You are sound asleep at 3 o'clock in the morning, when suddenly an incredibly loud bell is blasting in your ears. Replace the fuzz of sleep with a razor sharp mind, because within the next two seconds you need to start running for the truck.

This is the start of a typical day for a firefighter. When the alarm bell rings at the fire station, things have to happen very fast. Today, you are part of the team.

Everyone starts running for the trucks, and you have to suit-up along the way. You jump into your pants, which are already tucked into your boots to save time. Then you throw on your coat and grab your hood and helmet. Your air tank (officially it's called a "Self-Contained Breathing Apparatus" or SCBA) is already in the truck, behind your seat. The truck is rolling as the last person steps on. In as little as sixty seconds after the bell sounds, the truck is screaming out of the fire station.

Special Thanks Many thanks to everyone at Engine Company 19, Atlanta, GA for their assistance.

Sixty seconds ago you were sound asleep. Now you are wide awake, dressed for the fire and going 60 MPH. Two other trucks rolled out of the station with you and they are close behind. The adrenaline is already pumping, and in your head you are rehearsing what you will do when you arrive.

Meet the Enemy To fight fire, we have to understand fire. So, what is this stuff anyway? Simply put, fire is one part of a chemical reaction -- it's a visible, tangible side effect of matter changing form. Fire usually comes from a chemical reaction between oxygen in the atmosphere and some sort of fuel -- something that burns, such as wood or gasoline. The chemical reaction creates a lot of gaseous chemicals (smoke), a lot of heat, and hot glowing particles, which make a visible flame. Of course, wood and gasoline don't spontaneously catch on fire just because they're surrounded by oxygen. The combustion reaction can only happen with a huge boost of energy to start it off. In other words, something has to heat the fuel to its ignition temperature. But once a fire starts, the flame itself provides the necessary heat to keep the reaction going. It will keep spreading, consuming any available fuel. To stop a fire, you need to knock out one of these necessities -- the heat, the fuel or the oxygen. Firefighters do this by: Cooling the fire by spraying it with water Removing the fuel by clearing away surrounding stuff that will burn Smothering the fire by cutting off the oxygen supply with water and foam