Rosa Parks' arrest on this day in 1955 sparked the Montgomery Bus Boycott and changed the world. On Dec. 1, Rosa Parks refused to give up her seat on a Montgomery bus
Fire is a chemical reaction that gives off light and heat. It is an example of the chemical process of oxidation.
A fire retardant is a substance that reduces flammability of fuels or delays their combustion. This includes chemical agents, but may also include substances that work by physical action, such as cooling the fuels, such as fire-fighting foams and fire-retardant gels.