Fossil Fuel Use
AP Environmental Science
Energy is so important to our country, we have an entire department dedicated to securing our energy
needs, and thus our prosperity. Visit the Department of Energy website, or the energy information
administration website, and research the following questions and topics.
What are fossil fuels?
1. You are probably familiar with the three fossil fuels…but how familiar are you with their formation?
Would you actually find fossils in fossil fuels? Describe how coal, oil, and natural gas are formed.
Differentiate between conditions that cause their individual forms. (6 points)
Coal - forms through the remains of plants that live in swampy forests hundreds of millions of
years ago. When the plants die, they sink to the bottom of the swamps and are eventually
covered by layers of dirt and water. The weight of the dirt and water on top packs down the
plants, and heat and pressure eventually transform the plants into coal.
Oil - Heat and pressure from layers of animal and plant remains covered by sand, silt, and rock,
turn these layers into crude oil or petroleum.
Natural gas - formed when remains of plants and animals accumulate in thick layers on the
earth's surface and ocean floors, and are buried under sand, silt, and rock over time.
Typically, coal is formed from land-based plants in bogs and swamps, while natural gas and oil
are formed from tiny marine organisms like algae or phytoplankton.
2. How many states in the U.S. currently mine coal? How much of the world’s known coal
reserves are found in the U.S.? (2 points)
There are 21 states that currently mine coal in the US. The US has the largest coal reserves in the
world, accounting for 23% of the reserves as of 2023.
3. Geologists differentiate between four types of coal. Describe the different types of coal in terms of
structure and energy density. (8 points)
Lignite - Lignite has the lowest energy density and is high in moisture content, and is soft and
crumbly in texture.
Sub-bituminous coal - This coal has a higher energy density than lignite, with a lower moisture
content, and is softer than bituminous coal.
Bituminous coal - this coal is common, it is higher in energy density, it has a glossy look, and it is
used in many industries.
Anthracite - this has the highest energy density, the lowest moisture content, it is the hardest and
shiniest, and it burns cleaner and hotter.
