How plates affect our planet: structure of the earth imagine you could travel from one point on earth straight through the center of the planet and out the other side. your journey would be nearly 12,870 kilometers (8,000 miles). along the way, you’d pass through all of earth’s layers: crust, mantle, and core. the crust is the rocky surface of the earth is a thin outer shell, much thinner than the other layers. the land that we see, or continental crust, is about 30 kilometers (19 miles) thick. the earth's crust and the top part of the mantle are broken into ten large plates and many smaller ones. most plates are made of both continental and oceanic crust. the crust floats on a thick layer of rock, almost 100 times thicker than continental crust called the mantle. the solid rock is not like the rock we know. extreme heat makes it move in circles. it flows very, very slowly, but it is enough to cause the plates above it to move over long periods of time. the plates move about 8 centimeters (3 inches) per year. the core is made of a liquid metal outer core that flows around a solid metal inner core. the motion in the outer core creates a magnetic field around the earth. it is the same field that makes a compass work! the core gives off incredible heat, which is one of the driving forces that causes the mantle to flow. compare and contrast earth’s mantle and crust. cite evidence from the text and use at least 2 complete sentences.

a fossil fuel is a fuel formed by natural processes, such as anaerobic decomposition of buried dead organisms, containing energy originating in ancient photosynthesis.[1] the age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years.[2] fossil fuels contain high percentages of carbon and include petroleum, coal, and natural gas.[3] other commonly used derivatives include kerosene and propane. fossil fuels range from volatile materials with low carbon to hydrogen ratios like methane, to liquids like petroleum, to nonvolatile materials composed of almost pure carbon, like anthracite coal. methane can be found in hydrocarbon fields either alone, associated with oil, or in the form of methane clathrates.

the theory that fossil fuels formed from the fossilized remains of dead plants by exposure to heat and pressure in the earth's crust over millions of years was first introduced by andreas libavius "in his 1597 alchemia [alchymia]" and later by mikhail lomonosov "as early as 1757 and certainly by 1763".[4] the first use of the term "fossil fuel" was by the german chemist caspar neumann, in english translation in 1759.[5]

in 2017 the world's primary energy sources consisted of petroleum (34%), coal (28%), natural gas (23%), amounting to an 85% share for fossil fuels in primary energy consumption in the world.[6] non-fossil sources in 2006 included nuclear (8.5%), hydroelectric (6.3%), and others (geothermal, solar, tidal, wind, wood, waste) amounting to 0.9%.[7] world energy consumption was growing at about 2.3% per year. in 2015 about 18% of worldwide consumption was from renewable sources.[8]

the most common type of reef is the fringing reef. this type of reef grows seaward directly from the shore. they form borders along the shoreline and surrounding islands.