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.
The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fire naturally occurs when the elements are present and combined in the right mixture, meaning that fire is actually an event rather than a thing. A fire can be prevented or extinguished by removing any one of the elements in the fire triangle. For example, covering a fire with a fire blanket removes the oxygen part of the triangle and can extinguish a fire.