Coal is a fossil fuel that is formed from the remains of plants that lived and died millions of years ago. Over time, the plantmaterial was subjected to heat and pressure, which caused it to transform into coal.
Types of Coal
There are four main types of coal:
Anthracite: This is the highest quality coal, known for its high carbon content and low impurities. It is often used for heating and in the steel-making process.
Bituminous: This type of coal is widely used for electricity generation and in industrial processes. It has a higher heat content compared to lignite and subbituminous coal.
Subbituminous: Subbituminous coal is used primarily for electricity generation and has a lower heat content than bituminous coal.
Lignite: Lignite is the lowest quality coal, with high moisture content and low heat content. It is used mainly for electricity generation.
Formation of Coal
Coal is formed through a process called coalification. It begins with the accumulation of plantmaterial in swamps and marshes. Over time, the plantmaterial is buried by sediment and subjected to heat and pressure, which causes it to undergo physical and chemicalchanges, ultimately turning into coal.
Reading Standards for Literacy in Science and Technical Subjects
Craft and Structure
Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 6-8 texts and topics.