The Changing Earth



How do we know that the climate has changed?



In more recent times, geologists and paleontologists have been able to make more accurate measurements of the age of ancient rocks. Trees produce a new ‘ring’ every year, and these can be measured and counted. The width of the ring shows how well the tree grew in any year, reflecting climatic conditions at that time. The rings of even partly fossilized trees buried in bogs can be measured, and these measurements provide accurate records of climate changes over the past 750,000 years. By measuring the radioactivity of once living material, scientists can make accurate measurements up to 40,000 years ago. 



Picture credit: google



 






 



How was oil formed?



Most scientists think that oil was formed from the remains of tiny plants and animals that inhabited the seas millions of years ago. When these creatures died, their remains were buried in layers of rock. Substances in their bodies gradually altered to form oil. Other scientists disagree, and believe that oil formed from carbon-containing materials that were trapped inside the rock when the Earth was formed. Oil is found in rocks buried beneath the continents, and beneath the shallow parts of the oceans. More than half of the world’s known oil resources are in the Middle East. 



Picture credit: google



 


How oil is formed?

Oil is a fossil fuel. It is made from the remains of tiny plants and animals called plankton. The plankton lived in the seas when dinosaurs still ruled the world. Over millions of years the tiny plants and animals have changed into oil.





 



These tiny planktons float in the sea.



Tiny plankton living in our seas today is similar to the prehistoric plankton from which oil is made. Like today’s plant plankton, the tiny prehistoric plants used energy from sunlight to make their food. When they were eaten by animal plankton, the Sun’s energy passed into the tiny animals. So, oil made from prehistoric plankton is actually stored from the Sun.



 



 





 



It takes millions of years for oil to form.




  1. Millions of years ago plankton died and fell to the seabed.

  2. Layers of dead plants and animals built up on to the seabed.

  3. Mud and sand (sediment) sank to the bottom of the sea and covered these layers of plankton.

  4. More layers of sediment piled up on top of the dead plankton. The bottom layers were squashed and became hotter.

  5. Slowly the muddy sediment turned into rock.

  6. The plankton rotted, giving off bubbles of gas, and turned into a thick liquid. This is crude oil.

  7. Crude oil and gas seeped up through the spongy rock, until they reached a solid rock. They stayed under the solid rock in a pool or reservoir.


Black gold



 



 



Every day millions of people use oil in some way. Yet, it is only in the past 150 years that oil has become so important to so many people. Oil is so valuable that it is sometimes called ‘black gold’. Imagine life without plastic and fuel.



 



 



 





 



 



 



Oil was once used in lamps.



Oil has been used for thousands of years. In places where oil naturally seeped to the surface, people collected it. The Ancient Babylonians used it as a mortar for building. The Native Americans used it as glue. In the 1850s, people decided they would not wait for the oil to come to the surface. They would drill for it.



 



 





 



 



 



When cars were invented, more oil was needed.



When the petrol engine was invented the demand for oil grew. Cars became more common. Now, oil has become a vital part of our life. Many oil-fields have been discovered and about 80 million barrels of oil are produced each day.



 



 





 



 



Wars are fought over oil.



Oil has become so important and valuable that wars have been fought over oil-fields. In 1991, Iraq invaded its neighbour Kuwait because it wanted Kuwait’s oil-fields. The UK and USA went to war with Iraq to help free Kuwait. Many of the oil-fields were deliberately set on fire by the Iraqi soldiers. Burning and leaking oil caused a lot of pollution to the environment.


Finding oil



 



 



Oil is very valuable. Geologists, people who study rocks, look for clues that show where oil might be in the ground. They study the shape of hills, the colour of rocks, and the type of soil, to find out if they might contain oil.



 





 



 



This geologist is looking for oil.



Geologists search for rocks that might have oil in them. They can do this by sending sound waves and electric currents through the ground. Geologists can work out where there might be rocks with oil in them by studying how fast the waves and currents travel through the rock.



 



 





 



 



 



Rock samples are drilled out of the ground.



If geologists find rocks that could contain oil, they drill a small test well. A sample of rock called a ‘core’ is brought up to the surface. The rock sample is checked for oil. If there is oil in the rock, the geologists will see tiny droplets of oil clinging on to the rock, a bit like drops of water clinging on to a window after a rainstorm.



 



 



 





 



 



 



Oil is found all over the world.



Oil is found in many countries all over the world. It is found on land and under the sea. The Middle East has two thirds of the world’s known oil reserves. The amount of oil in an oil-field is measured in barrels. Saudi Arabia, in the Middle East, has 262 thousand million barrels of oil.


Oil Drilling deep



 



 



Drilling rigs are used to drill into the ground to reach oil. The rigs have a flat base called a platform. A tower holds up the drilling equipment. The drill is a steel pipe which has a point at the end. This is called a ‘drill bit’.



 





 



Oil-rigs can be built in the sea.



When oil is found under the seabed, an oil-rig is built over the oil-field. Different rigs are used depending on how deep the water is. Oil-rigs with legs are used in water less than 400 m deep. Floating rigs are used in water up to 1,000 m deep. They are tied to blocks on the seabed to stop them drifting away. In even deeper water, rig ships are used, which are kept in place by anchors.



 





 



 



 



The drill bit cuts down through the rock.



As the drill bit bores deeper into the ground, more lengths of pipe are added at the top. The drill bit is covered with diamond dust. Diamonds are very hard and strong, so they help the drill to grind through the rock.



 





 



 



Drills reach oil deep under the ground.



In many oil-fields, the oil is pressed and squashed deep inside the rock. When a hole is drilled into the rock, the pressure pushes the oil upwards and out. The pressure can last for days or years, but eventually the flow of oil drops. Then, pumps are needed to bring more oil to the surface.


From oil-field to refinery



 



 



 



Oil is often found in remote places. It is drilled in the middle of seas, hot deserts and frozen lands. After the oil has been brought to the surface, it is taken from the rig to a refinery. In the refinery it can be turned into many useful products.



 



 



 



 



 





 



Oil is carried along pipes or in huge ships.



Oil is transported to refineries by pipelines. Pipelines run along the seabed or across land. Overland pipeline networks run for thousands of kilometres across North America. Oil travels by sea in huge tanker ships. These ships are nicknamed supertankers. They are as long as four football pitches placed end to end!



 



 





 



 



 



Oil refineries are like huge factories.



At a refinery, crude oil is separated out into different substances. These can be used for many different things.



 



 



 



 





 



 



 



 



The oil is separated out in this tower.



At the refinery, heated crude oil is fed into a tall tower called a fractionating tower. The tower is coolest at the top and hottest at the bottom. The crude oil separates into different substances. The lightest gases rise to the top of the tower and the heavier substances are below. Products such as kerosene and petrol are piped off at different levels within the tower.


Uses for oil



 



Around 85 percent of refined oil is made into different types of fuel. This fuel is used to power vehicles. It is also used to heat our homes, schools and workplaces. In power stations oil is used to produce electricity.



 



 



Oil is used to power these vehicles.



We use one third of the world’s oil to make fuel for transport. Oil burns easily and is a good source of energy. Crude oil is used to make fuels such as petrol, diesel and aviation fuel. These fuels provide the energy that powers cars, trucks, ships, trains and planes.





 



 



 



 



 



 



 



 


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Oil and the environment



 



 



Oil gives us energy and many other things but it also causes pollution. Oil pollution makes the environment dirty. It can harm and kill wildlife and people.



 



 



 





 



 



 



Spilt oil can harm wildlife.



If oil is spilt, it can cause serious damage to the environment and kill many birds and animals. Oil spills from oil tankers at sea are especially harmful as the oil forms a thick, black layer called a ‘slick’. The slick clogs birds’ feathers and the fur of marine mammals, such as otters. Animals can also swallow oil as they try to clean themselves. In the past, large oil spills have destroyed entire coastlines.



 



 


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Cleaner oil



 



Oil is being made cleaner to help protect the environment. Harmful chemicals can be taken out of oil so it pollutes the environment less. Scientists are also finding safer ways to carry oil. They want to prevent oil spills and protect wildlife.



 



 



 



 



 



 





 



 



New oil tankers are safer than old tankers.



Oil tankers carry millions of gallons of oil. If they become damaged in an accident, they can cause huge oil spills. Nowadays, tankers can be built with double hulls. This means that if only the outside hull is damaged, the oil is still held safely inside the inner hull. Soon only double-hulled oil tankers will be allowed to carry oil.



 





 



 



Cleaner oil is being used to heat our homes.



We can use cleaner heating oil in our boilers to heat our homes. It has up to 90 percent less sulphur in it than normal heating oil. This new oil burns cleaner and more efficiently. Cleaner oil helps to reduce pollution.



 



 





 



 



This sludge is left at the bottom of oil containers.                                   



Oil sludge is the thick, sticky substance left at the bottom of oil tankers and storage containers. It is difficult to get rid of. In the past it has been disposed of in landfill sites or burned, but this causes pollution. A new method has been invented which cleans the sludge with steam. This separates the oil from the sludge. This recycled oil is then used to power ships.


Oil Running out

Oil took millions of years to form. Once it is used, it cannot be replaced. We are using it up quickly and one day it will run out. Think about all the things we use oil for. What will happen once the oil has run out?





 



 



This graph shows how oil may run out in the future.



Oil is non-renewable. This means that it cannot be replaced. Once it has been used up, it is gone forever. About half the world’s oil resources have already been used. Oil is expected to run out in about 40 years’ time. In the future, if no more oil is found, less and less oil will be produced. The oil that is left will be much more expensive.



 



 



 





 



 



Many people in cold areas rely on oil to heat their homes.



Many people live in places that have very cold winters. Heating their homes by burning oil keeps them warm. When the oil runs out, many people may have problems heating their homes. They will need to use another source of fuel.



 



 



 





 



Without oil, today’s cars could not run.



Imagine what life would be like without oil. Most forms of transport would stop. Fewer cars, buses, trains, planes or ships could run. This would have a huge effect on our modern life because we rely on oil to power most of our transport.


Saving oil



 



 



We can all help to save oil. If we use less oil, the oil we do have will last longer. Oil is an important source of energy. There are many things we can do to use less energy.



 



 



 





 



 



Hybrid cars use much less petrol.



New hybrid vehicles have been invented which use two or more sources of power. Some of these cars use petrol, and electricity from batteries. The batteries recharge themselves as the car drives along. The car switches from using electricity to petrol and back depending on its speed. Hybrid cars produce much less pollution and are very fuel efficient.



 



Why not try some of these ways to save oil?



 





 



 



 



 



Use less energy at home. Put on a jumper instead of turning on the heating. Houses with insulated attics and lofts save 25 percent more energy.



 



 



 



 





 



 



 



 



Save petrol by using a bus or train instead of going in the car. Walking and cycling keep you fit and save oil.



 



 


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Oil for the future



 



 



Scientists are working on new ways to power the world in the future. New inventions will help us to make the best use of oil. Cars that run on both petrol and electricity will become more common and help to save oil.



 



 





 



 



This rock can be used to make oil.



Oil shales are rocks that contain a large amount of organic matter (remains of dead animals and plants) called Kerogen. Kerogen can be made into man-made oil. Oil shale is found in many parts of the world. To change Kerogen into oil it must be heated to high temperatures. The problem with making oil from oil shale is that it uses lots of energy to heat the Kerogen, and it produces large amounts of waste material.



 





 



 



 



More oil reserves may be hidden under the ground.



Oil companies are constantly searching for new oil reserves. A large oil reserve was recently discovered in Bohai Bay Basin off the north coast of China. In the future it is believed that more oil may be discovered in Russia, the Middle East, North and West Africa and Central South America.



 





 



 



These tiny microbes may be used to get oil out of rocks.



In many oil reservoirs, three quarters of the oil is left behind because it is too difficult to get out. Scientists are working on ways to get the rest of the oil out. One way is to use microbes. These are tiny animals which feed on the nutrients in the oil. They release gas. The gas builds up the pressure in the reservoir which forces more oil out of the rock.



 


What is oil?



 



 



Oil is one of the world’s most important resources. We use oil for energy. We use oil to power cars, trucks, planes, trains and ships. Oil is also used as a raw material to make many things. Every day, we use things that are made from oil.



 



 



 





 



 



Crude oil is thick and sticky. It is made into fuel.



Oil is found underground. When it comes straight from the ground, we call it crude oil. There are several different types of crude oil. They vary in colour, smell and thickness. Heavy crude oil is dark brown or black. It is very sticky like tar. Light crude oil can be clear in colour and is very runny.



 



 



 



Crude oil is used to make all these things.





 



 



 



Plastics



Oil is made into many different kinds of plastic. Foamy plastics, with bubbles of air blown into them, are used to fill furniture.



 



 


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