77 Before the Gas Pump-Mid

Before the Gas Pump FOCUS Question How does gasoline get to the gas pump?

Fill It Up! Imagine you're driving to school with your family. You're running late, but you have to stop at a gas station first— the car is almost out of gas! You're not alone. Most cars, trucks, and motorcycles run on gas, which is short for gasoline. These vehicles have an internal combustion engine that burns gasoline to produce energy. Gasoline is a liquid made from petroleum, which is also called crude oil. Petroleum is a natural liquid found under Earth's surface that people use to manufacture many products. This makes petroleum a natural resource— something occurring in nature that people find valuable. Just how does gasoline get from inside Earth to your local gas pump? Read on to find out.

From Organisms to Oil Believe it or not, the Sun is the original source of the energy in gasoline. Light energy from the Sun was trapped long ago by plankton— tiny organisms that live in Earth's oceans. Phytoplankton absorb sunlight to make food, as plants do. Zooplankton take in energy when they eat phytoplankton. Plankton and other organisms store energy in their bodies. As these organisms died millions of years ago, their bodies fell to the ocean floor. Over time, layers of sand and mud covered and buried them deep underground. Natural processes inside Earth changed the sand and mud into rocks and the organisms' remains into liquid crude oil and a gas. called natural gas The oil and gas slowly moved up toward Earth's surface through small spaces in the rocks. When they reached rock layers they couldn't pass through, they formed underground pockets called reservoirs. The natural gas rose to sit on top of the denser petroleum. Word Wise Gasoline is called gas even though it's a liquid! Don't confuse it with natural gas, an actual gas that forms below Earth's surface, often alongside the crude oil used to produce gasoline.

Petroleum, natural gas, and other energy resources made from them are called fossil fuels. A fuel is a material burned to get energy. Like fossils, these fuels come from organisms that lived long ago, but fossil fuels are not made up of actual fossils. Extreme heat and pressure completely transformed the organisms' remains as they became fossil fuels. FORMATION OF PETROLEUM 1. Tiny ocean organisms trap and store the Sun's energy. They die and sink to the ocean floor. 2. Over time, the remains become deeply buried under layers of sand and mud. 3. Heat and pressure change the sand and mud into rock and the remains into petroleum and natural gas. 4. Petroleum and natural gas rise and become trapped below a rock layer they can't pass through, forming a reservoir.

Up from Below Petroleum reservoirs occur under dry land and oceans. To reach reservoirs, oil companies drill deep below the surface to rock layers that contain them. Reservoirs are more likely to form in certain places, such as a layer of sandstone below a layer of shale that oil can't pass through. To find the most likely locations for reservoirs, geologists study how sound waves travel underground and bounce off rocks. After geologists locate a possible reservoir, workers use an oil rig to drill narrow holes called wells in the ground. They build large platforms to drill wells in the ocean floor. If a well strikes oil, they use pumps to bring the oil and natural gas to the surface. Do You Know? People in China were drilling oil wells hundreds of meters underground more than 1,600 years ago! They used bamboo pipes to remove the oil from the ground and burned it for heat.

From Rig to Refinery Once removed from the ground, crude oil must get to a refinery to be made into gasoline and other products. But oil rigs are usually located in rural areas or in the ocean, and refineries are far away in cities. What's the solution? Oil companies use pipelines— huge systems of pipes under and above the ground— to move oil across great distances. The Friendship Pipeline is the longest in the world. It transports oil from eastern Russia all the way to Germany. This is a distance of about 4,000 kilometers (2,500 mi.)! Sometimes oil is also carried across the ocean on large ships called tankers.