Gasoline
Gasoline makes cars run. This liquid
is very important to us. A car’s engine burns gasoline mixed with air. The
energy released by burning gasoline turns the car’s wheels and makes the car
go.
When the car starts to run out of
gas, it’s time to fill up the car’s gas tank at a gas station. When you’re at a
gas station, you’re probably standing on top of a huge underground storage tank.
The pump brings the gasoline up from the storage tank, and a hose feeds it into
the car’s gas tank.
Our world uses huge amounts of
gasoline. The United States alone uses about 310 billion gallons (1.2 trillion
liters) every year.
WHAT IS GASOLINE?
Gasoline is one of many substances
found in oil, a natural liquid that forms deep underground. When this crude oil
is pumped out of the ground, it’s a mixture of substances called
hydrocarbons. They’re called hydrocarbons because they are made up of
chains of the elements hydrogen and carbon. Different hydrocarbons have chains
of different lengths.
Gasoline is a lightweight liquid at
room temperature, but it becomes a vapor (gas) when warmed up. When gasoline
vapor is mixed with oxygen from the air, a spark causes the mixture to burn
quickly and give off a lot of heat. That’s what makes gasoline a good engine
fuel. A car’s engine turns this heat into energy that turns the wheels.
HOW IS GASOLINE MADE?
Gasoline is separated from crude
oil at factories called oil refineries. There are several ways to get the
gasoline out. The oldest and simplest way is to boil the crude oil. Gasoline
boils at a lower temperature than other parts of crude oil. Gasoline can be
separated because it becomes a gas while the rest of the oil remains
liquid.
The most common modern method for
making gasoline is “cracking.” Longer, heavier hydrocarbon chains can be cracked
into the smaller chains that make up gasoline. Gasoline produced by cracking
burns more completely and evenly than gasoline produced in other ways. It makes
an engine perform better and last longer.
GASOLINE AND AIR POLLUTION
Burning gasoline creates problems.
It puts out gases that cause air pollution. These gases also cause global
warming. Engineers and scientists are searching for solutions to these problems.
Someday you may drive a car that is not powered by gasoline.
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