Category Geography

Even though aircraft now carry many of the world’s passengers, shipping is still a vital link between countries, particularly for carrying cargo. The biggest vessels are called bulk carriers. They include oil supertankers, some of which are more than 450 metres long. Container ships carry general cargo stored in large steel boxes stacked up like building blocks. These can be unloaded directly on to trucks.

The River Rhine rises in Switzerland and runs along the border between France and Germany, then on through Germany and the Netherlands, meeting the North Sea near Rotterdam. It is one of Europe’s most important industrial waterways. As well as barges carrying cargo, river boats take tourists along the river to see the vineyards and ancient castles on its banks.

Ships cross the oceans on fixed routes called shipping lanes. The world’s busiest shipping lanes link Europe and North America with the Middle East and East Asia. Ships go through the Suez and Panama Canals to shorten their journeys, although supertankers, being too large for the Suez Canal, still travel around the southern tip of Africa.

Modern cargo ships are much larger than vessels of the past, and big, efficient ports with docks (enclosed areas of water) are needed so that their cargoes can be loaded and unloaded as quickly as possible. Some ships take cargoes inland along large rivers and man-made waterways called canals.

Two major canals, cut through narrow necks of land, provide much shorter routes between ports. They are the 165-kilometre Suez Canal in Egypt, linking the Mediterranean Sea with the Red Sea, and the 82-kilometre Panama Canal, connecting the Atlantic and Pacific Oceans.

Canals often link natural waterways and provide a transport route across a continent. The Main-Danube Canal, for example, allows the movement of goods between Eastern and Western Europe. The United States and Canada have more than 41,000 kilometres of waterways linked to the St. Lawrence and Mississippi rivers and their tributaries. The St. Lawrence Seaway connects the Great Lakes, and the cities of Chicago, Detroit, Cleveland and Toronto among others, with the Atlantic Ocean.

Cargo on inland waterways in industrial countries, for example, the River Rhine in Germany, is usually carried by barges which are towed by tugs. Sometimes several barges are strapped together. Barges carry cargoes along the Rhine to and from the port of Rotterdam in the Netherlands, the world’s busiest port. Antwerp in Belgium is the largest inland port in the world. Even though it is 89 kilometres from the open sea, ships of all types load and unload cargoes there.

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Air travel has grown enormously since World War II. Until then, only the wealthy travelled by air. The development of the jet airliner in the 1950s made it possible for everyone to fly to destinations across the world.

The world’s busiest airport is O’Hare International near Chicago in the United States, with an average of one take-off or landing every 35 seconds and nearly 70 million passengers a year. Many of these flights are for people travelling within the United States – about 85 per cent of people travelling within the United States go by air. London’s Heathrow Airport handles more international traffic than any other airport with more than 55 million international passengers a year.

A large modern airport employs thousands of people. Air traffic controllers work in a control tower, directing all aircraft to and from runways and deciding when it is safe to take off or land. They have powerful radar equipment to keep watch over the whole airspace around the airport.

Baggage handlers load and unload suitcases from the aircraft. Once passengers have disembarked, ground crew prepares the aircraft to fly out again, and refuel it while firefighters stand by.

In the terminal, the passengers collect their baggage and go through customs, where officials check that they are not carrying drugs or goods which require import or export tax to be paid.

Airports also handle goods (air freight) that are required to be transported quickly. Warehouses store goods before loading and after arrival, when they are inspected by customs officials.

Security officers use X-ray equipment to check passengers for bombs, guns and other weapons. International passengers also have to pass through immigration where they show their passports and any visas that are required to enter the country. Officials often stamp the passport to show that passengers are entering the country legally. Airports also have lounges and restaurants where passengers can wait for their flights.

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Electricity is a type of energy that gives us heat and light and drives machines. To be useful, electricity must be made to flow in a current. In 1831 the British scientist Michael Faraday used a magnet to produce electricity. He moved a loop of wire over the magnet, causing an electric current to flow through the wire. This principle is used to generate electricity in power stations today. In thermal power stations, coal, oil or gas are burned to boil water, producing steam to drive a generator.

The steam from the boiling water rushes through pipes and turns a bladed wheel called a turbine. The turbine is connected to the generator, which consists of a huge magnet surrounded by copper wire. The turbine makes the magnet spin, thus producing an electric current in the wire.

The water can be heated by other means. The mineral uranium is the fuel used in a nuclear power station. Everything on Earth is made up of very tiny particles called atoms. Splitting the atoms that make up uranium produces a very intense heat for creating steam.

In a nuclear power station, energy is produced by creating a reaction in the nuclei (cores) of uranium atoms. Releasing energy by splitting atomic nuclei is called fission. Each nucleus contains particles called neutrons. Inside the reactor, these hit other nuclei, causing them to split and release more neutrons. This repeated process, called a chain reaction, produces immense amounts of heat energy. Water pumped around the reactor is heated.

Hydro-electric power stations use fast-flowing water to turn turbines. The water from rivers is stored in a reservoir behind a dam. The power station is located in front of the dam. Some of the water is allowed to rush out through pipes to make turbines spin and drive the generator.

SUPPLYING ELECTRICITY

The electricity is sent from the power station along thick wires called cables. They are supported above ground by tall pylons. The electric current is boosted by transformers along the way. The electricity goes to sub-stations from where cables carry it to houses, factories, shops and offices.

The cables from a power station are linked to form a country’s supply network or grid. This allows electricity to be sent to wherever it is needed. Electricity cannot be stored, so a constant supply flows through the cables and wires.

ALTERNATIVE POWER

Coal and oil-fired power stations cause pollution. Fossil fuels, once used up, cannot be replaced. Leaks of radioactivity from nuclear power stations are a potential hazard. So alternative methods for generating electricity are needed. Wind turbines on wind farms, solar power (in which solar panels store sunlight for conversion to electricity), tidal and wave power are all possibilities for the future.

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Fossil fuels – coal, oil and gas were formed from the remains of living things that died millions of years ago and are preserved as fossils.

Coal began to form about 350 million years ago. At that time parts of the Earth’s surface were covered with swamps and lakes. Forests of huge trees and giant ferns grew in the swamps. When these plants died, they rotted down and gradually changed into a type of dark soil called peat. As the centuries passed the peat was buried under layers of sand and mud. Successive layers pressed down more and more tightly until the peat was compressed into layers of hard, black, shiny rock—coal. Folding and faulting of rock layers, the result of Earth movements over millions of years, together with erosion, have brought some coal layers close to the surface and within reach of underground mines.

Coal was first mined as a fuel on an industrial scale in the 18th century when it was used in furnaces to power steam engines and smelt iron. Today it is used in power stations to produce electricity. Coke, a baked form of coal, is a smokeless fuel used in making iron and steel.

OIL AND GAS

Oil is a very important substance. It is used as a fuel in power stations, cars, ships and aircraft, and is an essential raw material for plastics and chemical industries.

Oil and gas were formed in the seas millions of years ago. When the tiny plants and animals that lived in them died they sank to the bottom and were buried under layers of sand and silt. These were gradually compressed into layers of sedimentary rock. The heat action of bacteria changed the remains into crude oil and natural gases.

Pressures in the Earth force the oil up through the sedimentary rock, which has tiny holes in it like a sponge. The oil rises until it comes to a layer of hard rock. If the hard rock has formed a dome over the soft rock, the oil is trapped under it. Geologists looking for oil study the local rock formations and make test drillings. If oil is found, wells are drilled into the ground. When the drill reaches oil, the pressure may be enough to send it gushing up to the surface. If not, it is pumped. The crude oil from the well is sent by pipeline or tanker to a refinery where it is separated into different substances by distillation.

The oil is boiled at the bottom of a huge tank called a fractionating tower. The vapours that are formed float upwards, cool and condense into liquids at different temperatures. Trays at different heights in the tower collect the liquids as they form. These separate parts, or fractions, are formed into different oil products, such as petrol, kerosene and diesel oil. At the top of the tower, gas comes off. The thickest, heaviest products, such as bitumen, used for making roads, sink to the bottom. They can be refined again to make lubricating oils.

The earth contains many minerals that are vital to us today. Minerals are non-living substances such as rocks and metals found naturally in the Earth’s crust.

Some metals, such as gold, can be found at the surface, but others are buried deep in the ground and have to be mined. Copper was one of the first metals to be used by people, but it is brittle and breaks if it is hammered too much. Early metalworkers discovered that if they hammered copper, then heated it in the fire and then hammered it again, it was easier to work with. This was the discovery of a process called annealing.

Some metals have to be extracted from the rock, or ore, in which they are found. The process used is called smelting. The rock is heated to a high temperature so that the metal melts and runs out.

Metals found near the surface are mined by the opencast method but those found deeper down have to be drilled out of the ground. First, geologists determine where the metals are. They carry out surveys of the rock layers beneath the surface, and also measure the magnetism of the rocks and minerals. This is because the magnetic field is stronger in rocks that contain metals such as iron, nickel and cobalt.

INDUSTRY

The word “industry” describes an activity that produces the goods or services that people need or want. There are many different kinds of industry, including mining, farming, fishing, manufacturing and the provision of services for people to use.

Industries fall into three groups. Primary industries are those which extract or grow raw materials, such as mining, fishing, farming and forestry. Manufacturing industries, which turn the raw materials into products such as cars, matches, books and buildings, are known as secondary industries. Tertiary industries include transport, shops, health care, banking, education, leisure and tourism.

In many manufacturing industries around the world, for example, cars, plastics and electrical appliances, machines are used instead of people to make goods. Highly automated industries, as they are called, are using more and more specialized equipment such as electronic technology and industrial robots to increase productivity. This has been partly responsible for increasing unemployment in certain countries. During the last part of the 20th century, Japan and other East Asian countries have developed highly automated industries, including electronics, computers and cars.

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