The invisible material believed for many years to be the source of heat. To heat a body was to add phlogiston phlogistication; to cool it was to take phlogiston away dephlogistication. Today that seems pseudoscientific, but at the time, it was an explanation of what was observed in heating and cooling.<\/p>\n
The theory had its problems this became more evident as chemists developed quantitative methods. Some substances, wood for example, lost weight on burning, leaving a dephlogisticated residue ash; others such as metals gained weight. Priestley\u2019s discovery of oxygen provided the key. Lavoisier showed between 1770 and 1790 that it was invariably involved in any combustion, that burning was the addition of oxygen. So if the wood ash and the combustion gases were both weighed, there was an increase in weight, that of the added oxygen. When a metal was burnt, oxygen was added oxidation; when iron ore was \u201cburnt\u201d in a furnace to give shining metallic iron, oxygen had been removed from the ore reduction. Careful quantitative experiments showed that the sums added up, and by 1800 Lavoisier\u2019s oxygen theory was generally accepted and the phlogiston theory abandoned.<\/p>\n
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The invisible material believed for many years to be the source of heat. To heat a body was to add phlogiston phlogistication; to cool it was to take phlogiston away dephlogistication. Today that seems pseudoscientific, but at the time, it was an explanation of what was observed in heating and cooling. The theory had its […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-211201","post","type-post","status-publish","format-standard","hentry","category-p"],"yoast_head":"\n