If someone challenged you to come up with a demonstration of the 20-odd per cent proportion of oxygen in Earth air, could you do it?
I'd fail. Fortunately a little refresher course has shown up in the CAMZ class notes from Kensington High freshman science class.
"Some iron filings were placed in a test tube which was inverted in a dish of water. The original level of the water was noted. The apparatus stood for several days.." |
Hold it right there. See the illustration, below? How are the iron filings being made to stick to the inside bottom of the test tube? Spit?
Okay, I can't do a demo; how about understanding some practical application, such as a household hot-water system from that era?
At left, the lovely coil (great shading!) is being heated via piped natural gas, yes? The tank on the right has convection currents going. |
So far, so good. But what's this "coil in range," at the far right? The kitchen stove was used as a parallel heat source. Therefore that tall convection tank had to be sitting in the kitchen. I've never seen any setup of that kind. Can someone send in a photo of such a system in place?
And what kinds of stoves burning what sorts of fuel were used in these systems: wood, coal, natural gas, electricity?
When did modern hot-water heaters, gas or electric, become available and replace these systems?
I'm going read up on demos by hunting up my copy of Michael Faraday's Royal Institution Christmas Lectures from a hundred years previous to this. Or did I give that wonderful volume away to some offspring?
Michael Faraday set the standard for scientific demonstration. |
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