November 24, 2012 1:59 pm

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It cooks our food and makes it taste better. It warms our homes and makes our cars go. Yet it can be hard to control. It can destroy a house or an entire forest. It is fire. Fire is both very useful and very dangerous.
Three things are needed to get a fire going. The first is oxygen, a gas that makes up part of air. The second is fuel to burn. Fuel can be anything that will burn. In a campfire, for instance, the fuel is wood. In most car engines, the fuel is gasoline.
The third thing necessary to start a fire is heat. The amount of heat it takes to set a fuel on fire is called the kindling temperature or ignition point. Different materials have different kindling temperatures. Paper has a lower kindling temperature than wood. The tip of a match has a very low kindling temperature. Heat caused by the friction of striking a match against a matchbox makes enough heat to set the match on fire.
When a fuel starts to burn, it gives off a flame. Gases from the hot fuel mix with oxygen in the air to make the flame. Fanning a fire brings in more oxygen to feed the flames.
Early humans used fire hundreds of thousands of years ago. They used fire to cook food, stay warm, and keep wild animals away. People learned to use fire for light. They made oil lamps and candles. They learned to use fire for making things, such as pottery.
It was hard to start a fire before matches and lighters were invented. Some early people learned to make a fire by rubbing sticks together. The rubbing caused friction. Friction makes heat. When the heat was high enough, a fire would start. It takes a long time to make that much heat from friction. That’s why early people were careful to never let their fires burn out. Later, people learned to rub flint and iron to make sparks that can start fires.
We still use fire to cook and stay warm. We also use fire in factories to make things. We burn coal and oil in power plants to make electricity. We use fire in foundries to melt iron and steel. Fire has always been important to the way human beings live.
Some fuels burn faster than others. Gasoline burns faster than wood. Small pieces of fuel burn faster than big pieces. You can use small twigs called kindling to get a campfire started. You add bigger and bigger pieces once the fire gets started.
A fire that is not in control can cause great destruction. Sometimes lightning can start fires. Lightning is a huge spark of electricity that heats up whatever it hits. Lightning can set dry grasslands or dry forests on fire. Wildfires can destroy lots of land. They can burn down beautiful trees.
Wildfires, however, are part of nature. They can keep a forest or grassland healthy. Grasslands grow better after a fire. Some seeds need fire in order to grow and make new trees. Small fires get rid of kindling such as dead leaves and dead trees. In this way, small fires can keep big fires from starting.
Fire is a major danger in homes. House fires can start in many ways. Grease in a kitchen can catch fire. Electrical wires in walls can overheat. The heat can start a fire inside the wall. Cigarettes cause many fires. A cigarette can fall into a sofa, for example. The sofa can smolder, or burn slowly, for hours before it bursts into flame.
Fires in homes, schools, and offices can give off poisonous gases such as carbon monoxide. This gas has no color, odor, or taste. It can kill people. Burning plastics can also give off deadly gases. Most people who die in fires die from poisonous gases.
When a fire breaks out, the fire department comes in. Firefighters use big hoses to pour water on the fire. Water can put out many types of fires. Firefighters break windows to let out gases. The gases could build up and explode. Firefighters knock holes in walls. They look for hidden places where fire could be burning. Firefighters also try to make sure that no one is trapped in a burning building.
It is important to keep house fires from starting. Be sure there are no broken or damaged electrical cords around. There are several important tips to keep in mind:
(1) Put smoke detectors around the house, especially outside the bedrooms. A smoke detector alarm will wake you up if a fire starts while you are sleeping. If there is a fire, get out of the house quickly.
(2) If a fire starts, call 911. The sooner the firefighters get there, the sooner they can put out the fire. This might save houses and lives.
(3) Keep a fire extinguisher handy. If a fire starts, you can spray it before it gets out of control.
(4) Many schools and offices have sprinkler systems. A fire sets off the sprinklers. They spray water all around.
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