Transcript
JULIA COOKE
Carbon is a chemical element, often abbreviated to the letter C. Individual carbon atoms are too small to be seen by eye or even through a light microscope because they’re smaller than the wavelengths of visible light. Carbon is frequently depicted as a black sphere, but is represented in other ways depending on the type of information we want to show, such as chemical bonds or molecule structure.
Carbon is a component of an impressive diversity of molecules, including carbon dioxide and glucose and many biological molecules, including DNA, proteins, fibres, and cellulose, as well as synthetic products such as plastics. We obtain carbon compounds from our food to fuel our bodies and as building blocks to make our cells. Energy from the sun as light and carbon as carbon dioxide from the air can be captured by plants and turned into something ready to eat within a few weeks.
The term ‘organic’ is used in science to describe compounds containing carbon. Some organic energy sources take a long time to form but can store large amounts of energy. We burn wood for heating, but that wood may have taken decades for the tree to accumulate.
When plants and animals die, much of their organic matter decomposes and is broken down into simpler molecules, and eventually, the carbon is released back into the atmosphere as carbon dioxide. But in some conditions, decomposition doesn’t occur, and the carbon is trapped and stored.
Coal, a fossil fuel, began forming between 360 and 280 million years ago when huge areas of peat bogs and swamps grew and then were buried. Over time, they were subjected to very high pressures and heat, which transformed the plant material into coal. Crude oil is formed when large quantities of tiny plants and animals, zooplankton and algae, are buried under sedimentary rock and subjected to high pressures and heat.
Between 180 and 140 million years ago, during the Jurassic period, the carbon for much of today’s crude oil was deposited. When we burn fossil fuels in power plants and cars, we’e using energy from the sun and carbon fixed through photosynthesis hundreds of millions of years ago. They can’t be replaced quickly, as hundreds of thousands to millions of years are needed to accumulate the solar energy and carbon to form coal and oil.