-
Asked by emmagrace to Dalya, Derek, Sarah, Tim, Tom on 19 Jun 2011.
-
Dalya Soond answered on 17 Jun 2011:
Prehistoric sea creatures died and were buried under layers of mud before being eaten by other sea creatures. Instead, under the mud, they are broken down into the hydrocarbons they are made of, which we know today as oil and gas.
Something similar occurs with coal, but this is made from vegetation on land.
-
-
Tim Millar answered on 17 Jun 2011:
Coal was formed after the vascular plants evolved. At that time (about 300 million years ago) large trees and plants were beginning to pump oxygen into the atmosphere and take carbon dioxide out of it. Eventually there was so much oxygen that there was spontaneous burning and a catastrophic event which lead to the loss of the vascular plants for a while and all that locked in carbon became buried. Over time and under pressure the trees were turned into coal, some of which still holds fossilised leaves from the plants that made them.
-
-
Tom Crick answered on 19 Jun 2011:
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms; the age of the organisms and their resulting fossil fuels is typically millions of years.
The fossil fuels, which contain high percentages of carbon, include coal, oil and natural gas.
-
Sarah Thomas answered on 19 Jun 2011:
Fossil fuels are formed from the rmains of prehistoric organisms and plants.
In general oil and gas is formed from the remains of sea creatures that have become embedded within the sea bed. And coal is formed on land from decomposed vegetation.
Over millionss of years the decaying matter is subject to heat and immense pressure as it becomes buried by rock. It is also kept from being exposed to oxygen and other organisms which are the special conditions required for fossils fuels to form!
Fossil fuels are said to be “non-renewable” since they take so long to make, and it is generally believed that within the next 100 years, the cost of obtaining them will make it too expenseive for ordinary people to use – the race is on to find new ways of obatining clean renewable energy!
Comments
emmagrace commented on :
Thank you clever scientist!!