Aborigines are the earliest known inhabitants of a country.
The wearing away of the landscape by the movement of debris carried by rivers, glaciers,the sea or wind. See also corrasion, erosion.
Rain that contains a high proportion of pollutants, notably sulphur and nitrogen oxides, and has a pH value of less than 5.6. These pollutants are produced into the atmosphere from factories, power stations burning fossil fuels, and car exhausts. when mixed with water, they become weak solutions of sulphuric and nitric acid. Because the ecology of streams and forests is finely balanced, acid rain can kill all the fish and other creatures in a stream, leaving it clear-looking but lifeless, and destroy vast tracts of forest. It has particulary hit Scandinavia and Germany.
A photograph taken from above the ground, usually from an aeroplane or balloon. There are two types of aerial photograph - an oblique photograph, where the camera is held at an angle, and a "bird-s eye view", where it is held vertically. Aerial photographs are useful in preparing maps. See also satellite image.
Human management of the environment to produce food. See farming.
A small island in a river or lake; also called an eyot.
Land bordering a river, on which alluvium is deposited.
Fine sand, gravel or clay transported in suspension and deposited by rivers or floods.
An alp is a high mountain; also, a gently sloping mountain pasture above the steep side of a valley but below the snow line in summer. The Alps are a mountain range in Switzerland and neigbouring countries. Alpine landscape is the landscape of alpine areas.
A rippled, white or grey layer of cloud.
An instrument which measures wind speed.
The southern frigid zone, bounded by the antarctic circle, within which there is at least one day of the year when the sun does not set.
The line of latitude around the earth which marks the boundary of the antarctic frigid zone. It is approximately 66° south.
An arch in folded strata. The opposite of a syncline.
An area of high atmospheric pressure from which air rotates outwards.
A pair of places on the earth's surface that are directly opposite to each other. For instance, the North pole is antipodal to the South pole. The Antipodes Islands (southeast of New Zealand) are almost antipodal to the British Isles.
A layer of permeable rock which has a layer of impervious rock beneath, so that it holds water. The level below which the aquifer is saturated is called the water table. See also artesian basin.
Arable farming is farming which involves ploughing or tilling of land, such as the production of cereal crops; contrast with pastoral farming and mixed farming.
A group of islands.
The northern frigid zone, bounded by the arctic circle, within which there is at least one day of the year when the sun does not set.
The line of latitude around the earth which marks the boundary of the arctic frigid zone. It is approximately 66° north.
A knife-edged ridge separating two cirques.
A shallow syncline with a layer of permeable rock covered over by layers of impermeable rock, so that rainwater entering the permeable rock where it is exposed at the surface will sink into the rock until it becomes saturated. Wells can be sunk to obtain the water from the central parts of the basin; they are called artesian wells. The water in the aquifer can be forced out by the pressure of the water in the surrounding higher land at the edges of the basin.
A collection of maps in a book. The name comes from the mythical giant, Atlas, whose picture appeared on the title page of Gerard Mercator's 16th century book of maps.
The thin layer of gases that surrounds the earth. It is divided into layers called the troposphere, stratosphere and ionosphere.
The weight of atmosphere pressing down on each unit of area; the unit of pressure is the bar, which is divided into 1000 millibars. It is measured using a barometer. At sea level, pressure is about 1000 millibars. An area of lower than than average pressure is called a depression, or cyclone. An area of higher than normal atmospheric pressure is called an anticyclone.
A coral reef, typically found in the pacific ocean, shaped like a ring or horseshoe and surrounding a lagoon.
Moving curtains of light seen in the sky, caused by electrical discharges near the poles, in the upper ionosphere. Near the north pole it is called the Aurora Borealis, and near the south pole it is called the Aurora Australis.
The third season of the year, when fruits are gathered in, and the leaves of deciduous trees fall.
The return movement of seawater off the beach after the breaking of a wave. See swash.
The difference between the value of the imports of a country and the value of its exports, over a stated period. See international trade.
A collection of sand, gravel or mud near the mouth of a river or harbour.
A crescent-shaped sand dune. Barkhans are found in the Turkestan desert. The horns of the crescent point downwind.
An aneroid barometer connected to a recording instrument which draws a graph recording changes of atmospheric pressure with time.
An instrument for measuring atmospheric pressure. An aneroid barometer is one which has a box containing a partial vacuum. As the atmospheric pressure changes, the shape of the box changes too, and this is linked to a pointer.
A dam across an estuary, used to manage the water in it, to control flooding or to harness the power of the waves.
A dark, fine-grained igneous rock.
The area of land drained by a river and its tributaries. Also, an area of synclinal rock structure. See also Artesian Basin.
A large mound of igneous material that has risen into the earth's crust from a great depth. As it cools slowly, large-grained rocks such as granite are formed. Later, the batholith may be exposed by weathering.
An indentation in the coastline with a headland on either side.
A sluggish watercourse, the marshy offshoot of a lake or river. A term commonly used in the southern United States.
A strip of land sloping gently towards the sea or a lake, especially when sandy or pebbly.
The angle between a given direction and the north measured clockwise from the north line. It is obtained using a compass with a scale, and is between zero and 360 degrees.
The scale used to measure the streugth of wind from 0 to 12. NAME KM PER HOUR 0 calm air less than 1 1 light air 1 - 5 2 light breeze 6 - 11 3 gentle breeze 12 - 19 4 moderate breeze 20 - 28 5 fresh breeze 29 - 38 6 strong breeze 39 - 49 7 moderate gale 50 - 61 8 fresh gale 62 - 74 9 strong gale 75 - 88 10 whole gale 89 - 102 11 storm 103 - 114 12 hurricane above 117
The surface which separates one layer of sedimentary rock from another.
The part of the earth, from the upper atmosphere to the depths of the ocean, that contains living organisms. It provides a variety of habitats.
The number of live births per 1000 people in a population per year.
A wave that rushes strrongly up the estuaries of certain rivers e.g. the Severn bore.
The mass of debris dragged along by a glacier as ground moraine, and dumped when it melts.
A wall built at right angles to the line of a beach, to keep sand in place by reducing longshore drift.
Rock consisting of angular fragments cemented together by finer material.
A wind, between 2 and 6 on the Beaufort scale. In a light breeze (force 2), wind is felt on the face, and leaves rustle. In a gentle breeze (force 3) the wind extends light flags. A moderate breeze (force 4) raises dust and loose paper. In a fresh breeze (force 5) small trees in leaf begin to sway. In a strong breeze (force 6), large branches are moved by the wind, and it is difficult to open umbrellas.
An outlier of a mesa in arid regions.
Containing calcium carbonate; chalk and limestone are mostly calcium carbonate, so the soils of chalk downlands are calcareous.
A large crater formed by the collapse of the cone of a volcano. It may become dotted with smaller cones, and it may become filled with water - see crater lake.
Air in which winds, if any, are less than one kilometre per hour. Force 0 on the Beaufort scale. In calm air, smoke rises vertically.
A man-made course for water, used for transportation.
A deeply-cut river valley in an arid region.
A headland projecting into the sea.
A system of industry or agriculture where capital (investment) is the main input, and a large workforce is not required. Capital intensive industry tends to replace labour intensive industry. Market gardening is an example of capital intensive farming.
A series of waterfall s
A hollow place in a rock. Caves were used as dwelling places in prehistoric times. Caves can be formed by the action of rainwater on limestone, or by the force of waves or wind eroding soft rock that lies under a more durable stratum.
A big cave, found especially in limestone country.
Soft white limestone. It is a pervious sedimentary rock, made primarily of marine shells. It forms rolling downlands and cliffs in the south of England, and strata of it dip under the Thames valley to form an artesian basin.
A fohn wind. A warm west wind from the Pacific ocean and descending the eastern slopes of the Rocky Mountains, making winter grazing possible.
See convection.
Other names are corrie, cwm. A steep-walled hollow at the head of a glacial valley. It is caused by erosion at the place where the ice started to move downwards.
Detached small high clouds, looking like tufts of white hair, which are found at heights of 5 to 13 kilometres (20,000 to 40,000 feet) and are normally composed of ice crystals.
A large, organised centre of population. The concentration of commerce, industry and society in one place creates problems of organisation, so that the development of cities needs to be planned to a large extent.
A soil composed of very small particles of sediment, less than.005 millimetres across. Rocks made from such fine particles are also called clays. Kaolin, or China Clay, which is found in Devon, is used for making pottery and toothpaste.
A steep slope of rock caused by erosion, either by waves of the sea or by a river (see river cliff ). A sea cliff forms where the rocks of the shore are durable. A cliff can be overhanging, where a strong cap rock protects softer rock underneath, which is cut away by the waves.
The typical conditions of the atmosphere at a place, based on the average of observations noted over a number of years. - contrast with weather. See also continental climate.
The patterns of climate in an area can change over a long period of time. The Sahara desert was once much smaller than it is today, and it is still growing. It is thought that the climate is influenced by human activity such as the production of CFCs and other "greenhouse gases" - see greenhouse effect. It is difficult to measure such influences because climatic change can take place over thousands or even millions of years, and accurate measurements have only been made in recent decades. See also ice age, little ice age.
A block of limestone in a limestone pavement. See also Gryke
A mass of small water droplets or ice crystals in the atmosphere, formed by the condensation of water vapour. This usually happens when air containing water vapour rises and cools, as a result of convection or because it is forced over hills. There are several different types of cloud. high (5 to 13 kilometres) : cirrus middle (2 to 7 kilometres) : altocumulus low (0 t 2 kilometres) : cumulus, cumulonimbus, stratus, stratocumulus.
A solid, dark, carbon-rich rock that is an important fossil fuel. It is made from the remains of plants that grew in swamps at a time called the carboniferous period, more than 280 million years ago. There are various types: Coking coal is suitable for making coke (a grey brittle residue left when the coal is heated in a furnace to remove gases), which is used in iron and steel production. Bituminous coal is high in carbon, and burns well.
The broad area of land that borders the sea, also known as the shore. Various features are found at coasts - see bay, beach, breakwater, cliff, estuary, fiord, harbour, port, stack, wave-cut platform. These features are made by the action of waves and currents (see longshore drift ), by the rising or sinking of the land at the coast, or by human activity.
A mountain pass
See cyclone.
Goods which can be exchanged for other goods; the basis of trade. Examples are crude oil, cotton, rubber, grains, metals and other minerals.
Land which is shared between all the people of a community, instead of belonging to an individual.
The area around a town or city from which people travel to work in the centre.
A device containing a magnetised needle which indicates the direction of the north magnetic pole. From the knowledge of which way is north, any other direction can be found; see bearing. Compasses are used in ships and aircraft, and by surveyors.
A forest of evergreen trees, which bear cones and have needle-shaped leaves. Evergreens are able to tolerate colder weather than deciduous trees, so coniferous forests form a vast band covering most of Canada, Siberia and other northern lands, with many lakes, bogs and rivers. This band is separated from the tundra by the timberline, beyond which trees will not grow.
A major division of the earth's land; that is: - Africa, Asia, Europe, North and South America, and Australasia. Sometimes Europe and Asia are considered to be one continent, called Eurasia, because there is no sea separating them.
The climate associated with the centres of large continents, especially Central Asia and Eastern Europe, and North America
A theory, proposed in 1912 by Alfred Wegener, that the positions of the continents are not fixed, and that at one time there was one super-continent (which he called Pangaea),which broke up to produce the present continents. See plate tectonics.
The seabed bordering a continent. A broad, relatively shallow platform from the coast to a depth of 100-200 metres, with a steep drop at its edge.
A line on a map joining places that are the same height above sea level.
Farming where ploughing is done along contours to conserve water by reducing runoff, and to reduce soil loss from surface erosion.
A large urban area produced by the growing together of several towns and villages.
The transfer of heat from one place to another by the movement of heated air or water. When air is heated it becomes lighter, and so tends to rise and spread out. Colder air moves in to take its place. This is the cause of the wind. Similar effects in water produce ocean currents. Convection is responsible for many atmospheric effects, such as clouds and thunderstorms. See also cyclone, anticyclone.
An organisation owned by the people who use its services. It is formed when individuals pool their resources, to get a better deal than they could otherwise obtain. The first consumer cooperative was started in Lancashire in 1844, the Rochdale Society of Equitable Pioneers. Farming cooperatives are important in many third world countries. The Kibbutzim (plural of kibbutz) in Israel are agricultural cooperatives.
A ridge in the floor of an ocean, made from the built-up skeletons of coral polyps, small animals which attach themselves to the sea bed. In the right conditions, with clear, well-circulating water that is not too rough, the reefs become very large. Reefs are found especially around islands in the Pacific. The Great Barrier Reef near Australia is more than 1200 miles (2000 km) long. See also atoll.
1) The earth's core is probably composed of iron and nickel, at a high temperature.
2) A core sample is used in prospecting and scientific examination of underground rock. It is a cylindrical piece of rock obtained using a special drill.
See cirque.
A term similar in meaning to abrasion (literally, abrasion means scraping away and corrasion means scraping together), but usually used to describe the EFFECTS of abrasion - e.g. the widening or deepening of a valley.
A small, sheltered inlet or bay.
A rocky outcrop on a valley side.
A hard outcrop of rock which was sculpted by a glacier during the ice age, and the mass of material eroded from the rock and deposited downstream to produce a tail. Compare with Roche Moutonnee
A bowl-shaped depression caused by the impact of a meteorite, or the mouth of a volcano. A large crater produced when a volcano explodes or collapses is called a caldera.
A lake occupying the caldera of an extinct volcano. Crater Lake, Oregon, USA is a spectacular example.
A small inlet on the coast, or arm of a river.
A crack or fissure in a glacier, resulting from stress produced by movement. Crevasses can be up to 20m wide and hundreds of metres long.
A drawing showing the heights of all the points along a line, which can be produced from a contour map.
The earth's crust is the outermost layer of rock, only.1% of the total.
An artificial drainage channel.
A heavy dark cloud, very deep from top to bottom, "heaped up" like cumulus, and usually associated with rain.
A "heaped up" cloud with an almost-flat base and a top that sometimes looks like a cauliflower.
- see Ocean Current; also convection.
See Corrie.
The circulation of air currents around, and towards, an area of low atmospheric pressure. Cyclones move anticlockwise in the northern hemisphere and clockwise in the southern hemisphere. They are associated with rain and snow, because they consist of warm air, containing water vapour, which rises over the surrounding colder air, forming fronts. The leading front, where warm air is rising over cold, is called a warm front. The trailing front, where cold air is sliding underneath the warm, is called a cold front. Where the warmer air has been detached from the ground, so that at ground level there is only colder air, the front is said to be occluded.
A pastoral farming system producing milk (usually from cows) and milk products such as cheese, cream and yogurt.
A bank or mound built to keep water back; Dams can be used to produce reservoirs of drinking water, to control the flow of a river or to produce hydro-electric power. In Holland, dams have been built in order to reclaim land from the sea. See also barrage, polder.
A line that follows the 180° meridian from Greenwich, apart from some detours to avoid land areas. By international agreement, when a ship or plane crosses the line eastwards it goes forward a day, and going westwards it goes back a day. This is necessary because, when it is midnight in England, for example, in countries to the east of England it is after midnight and to the west it is before midnight.
The number of deaths per 1000 population in a year.
Trees which shed their leaves in autumn, and are generally broad leaved. Contrast with coniferous forest. Large deciduous forests are found in Europe, The Eastern United States, and Northeast Asia. See also tropical rainforest.
A Narrow pass, also called a gorge or ravine.
The large-scale removal of trees without replacement. Deforestation causes problems in many third world countries.
A fan-shaped deposit of alluvium at the mouth of a river. There are many different kinds of delta, with different shapes and structures. The Mississippi forms a "bird's foot" delta projecting out into the Bay of Mexico. The Nile delta is arcuate i.e. it forms a curved boundary with the sea. The Amazon delta is estuarine, i.e. it takes the appearance of an estuary with a large number of islands.
The study of trends in population.
The laying down of sediments.
A country in Asia, Africa or South America which is undergoing modernisation, urbanization and industrialisation.
drops of water vapour condensed out of the atmosphere and settling on the ground. The temperature at which dew forms is called the dew point.
An equatorial belt of low atmospheric pressure, towards which the trade winds blow.
A dormitory town is one where people live who work in a nearby city.
A landscape of gently rolling chalk hills.
The removal of water from the land surface. Artificial drainage is the use of ditches to transform marsh or swamp land into useable farmland. See culvert, dyke, dam, polder. Natural drainage is into streams and rivers, or into the pores or fissures of pervious rock.
See continental drift, or drift mine.
A mine in which the access is via an inclined tunnel instead of a vertical shaft, allowing vehicles to enter. An example of this type of mine is found in the Selby coalfield, an eastward extension of the West Yorkshire coalfield.
A shortage of water, caused by a long period of dry weather.
A valley which has been filled by an arm of the sea, as the sea level has risen. A drowned u-shaped valley is a fiord. A drowned v-shaped valley with tributaries is a ria.
A feature of limestone and chalk landscapes, where valleys are found in areas that have no streams or rivers. The valleys may date from a time when the area was wetter, or during the ice age when the subsoil was frozen, allowing surface streams to exist although the limestone is permeable. See also Wadi.
A low hill of sand, found at the sea shore or in a desert. It forms because blown sand grains move more slowly over a sandy surface than over a rocky surface, and are more likely to settle, so that sand has a tendency to accumulate. See Barchan, Seif dune.
A natural movement of the earth's crust, also called a tremor. Earthquakes occur mostly in fault areas, where one plate of rock is sliding under or along another one. The force of an earthquake is measured using the Richter scale.
The first element of a grid reference.
The study of living things and their relationship with their environment.
A natural system, consisting of living organisms and their environment.
- see migration
The basis of many economies. Some areas depend on the production of coal or oil for their income, and in others the cost of energy is the biggest influence on industrial development. See also geothermal energy, nuclear power.
Physical surroundings, which influence the development or growth of people, animals or plants; living or working conditions.
An imaginary great circle running around the earth, midway between the two poles. The sun at midday is always almost overhead at the equator, so the weather is generally hot, except in mountainous areas. The equator separates the Northern Hemisphere from the Southern Hemisphere.
The wearing away of the land by sun, rain, wind, frost, running water, moving ice and the sea. Erosion of soil is a serious problem in many farming areas, especially where deforestation has taken place. Contour farming is often used to minimise the problem. Contrast with weathering. See also abrasion, corrasion.
A boulder that has been transported by a glacier, so that it is different from the surrounding rocks.
The pouring out of magma, ash or gas by a volcano.
A ridge of high ground. The ground to one side of the ridge, which slopes gently, is called the dip slope. The ground to the other side slopes more sharply, and is called the scarp slope.
A low, winding ridge of pebbles and sediment on a formerly glaciated lowland. It marks the course of a stream of meltwater that ran beneath the glacier.
The broad mouth of a river where it enters the sea, and where the tides have an influence on the river.
A continent, stretching from the Ural mountains in the East to the Atlantic Ocean in the West.
A group of countries, of which Britain is a member, forming a single market with a coordinated economic policy.
A type of vegetation that does not shed leaves in the autumn. Coniferous forests are evergreen.
Product or service sold to a foreign country. One country's export is another country's import.
A small island in a river or lake; also called an ait.
The widespread starvation caused by combinations of drought, floods, war and other disasters, or an unequal distribution of resources.
The business of cultivating land. - See Arable farming, mixed farming, dairy farming, pastoral farming.
A break in the Earth's crust along which movement can take place. The strata on one side of a fault do not line up with those on the other side. Earthquakes happen along fault lines.
An upland moor or rough grazing area.
A sketch of a landform or landscape made while at the site.
A long narrow inlet of the sea with steep sides. It is caused by the sea filling a U-shaped valley that was carved by a glacier.
A flood caused by a very rapid downpour of rain.
The covering of an area of land by water.
The flat area in the lower course of a river, over which it meanders.
A dense mist.
A warm dry wind; the Chinook is a well-known Fohn wind.
A bending or buckling of rock strata. See syncline and anticline.
Mountains that have been formed by large-scale folding of rock.
The succession of organisms that feed on one another, starting with producers, i.e. plants, and progressing through herbivores (plant eaters) to carnivores (meat eaters).
A place where a river or stream can be crossed. Settlements often grow up around a ford, e.g. Oxford.
A large uncultivated tract of land that is (or was originally) covered with trees and underwood. See deciduous, coniferous forest.
Coal, oil and natural gas.
The boundary between two masses of air of different temperatures. In a warm front, warm air is rising and sliding over colder air. In a cold front, cold air is sliding under warmer air. Fronts are found associated with cyclones.
A wind, between 7 and 10 on the Beaufort scale. In a moderate gale (force 7) inconvenience is felt when walking against the wind. A fresh gale (force 8) breaks twigs off trees. In a strong gale (force 9) slight structural damage occurs; chimney pots and slates are removed. In a whole gale (force 10) trees are uprooted and considerable structural damage occurs.
Energy obtained from underground, in the form of hot water or steam, is called geothermal energy.
A hot spring throwing up a column of water at intervals. Geysers are found in Iceland, New Zealand and the Yellowstone area of the United States.
The covering of an area with ice sheets and glaciers. Areas near the poles and in high mountain areas are glaciated today. Others were glaciated in the past, during the ice ages (e.g. the Lake District area). There are many features produced by glaciation - see esker, moraine, arete, corrie, fiord, etc.
A slowly moving river of ice. Found in mountain areas and near the poles, they covered a larger area during the ice ages, and carved out many features. See Glaciation.
The warming of the earth's atmosphere caused by an increase in the level of carbon dioxide and other "greenhouse gases". See climate change.
A sphere representing the earth; a more accurate way of mapping the earth's surface than a flat projection.
A narrow pass between cliffs or hills, also called a defile or ravine. Gorges in limestone country are usually formed by the collapse of a cavern.
The measure of steepness of a line or slope.
An igneous rock which forms deep below the surface of the earth, Because it cools slowly, it has large crystals.
Small pebbles and sand deposited by water.
Large expanses of land covered mostly by grass, such as tropical savanna, pampas, prairie and steppe.
Land around a town or city on which development is restricted by legislation. The purpose is to maintain some open area, which would otherwise be lost to urban sprawl.
See global warming.
The Meridian which passes through Greenwich, in east London. Longitude is measured in degrees east or west of this meridian, so that it is also called the zero, or prime, meridian.
A way of specifying position on a map, using two numbers. The first number is the eastings, and the second is the northings.
Water held in the bedrock of a region. In some desert areas groundwater is found which originally entered the ground a great distance away and many years before. Groundwater is an important resource where surface runoff is low. See artesian basin, oasis.
See breakwater.
A gap between blocks of limestone ( clint s) in a limestone pavement.
A warm ocean current which comes from the gulf of Mexico and passes close to Britain, making the climate warmer than it would otherwise be.
The location preferred by a species.
A tributary valley which comes to an abrupt end in a steep slope leading down into another valley. It is caused by deepening of the main valley, especially by glaciation.
Precipitation in the form of pellets of ice, formed when rain freezes during its descent.
A promontory of resistant rock along the coastline. See bay, cape.
One half of the earth. The earth is divided into a northern and a southern hemisphere by the equator. When it is winter in the southern hemisphere, it is summer in the northern, and vice-versa.
A rounded elevation of the earth; a small mountain. Hills were often chosen as sites for settlement and fortification in the past, because they were easily defensible.
See fell. When valleys are useful for communication (roads and rail), they become built up and the hills between are left for farming, as in South Wales.
The land behind a port which supplies the exports and makes use of the imports which go through the port.
Frozen dew, forming a white powdery surface.
The region around a persons home. This might be the local town, or county, or an even larger area.
A measure of the amount of moisture in the air. Relative humidity is measured on a scale from 0 to 100; 100 means complete saturation. Humidity is measured with a hygrometer.
Devastating weather, with winds of force 12 on the Beaufort scale.
The cycling of water, from ocean to atmosphere to groundwater, to streams, lakes, and rivers, and back to the ocean. It is generally an annual cycle, i.e. water from the sea finds its way back within a year, but in some areas groundwater can be trapped for many years.
A period of extensive glaciation caused by a drastic cooling in the climate.
A covering of permanent ice over a relatively small land mass, e.g. Iceland.
A permanent covering of ice over a substantial continental area. There are ice sheets covering Antarctica and Greenland.
A mass of ice that has broken off a glacier and is floating in the sea. Nine-tenths of an iceberg are below the surface.
Rock which originated as lava. E.g. granite, pumice. It may be volcanic rock, in which the lava solidified at the surface, or it may have cooled slowly deep below the earth. There are several formations associated with igneous rock - see batholith, dyke.
Impermeable rock is rock which has no pores, or which has pores through which water cannot pass. Water might still pass through the rock via fissures, however, so it may be pervious. The opposite of impermeable is permeable.
Impervious rock is rock which water cannot pass through. The opposite of impervious is pervious.
Product or service bought from another country. See also export, hinterland, international trade.
Existing industries tend to be sited where they are for historical reasons, e.g. The cotton mills were originally sited in Lancashire because of the humidity of the climate and the availability of water and coal for power. There are good reasons for companies to stay in established areas, such as the existence of a skilled workforce, or of established customers or suppliers. This can lead to what is called industrial inertia, the tendency of industries to stay put. However, in choosing a new site for an industry, it is important to consider all the costs of transportation, rates and so on, and the available grants and incentives, and choose a site which is optimal in some respect.
The period in Britain's history, stretching from 1780 to 1900 or thereabouts, when the invention and application of industrial processes transformed Britain into the first industrial society, and caused a mass migration fron the countryside to the towns.
The production of goods by workers in factories. Heavy industry is concerned with large-scale processes such as steelmaking. Light industry involves smaller units of production, and is easier to set up.
The works needed to support the operation of an organisation or system. The infrastructure of a city, for example, is the roads, railways, drainage, water and electricity supply, schools, and so on.
The heavily built up area at the centre of a city, usually containing offices and shops, light industry, terraced housing and flats.
Farming which uses large amounts of labour and/or capital relative to the size of land involved, so that the yield of the land is maximised. Market gardening, providing the needs of a nearby town, is intensive farming. Fertiliser, insecticide and fungicide and irrigation are used to increase crop growth.
See date line.
The exchange of commodities between countries for money or for other commodities. See import, export.
A body of igneous rock which has forced its way up into the earth's crust, as magma, from the mantle below. It forms batholiths, dykes and sills.
The very high layer of the earth's atmosphere, above the stratosphere, which reflects radio waves.
The artificial application of water to land. It has been done since ancient times, to grow crops in areas of low rainfall. In the Nile area water was hoisted out of the river and into irrigation channels. In some desert areas walls were built along hillsides to channel the occasional downpours towards fields. Nowadays much irrigation is mechanical, or involves the building of a dam to create a reservoir from which water is piped.
An area of land which is surrounded by water.
A small island.
A line on a map joining places with equal pressure.
A line on a map joining places with equal rainfall.
A line on a map joining places with equal temperature.
A narrow strip of land joining two larger bodies of land, for example the isthmus of Panama.
A vertical or almost-vertical fissure in sedimentary rock, or in igneous rock that cooled rapidly, especially in sills and dikes. Joints in limestone are enlarged by rainwater to produce grykes - see limestone pavements. Note that a joint is much smaller than a fault.
Eroded limestone scenery without surface water, characterised by caves, sinkholes and underground rivers. Named after an area of Slovenia where such landscape is typical.
A small depression in a glacial outwash plain, probably formed when a detached block of ice became wholly or partly buried, and later melted.
A system of agriculture or industry where labour is the main input, rather than capital (see capital intensive ). For example, rice farming in south-east Asia is labour intensive.
A large dome of land where a dome-shaped igneous intrusion has pushed up the strata of rock above it.
An area of shallow, quiet water connected to the sea, but separated from it by sand bars, barrier islands, or a coral reef.
An inland body of slow-moving or standing water which occupies a depression in the ground. See crater lake, loch, oxbow lake, ribbon lake, tarn.
The broad category of activity that takes place in an area, for instance, farming, forestry, industry or residential. Some land use is controlled by legislation covering planning permission, green belts and national parks.
The general appearance of an area, which depends on the geology and climate, and on the use to which land is put. Landscapes which are determined by the geology include chalk landscape - gently rolling downs and white cliff s; Karst, alpine landscape and so on.
An indication of how far from the equator a place is. It is measured in degrees north or south of the equator.
Magma brought to the earth's surface by a volcanic eruption. There are several different types. Acidic lavas are viscous, and flow slowly. Basic lavas are more liquid. Lava flows can be a serious problem for people living in the shadow of a volcano.
A low ridge built alongside the bank of a river or stream to protect the adjacent land from flooding. The bes known system of levees, and one of the largest, is the one built alongside the lower reaches of the Misissippi. Levees vere built along the left bank of the Nile in ancient times.
Winds of between 1 and 5 kilometres per hour; force 1 on the Beaufort scale. In light air the direction of wind is shown by smoke but not by wind vanes.
A visible electrical discharge in the atmosphere, caused when a part of the atmosphere acquires a charge sufficient to overcome the resistance of the air. It is usually followed by thunder.
Sedimentary rock made mostly of calcium carbonate. Chalk is a soft limestone, and coral reefs are made of calcium carbonate, but the word is usually reserved for harder rock with horizontal bedding planes and vertical joints. Limestone is permeable, that is, it can absorb water. It is also slightly soluble, so in time the water will dissolve caverns. Another interesting thing about limestone is that many fossils can be found in it. See Karst, limestone pavement.
A flat surface of limestone becomes eroded with a pattern of grooves called clints and grykes, which give the appearance of a pavement.
The area between high and low tide marks on a beach.
See industrial location.
A Scottish word, meaning a lake or an arm of the sea (such as a fiord ).
A very fine silt deposit, transported by the wind prior to deposition.
An indication of how far east or west a point is, measured as degrees east or west of the Greenwich meridian.
The movement of material along a beach caused when waves hit the beach at an angle. The waves transport sand and pebbles diagonally up the beach, but when they roll back, or are carried back by the backwash, they travel directly down the slope of the beach.
An Irish form of the word loch.
Molten rock. When it reaches the surface of the earth it is called lava. If it cools down and solidifies it becomes igneous rock.
The direction pointed to by a magnetic compass.
The part of the earth that lies below the crust and above the central core.
The making of articles using physical labour and machinery.
A representation on a flat sheet of the features of an area, or of the whole world. When a large area is to be represented, the fact that the earth is curved must be taken into account, and a suitable projection must be used. Symbols are used to refer to different features such as towns and roads. Sometimes colours are used to indicate land type or use (physical), or the boundaries of countries (political). Contours or hachuring can be used to indicate relief features. A collection of maps is called an atlas. See also Ordnance survey, scale.
A metamorphic rock produced when limestone is subjected to great pressure. Marble can be very attractive, with various colours and patterns of "veins", and is much used for building. It can be polished to give a very smooth surface.
A place to which people travel periodically to buy and sell goods. The area from which people will travel to obtain goods and services at a town is called the market area. A town which supplies goods and services to the surrounding area is called a market town.
Market gardening provides the needs of a nearby town. It is intensive farming. Fertiliser, insecticide, fungicide and irrigation are used to increase crop growth, costly items making market gardening capital intensive.
A wetland ecosystem with poorly drained mineral soil, and plant life consisting mostly of grasses.
A central mountain mass; e.g. the Massif Central of France.
A maximum and minimum thermometer is one which has two markers, one which is pushed up as the temperature rises and stays in position when it falls, and one which is pushed down as the temperature falls and stays in postition when it rises.
A bend in a river. Named after a river in Asia Minor which bends around quite a lot.
The Mediterranean sea is a sea which separates Europe frm Africa. The name is Latin, and means "middle of the Earth"; It was at the centre of the known world at the time when it was named. The area around the Mediterranean sea has a distinct pleasant warm climate, which is called a Mediterranean climate.
A line (actually half of a circle) on the surface of the earth going from one pole to the other. The Greenwich meridian is the one that passes through Greenwich, East London.
A high, rocky, steep-sided table land. See also Butte.
A metamorphic rock is one which has been changed over a period of time by the application of heat and pressure
A rock which travels through space and enters the earth's amosphere, becoming heated until it glows. Some large craters were made by meteors, but most meteors burn out high up in the atmosphere, above the ozone layer.
The study of weather. The word meteor originally referred to any atmospheric phenomenon.
The moving of people or animals into (immigration) or out of ( emigration ) an area. Migration is one of the factors which influences population, along with birth rate and death rate. Some animals, especially birds, migrate annually to find a suitable habitat.
A place where minerals ( rocks containing useful or valuable material) are dug from the earth. It can be on the surface, or deep underground, with a shaft or tunnel leading down to it. See drift mine, opencast.
A substance obtained by mining. An element or compound that is found naturally. ores are minerals which contain a metal.
The obtaining of material from the ground by digging - see mine.
An optical illusion caused by the bending of light by layers of air at different temperatures. Mirages are seen in deserts, or can appear on any flat ground in hot weather, the reflection of the sky giving the appearance of water.
A fine suspension of water particles in the air; a thin fog.
Arable and pastoral farming taking place together
The growing of just one crop over a large area.
The monsoon is a wind which changes direction with the season, in southeast asia. It is from the southwest (wet) in summer, and from the northeast (dry) in winter. The name comes from the Arabic for " season ". It is caused by low pressure over central Asia in summer, and high pressure in winter. The monsoon season is the rainy season that accompanies the southwest monsoon, in summer.
A line of gravel left behind by a glacier when it retreats. Terminal moraine runs across the path of the glacier and marks where it stopped for a while. Lateral moraine runs lengthwise along the valley carved by the glacier See also esker.
An opening, e.g. of a cave, or where a river meets the sea. The mouth of a river can be a delta or an estuary. It can have a bar, or spit.
Very fine rock particles holding water. Wet soft soil. It can form a sediment at the mouth of a river, building up a delta or bar.
An area set aside because of it's outstanding beauty, and protected by law against excessive development.
An arch which is formed by the action of waves eroding a headland. Durdle door, in Dorset, is an example. Eventually the arch may collapse, leaving a stack.
A fossil fuel gas, consisting of hydrocarbons, which is obtained from many areas where oil is also found, especially in the North Sea. It is used as domestic or industrial fuel.
See tide.
An area designated for urban development, to provide employment in a depressed region or to provide overspill accomodation for a large city.
People who wander from place to place, without a settled home, live a nomadic existence. They are called Nomads. The Bedouin Arabs are an example.
A resource is non-renewable if the supply of it is limited and there is no process which might replace it; for example, oil and most minerals are non-renewable.
The direction to the left of an observer who faces the rising sun. It is marked in the sky by a star, the pole star, which always appears towards the north while the other stars seem to revolve around it. In most maps, north is at the top. The hemisphere centred on the North Pole is called the Northern Hemisphere. There is a magnetic North Pole, near the true North Pole, which can be found using a compass.
The second element of a grid reference.
Energy obtained by splitting atoms of radioctive nuclear fuel (fission). The main fuel used is uranium. Nuclear power stations do not produce smoke and do not cause acid rain, but there are concerns about their safety and about the difficulty of getting rid of waste products, some of which are highly radioactive and will stay radioactive for many years.
A fertile area where water is found in a desert. The plural is oases. Nomadic tribes wander between oases.
A very large expanse of water; it is usually reckoned that there are five oceans, the Atlantic, the Pacific, the Indian, the Arctic and the Antarctic.
Ocean currents are produced by convection in the water. A cold current can cause a cooling of the climate in an area. For instance, penguins are found in the Galapagos islands, even though they are almost on the equator, because a cold current from the Antarctic flows past the islands. On the other hand, the gulf stream is a warm current that makes the climate of Britain warmer than it would otherwise be.
A usually flammable greasy liquid obtained from animals, plants or mineral deposits, used as a lubricant, fuel, foodstuff etc. Mineral oil is a fossil fuel obtained from wells sunk in areas where the oil has been trapped in an anticline containing porous rock.
Mining at the earth's surface.
The organisation responsible for producing official maps for use by the government and army. It also produces detailed maps for tourists and for general use. The symbols used on these maps should be known in order to make best use of the maps.
A lake produced when a meander in a river is cut off at both ends, the river taking a new, shorter course.
Molecules of oxygen containing three atoms instead of the usual two. The ozone layer is a layer of the atmosphere, above the stratosphere but below the ionosphere, which contains an accumulation of ozone. This helps to absorb ultra-violet radiation from the sun. The ozone layer has been getting thinner in recent years, especially around the south pole, and this is a problem because exposure to ultra-violet light can be harmful. The main cause of the "hole" in the ozone layer seems to be the effect of chlorofluorocarbons (CFCs) which are used in refrigerators, aerosols and some industrial processes. Because of this, most nations have agreed to stop producing CFCs by the end of the century.
Vast treeless grassland plains in South America, south of the Amazon river.
Pastoral farming is the keeping of animals which graze on pasture land, e.g. sheep, goats or cattle.
Land on which grass is grown, used for grazing animals.
An almost-flat area, with some features sticking out from the surrounding landscape.
An area of land that is almost surrounded by water. It is joined to neighbouring land by an isthmus.
Permanently frozen subsoil within the arctic circle.
Permeable rock is rock which contains small pores (spaces), so that water can pass through it via the pores. Permeable rock is also pervious.
Pervious rock is rock which is either porous ( permeable ) or fissured, so that water can pass through. The opposite is impervious. The best known pervious rocks are chalk, limestone and sandstone.
The study of physical features of the landscape - how they are formed, etc.
Most towns and roads nowadays are only built after careful consideration has been made of their effect, and a study of the alternatives. New towns in particular have been planned to get the right balance of industry and residential areas. Planning involves dividing an area into zones - industrial zones, residential zones and business zones, and forecasting traffic so that the right size of roads can be built.
According to plate tectonics, the surface of the earth is divided into a number of plates which move slowly together or apart.
The theory that the surface of the earth is divided into a number of plates which move slowly together or apart. See continental drift.
A column of hard volcanic rock left when an extinct volcano is eroded away.
The deep water at the foot of a waterfall.
In holland, a piece of low-lying, reclaimed land. It is made by building dykes to enclose a stretch of water, then pumping the water out into canals. Polders are usually very fertile, and are used for farming.
There are two poles on the surface of the earth, which are places which do not move as the earth rotates. These poles lie on the axis around which the earth rotates. They are called the North Pole and the South Pole. The magnetic poles are close to the true north and south poles, and can be found using a compass.
Human activity and exploitation of natural resources often lead to some dangerous or unpleasant substances getting into the environment. This is called pollution.
The number of people living in an area. It is affected by the birth rate, the death rate, and migration.
A hole worn in solid rock by the abrasion of gravel rotating in an eddy of running water; also, a deep hole in limestone.
The almost flat, mostly treeless grassland of North America. Similar to the Pampas of South America and the steppes of Asia.
Water falling on the earth in the form of rain, snow, hail or dew.
The sector of the national economy that produces raw, unmanufactured and unprocessed materials. Agriculture, fisheries, mining and forestry are primary activities. The development of a country is characterised by a decrease in the number of people employed in the primary sector, and an increase in employment in other sectors.
A way of representing the earth's surface on a map. Some projections are designed to keep areas constant, e,g, the Mollweide projection. Mercator's projection gives correct compass bearings, making it suitable for navigation. A globe cannot be represented exactly on a flat surface, so every projection introduces some distortion.
An igneous rock made from acid lava, which floats in water because it is filled with cavities containing gas.
A place where stone is obtained from the earth's surface.
Condensed moisture in the atmosphere which falls as visibly separate drops. It can be measured with a rain gauge.
Dense tropical forest which contains a large variety of life forms. The rich vegetation is supported by the regularity of the rainfall, and is not an indication that the soil is good - the soil in rain forest areas is usually quite poor. Much rainforest is subject to deforestation, as settlers clear areas for cattle ranching or other farming. This is a problem for several reasons. Once the rain forest is lost, it is unlikely to be renewed, and the soil, without its covering of trees, is soon eroded away.
A jar and funnel arrangement, with a scale, used to measure the amount of rain falling in an area in a given time.
An area of broken, turbulent water in a river channel.
A narrow pass, also called a defile or gorge.
Land that was once sea, but has been drained; see polder.
A band of coral wnich builds up offshore in tropical areas. See coral reef.
An area of land that has a unifying characteristic, or that is marked by clear natural boundaries. See home region.
A planning policy made by a country, or by the region concerned, to improve the areas in which they have problems e.g. of unemployment, low income or poor education.
The pattern of heights and depths made by the elements of a landscape. It can be seen on a map using contours or shading (hachuring), or in a cross section of an area.
A resource is renewable if it can be used repeatedly, given reasonable conservation measures; e.g. timber from forests where trees are planted to replace those cut down. Compare with non-renewable.
A resource which is available for future use.
An aspect of the environment which people find useful for satisfying their needs. It can be renewable or non-renewable.
A v-shaped drowned valley with tributaries.
A long thin lake occupying the floor of a U-shaped valley. There are several ribbon lakes in the Lake District.
A scale for measuring the energy of an earthquake, ranging from 1 to 10. 4+ is noticeable. 5+ does damage. 7+ is a disaster.
A section of the earth's crust which is bordered by faults, and has slipped downwards in relation to the surrounding areas. There is a spectacularly large rift valley running through east Africa.
A large stream of water flowing in a channel to the sea to a lake, or to another river. It starts in high ground where it has a steep course, and gradually levels out, always moving downwards and generally getting larger. The course of a river can be interrupted by waterfalls, and can contain rapids.
The steep outer bank of a meander. A cliff formed by the undercutting erosion of the bank by the fast-moving water going round the outside of the meander.
A smooth, rounded, hummocky rock surface worn by glaciation.
Igneous rocks are eroded and transported to form sediment. This in time becomes sedimentary rock, and when this is forced deep underground by the pressures of colliding tectonic plates, it is melted to form magma, which becomes igneous rock again.
The course taken between starting point and destination. Planners need to anticipate what route people are likely to follow, so that they can provide appropriate roads.
A rural area means an area that is part of the countryside.
Tiny grains of siliceous rock which are found on beaches, on riverbeds and in deserts, and which can be a large proportion of soil.
Sedimentary rock made of compressed sand. It can be very susceptible to erosion, easily crumbling back into individual sand grains.
An image transmitted from a satellite. Satellites continually scan the earth, measuring the brightness of light at different places. Some measure infra-red light, giving an indication of how hot a place is. The image can be coloured in by a computer, using false colours, so that buildings appear in one colour, vegetation in another, bare ground in a third and water in a fourth.
The grassland regions of Africa which lie between the hot deserts and the tropical rain forest.
An indication of what distance on a map represents a given distance on the ground.
The steep face of an escarpment.
Debris which accumulates under a crag which is subjected to weathering.
A landscape that is dominated by shrubs or stunted trees.
A major division of the year, with its own characteristic weather. The seasons in Britain are spring, summer, autumn and winter. Some countries have a rainy season and a dry season. See monsoon.
Temperature and rainfall in an area vary with the season. See the associated diagram for the seasonal pattern in the British isles.
The sector of the economy of a country concerned with manufacturing.
- See primary sector, secondary sector and tertiary sector.
sand or mud which has settled to the bottom of an expanse of water.
A sedimentary rock is one which has formed from layers of sediment.
A long sand dune, the ridge of sand running parallel to the prevailing wind.
A device for measuring the size of earthquakes. See Richter scale.
A town or village. Settlements can be founded as market towns, or at sites where routes meet, or where rivers can be crossed. In former times they were often placed at the tops of hills for easy defence, or next to a castle where the population could take refuge. Market towns usually form a hierarchy, with small towns close together serving small areas, and some larger towns providing more comprehensive services for larger areas.
A mountain range with a jagged outline; the name derives from the Spanish word for saw.
Containing silica (silicon dioxide); e.g. sand and quartz are siliceous.
Sediment deposited by a river in a channel or harbour.
A hole produced by the collapse of the roof of a cavern in a Karst area.
A hot, oppressive wind blowing from North Africa over the Mediterranean to parts of Southern Europe.
Sites for settlements are usually chosen because they are a meeting place for several routes or they are close to some resource. In the past it was also important to choose a site which could be easily defended. See industrial location for information on the choosing of industrial sites.
A close-grained metamorphic rock which is stratified in close-spaced planes. It is used for roofing.
Icy rain.
An unhealthy mixture of smoke and fog.
Precipitation which has crystallised into light white flakes.
Particles of rock mixed with organic material. Soil can be light (sandy) or heavy ( clay ) depending on the size of the rock particles. Loam is soil which has a large proportion of organic material, and is good for plants. Sandy soil usually drains well, but water can collect in clay soil, and it can be hard to break up.
In the direction contrary to north.
A renewable source of energy, from the sun.
A narrow bar of sand and/or shingle which sticks out into the sea or the mouth of a river.
An outcrop of rock.
A coastal feature created by the erosion of a headland. The sea wears away the connection between the headland and the mainland, eventually producing a natural arch. When the top of the arch collapses, a tall column of rock remains, called a stack.
A column of calcium carbonate hanging from the ceiling of a cavern. It is caused by drops of water, loaded with dissolved calcium carbonate, collecting at a low point in the ceiling and then evaporating, leaving the calcium carbonate behind.
A column of calcium carbonate built up from the floor of a cavern, where water drips from a stalactite.
Dry, uncultivated grassland in south-east Europe and in Asia.
Weather in which very strong winds occur, force 11 on the Beaufort scale, causing widespread damage (very rarely experienced).
A narrow band of sea separating two land areas; e.g. the Strait of Dover separates England from France.
A stratum is a layer in rock. The plural is strata.
A type of cloud which forms large dark globular or rolled masses but which does not bring rain.
The region of the atmosphere lying immediately above the troposphere.
A wide, extended sheet of low cloud. " Stratus " is a Latin word meaning stretched out, or layered.
A residential area in the outskirts of a town.
The second and warmest season of the year. In the Northern hemisphere, Midsummer day is the 24th of June.
A piece of wet, spongy ground; a marsh.
A fold in which strata dip down towards a common line.
A lake which forms in a cirque.
A measure of how hot or cold something (e.g. the air or the sea) is. It is measured with a thermometer.
See moraine.
Another word for landscape.
The sector of a country's economy concerned with providing services.
A device for measuring temperature. A maximum and minimum thermometer is useful for recording the range of variation in temperature.
The poor nations of Asia, Africa and South America.
The sound which accompanies lightning, usually seeming to follow it by several seconds because sound travels much more slowly than light.
A storm in which thunder and lightning occur.
See Tsunami.
The alternate rising ( flood tide ) and falling (ebb tide ) of the level of the sea, which happens twice each day, and is caused by the gravitational influence of the moon. A spring tide is a tide with a higher than usual range, which occurs when the sun is approximately in line with the earth and the moon so that its influence is added to that of the moon. A neap tide is one with a lower than usual range, which occurs when the direction of the sun is at a right angle to the direction of the moon, so that it is partially cancelling out the effect of the moon.
On mountains and in Arctic regions, the line beyond which there are no trees. The Arctic timberline separates coniferous forests from tundra.
A map in which regions or features may have approximately the right shape, but their size is altered to make it proportional to some feature such as population size.
A violent storm, with heavy rain, in which the wind rotates or constantly changes direction In the midwestern US tornados occur with a funnel shaped cloud extending toward the ground and doing considerable damage in a narrow path.
The large-scale moving of people to resorts for leisure and enjoyment or sightseeing. It can have a beneficial effect on the trade of an area, with a "tourist industry " being built up to supply the needs of tourists, but it can damage the character of an area; e.g. people flock to an area to see the coral reef and they accidentally damage it, or a pleasant village becomes a massive collection of hotels.
See international trade.
A regular wind in the area of the tropics, blowing towards the equator and from an easterly direction - they are deflected westwards by the easterly rotation of the earth.
The fixing of the positions of landmarks by measuring a single straight line on the ground and using it as a base line for triangles, with imaginary lines leading to the objects to be measured. The imaginary lines can be used as the base lines of new triangles, and so on. Knowing one side of a triangle and two angles, it is possible to work out the lengths of the other sides and the position of the third point.
The Tropics of Cancer and Capricorn mark the limits of the torrid zone, the area in which the sun can shine directly overhead. The Tropic of Cancer is north of the Equator, and the Tropic of Capricorn is to the south.
Associated with the tropic s; the sort of climate and ecosystem found between the tropics.
The lowest layer of the atmosphere, in which most weather phenomena occur. The temperature of the troposphere falls as height increases.
A very large, destructive wave produced by an undersea earthquake. Sometimes it is mistakenly called a tidal wave, but it has nothing to do with the tide. Tsunamis happen in parts of the Pacific, especially around the coast of Japan.
The barren subarctic plains of Northern America and Eurasia, north of the coniferous forests, from which they are separated by the timberline.
A violent cyclonic storm, especially one occurring in the China seas.
The counter-current to water breaking onshore as waves.
Associated in some way with a town. See urban decay, urban renewal, urban sprawl.
The process of deterioration of the infrastructure of parts of a city.
A scheme to solve the problems associated with urban decay - bad housing, inadequate transport and services - by slum clearance and the relocation of people and industry to less crowded areas, such as dormitory towns.
The growth in extent of an urban area which happens when improved transportation allows people to live further from their place of work.
A valley that has been deepened by a glacier, so that a cross section of it looks like the letter U.
An elongated hollow between hills, carved by a river or a glacier. Valley settlement takes place in areas where the valleys form natural routes for communication. This happened especially in South Wales, with the mines and towns in low areas, with upland farms in between. See also dry valley, U-shaped valley, V-shaped valley, wadi.
Igneous rock produced by the cooling of lava, that is, magma that reaches the earth's surface. Basalt and pumice are examples of volcanic rock. Compare with igneous rock, which may have cooled below the earth's surface.
An outlet for lava (that is, magma that reaches the earth's surface). It generally forms a cone, the steepness of which depends on the type of the lava. Acidic lava flows very slowly and produces a steep cone. Basic lava flows quickly and produces a very gentle slope.
A dry valley in a desert. It is carved by torrents during rare flash floods.
One of the causes of widescale migrations. People escaping from a war are called refugees.
See front, depression.
The level, in porous rock, below which the ground is saturated.
A point in the course of a river where it plunges abruptly from one height to another.
The boundary between two river basins. Rain landing on one side of the watershed supplies the first river, and rain landing on the other side supplies the second river.
A moving ridge of water between two troughs. When it reaches the shore, it can break up into a violent, clashing mass of water which wears away at cliffs and headlands (see erosion ), or it can be responsible for transporting material along the beach (see longshore drift ).
A gently sloping beach eroded by the sea along a coastline.
The day-to-day conditions of cloud cover, precipitation, temperature, humidity and other atmospheric effects such as thunder and lightning. Winds are the biggest influence on weather. When two air masses of different temperatures and pressures meet, a front is produced. Fronts are associated with rain and with changeable weather. The study of weather is called meteorology, and the office which provides weather forecasts is the meteorological office. The movement of air at a front can be chaotic, and this makes prediction difficult, so that the meteorological office cannot always give accurate forecasts even though it uses very powerful computers and sophisticated programs.
A map of an area giving details of the weather recorded earlier, or forecast.
The breakdown of rocks in situ, caused by exposure e.g to frost. Compare with erosion, in which the broken-down materials are transported elsewhere.
A circular eddy in the sea formed by the coming together of two currents.
See tornado.
A movement of air. It is measured using the Beaufort scale. The direction is measured using a wind vane or a wind sock. Wind is caused by convection, and is modified by the relief of the ground.
A cone-shaped sleeve of cloth attached to a pole, to show the wind direction.
An instrument used to indicate wind direction; also called a weathervane or weathercock.
The fourth and coldest season of the year.
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