it works like this:  When a substance is heated unevenly, so that there is a difference of at least 60 degrees in temperature between one end of it and the other, an electric current is created.  A denser material or greater temperature difference will cause a stronger current. 

According to Collier's Encyclopaedia, thermoelectric systems are used on the moon, where the extreme temperatures make them very efficient.  On a more everyday level: in the 1950's, small units were distributed to people living in remote Siberia so that they could use the heat from their kerosene lamps to run their radios.

It's really free electricity.  I bet my cookstove could run a lightbulb and a radio through the winter if I had the knowledge to build a little generator.  Too bad the makers of that fan wouldn't produce something slightly more powerful and more useful.

Dulsa still likes to lie in a basket

1 comment:

  1. Tulsa in the small basket is hilarious! I guess it hasn't occurred to it that it has outgrown it!