The Amateur Scientist; April 2000; Scientific American Magazine; by Carlson; 2 Page(s)
When set at its maximum temperature of about 260 degrees Celsius (500 degrees Fahrenheit), a kitchen oven is quite capable of rapidly reducing an expensive steak into a sizzling mass of crunchy carbon. This I know from sorry experience. But ordinary ovens are still not hot enough for many research needs. Measuring the organic content of soils is one example. Fertile earth contains all sorts of biochemical and microbial goodies that higher plants cannot live without. To discover how organically rich a soil is, you have to weigh a sample, remove the organics and then weigh it again. The only way I know to eliminate all the organic material is to bake the soil at a high temperature. At around 450 degrees C (840 degrees F), organics break down into their constituent elements, and the carbon bonds to atmospheric oxygen to create carbon monoxide and carbon dioxide gases. The charred residue evaporates, leaving the soil devoid of all the trappings of life.
Because the same process that cooks organic material out of soil will also remove it from the surface of glass, a furnace that approaches 500 degrees C can be used to clean the most intricate laboratory glassware. Likewise, baking sorbents at this temperature drives away chemical contaminants and recharges them for reuse in, say, pumps for producing ultraclean vacuums (the topic of the October 1996 column). Such a furnace would have other uses as well, including melting enamels, activating glass beads for use in chemical separators, annealing glass and metals, and making electrical feed-throughs for laboratory glassware.