Early in my career, before I obtained work as a full time teacher, I taught night school to a Grade 11 chemistry class. I wished to show them how white phosphorous was a waxy solid and could be cut with a knife. My cylinder of phosphorus lay in a pneumatic trough safely covered by water but I had not prepared a knife ahead of time. All I could find was a pair of scissors. I thought I might be able to cut a piece of the phosphorus off with them and proceeded to do that by lifting the cylinder out of the water and cutting. However, a good deal of scissor pressure was required to make any impression on the phosphorus. Little did I realize that this pressure would raise the temperature high enough to reach the low ignition point of 40 C. In a few moments the first flames occurred and so, instinctively I stepped to the sink and turned on the tap to put out the flames. Big mistake! The water stream just caused flaming bits of phosphorus to break off and land on the desk, on the floor and on my hand! We all watched wide-eyed as the flames burned all they touched, including my hand. The class was almost over anyway so I dismissed the students and drove myself to the hospital with, as I later learned, third degree burns. Nobody there knew what to do, especially as they saw white smoke still emanating from under my fingernails. I knew that carbon disulfide was a solvent for phosphorus so I drove back to the school and soaked my hand in it. I’m not sure how effective this was, as white smoke still came out from under the fingernails, but perhaps not quite as much.
Learning by Accident – White Phosphorous
Categories: General Interest