Thursday 25 June 2015

FOSSILS


  • Fossils are formed from plants and animals buried quickly under the earth.When a plant or animal dies it is usually eaten by other living things so that nothing remains.If the plant or animal was buried quickly after death,or even buried alive, it's body may be preserved.

  • A fossil is made from minerals.A dead plant or animal can be dissolved by water.An empty space in the shape of the plant or animal is left in the mud and fills with minerals from the surrounding rock.Sometimes the minerals simply settle in the body, making it harder and heavier.
  • Some fossils look like coiled snakes but are really shell fish.They are ammonites. An ammonite's body was covered by a spiral shell.The body rotted away leaving the shell to become fossil. Ammonites lived in the sea at the same time as the dinosaurs lived on land.
  • Dinosaurs did not just leave fossil bones.Some left whole skeletons. Fossilised teeth ,skin,eggs and droppings have been found.When they walked across mud left tracks behind that became fossils.By looking at those ,scientists discovered how dinosaurs walked and how they could run.
Fossil fuels are burnt every day for all our routine works as a source of energy.Three hundred million years ago land was covered by forests and swamps that did not rot away.Over time their remains were squashed and heated so much that they turned into coal.Today coal is used to work generators that make electricity.

Fossil fuel is a naturally occurring fuel contained in coal,oil and natural gas.It is formed as an organic sedimentary deposit.It contains carbon or hydrocarbon produced by the decomposition of fossilised remains of plants and animals.It can be burned for heat or power.Fossil fuels emit carbon dioxide into the air when they are burned.This contributes to the Green House Effect and Global Warming.These are non-renewable resources.Because we use them much faster than they form naturally.Substitutes and alternative forms of energy are being actively sought and developed as a matter of urgency.Before fossil fuel supplies run out completely or before they become so scarce that price rises make them non-viable as a major energy source.

 FOSSIL FUEL RESERVE
      The quantity of particular fossil fuel that is known to exist based on geological and engineering evidence and that can be recovered under current economic conditions and with available technology.

Estimated recoverable reserves are 1.4 to 2.1 trillion barrels.About 70 percent  of the world's crude oil reserves are with the OPEC countries.

As  the world's population has grown and we have invented petrol - guzzling cars and built fuel-hungry homes, our energy needs have increased dramatically.Total world wide energy use has increased by about 14 times since the early 20th century.