What it is
"Napalm" means any petrochemical — for example, gasoline, kerosene, or benzene — that has had chemicals added to it to thicken, or gel, it and make it function more effectively as an incendiary. Napalms are stickier, and burn hotter, than unadulterated hydrocarbons. As the Oxford English Dictionary writes, it is "A thixotropic gel consisting of petrol and this thickening agent (or some similar agent), used in flame-throwers and incendiary bombs; jellied petrol."
Who invented it
Harvard Chemistry Professor Louis Fieser and his associate E. B. Hershberg on Valentine's Day 1942 in a top secret university war research laboratory in the basement of the Converse Chemistry Laboratory on Oxford Street in Cambridge, Massachusetts. Fieser and Hershberg and their colleagues tested the first napalm bomb on the Harvard College soccer field, between the Business School and the football stadium, on July 4.
Why it was invented
For use as an incendiary weapon. Its creators said they expected it would be used against structures. "I couldn’t foresee that this stuff was going to be used against babies and Buddhists. The person who makes a rifle … he isn’t responsible if it is used to shoot the President," Fieser told journalist John Lannan in November, 1967.
Where it has been used
In most of the world's major military conflicts since its creation: most frequently, widely, in the greatest quantities and over the longest period of time by the United States, but also by Cuba, Peru, Bolivia, Brazil, Britain, France, the Soviet Union, Portugal, Israel, Egypt, Turkey, Iraq, India, Ethiopia, Thailand, El Salvador, and Argentina, among others. Its first use in combat was on 15 December 1943 in Sicily when U.S. troops incinerated a wheat field believed to shelter Germans. Napalm bombs first saw combat on 15 February 1944 when the U.S. attacked Japanese forces in the town of Pohnpei, capital of the eponymous Micronesian island 2,500 miles southwest of Hawaii and 1,800 miles northeast of Australia. Its most recent use was by U.S. forces during the 2003 invasion of Iraq.
Napalm is legal to use on the battlefield under international law. Its use against "concentrations of civilians" is a war crime.
Is an herbicide. It not napalm.