lesson
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Every drop of gasoline in a car engine began as microscopic plankton drifting in ancient oceans hundreds of millions of years ago.
How did soft microscopic organisms turn into the thick, dark liquid we pump from deep underground today?
How Crude Oil Formed
When microscopic marine organisms like plankton died millions of years ago, they sank to the bottom of ancient seas and lakes.
Layers of sediment buried them, creating an anaerobic environment—one completely lacking oxygen—which prevented the organic matter from decaying normally.
Over millions of years, rising high temperature and pressure from accumulating rock layers chemically transformed this buried biomass into crude oil and natural gas.
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Because this process takes millions of years, crude oil is a finite resource—we are consuming it vastly faster than Earth can ever replenish it.
Once crude oil forms, what is it actually made of at the molecular level?
The Chemical Composition
Crude oil is a complex mixture of hundreds of different compounds known as hydrocarbons.
A hydrocarbon is a chemical compound containing only hydrogen and carbon atoms, with no other elements bonded to them.
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