H

Question 0

Hadean

Answer 0

An eon of geologic time lasting from 4600m to 3800m years ago.

Question 1

Habitat

Answer 1

Particular environment in which any one species of plant or animal is able to live.

Question 2

Hadley Cell

Answer 2

That portion of the tricellular model of air circulation where air rises at the equator due to convection, spreads in the upper troposphere and then sinks over the tropics before returning to the equator.

Question 3

Hail

Answer 3

Balls of ice a few millimeters in diameter which fall as precipitation. The balls form when water in clouds is lifted high enough to freeze. The droplets may fall a little and accumulate more water before further uplift cause more freezing and thus they grow. Eventually, their mass is enough to allow them to fall through the uplift. Ground temperatures must be low to prevent melting before they reach the surface.

Question 4

Halophyte

Answer 4

A plant that is able to tolerate environments with a high level of salt. Found usually in coastal areas or arid areas where potential evapotranspiration exceeds precipitation for large parts of the year.

Question 5

Halosere

Answer 5

Plant succession in a saline environment e.g. estuary, salt marsh.

Question 6

Hamada

Answer 6

Flat, exposed bedrock in an arid area.

Question 7

Hamlet

Answer 7

Small settlement with a purely residential function. Usually fewer than 100 inhabitants and no services except perhaps a post box.

Question 8

Harris-Ullman model

Answer 8

Model of urban land-use based on multiple nuclei i.e. more than one centre. Used to explain land-use in larger urban areas such as conurbations where there are many locales exhibiting features of CBDs as smaller settlements have been enveloped by the growth of the main city or have coalesced into it with their own growth.

Question 9

Hanging valley

Answer 9

A small glacial valley entering a larger one someway up the side of the latter. Created by the differential in erosion between the different sized glaciers that formed the respective valleys.

Question 10

Hardpan

Answer 10

A thin crust of material within a soil as a result of the illuviation of iron and/or aluminium from layers above or the precipitation of calcium carbonates which cement sands together.

Question 11

Hazard

Answer 11

An event or condition which threatens people and property. May be natural e.g. earthquake, blizzard, or human e.g. industrial waste, HIV, or a combination e.g. drought, famine.

Question 12

HDI

Answer 12

See human development index.

Question 13

Headland

Answer 13

At the coast, land jutting out further into the sea and separating bays. See also discordant coast.

Question 14

Headward erosion

Answer 14

The lengthening of a young valley or gully by water erosion at the head of its valley.

Question 15

Headwaters

Answer 15

The uppermost portion of a river course close to the source.

Question 16

Heat budget

Answer 16

See energy budget.

Question 17

Heat equator

Answer 17

The tilt of the earth means that during an orbit cycle the line of latitude receiving the most concentrated insolation migrates between the tropics. On 21st June, the sun is most directly above the Tropic of Cancer and, on 22nd December, most directly above the Tropic of Capricorn.

Question 18

Heat island

Answer 18

The warm air found around and above an urban area, distinct from the air temperature above the surrounding rural land.

Question 19

Heathland

Answer 19

An environment of grass and shrubs which develops in nutrient deficient parts of temperate areas. In Europe, they are often the result of forest clearances but are now deliberately maintained for rough grazing and shooting estates.

Question 20

Heavy industry

Answer 20

Those secondary industries using bulk raw materials for both energy (e.g. coal) and production (e.g. ores). They often manufacture products for other secondary industries.

Question 21

Helical (or helicoidal) flow

Answer 21

The spiraling flow of water in meandering channels caused by the deflection of flow as water hits the bending banks.

Question 22

Hemisphere

Answer 22

Literally half a sphere. In geography, the division of the earth either into north and south by the equator, or into east and west by any one line of longitude.

Question 23

HEP

Answer 23

See hydro-electric power.

Question 24

Herbicide

Answer 24

A chemical used to control / prevent weed growth in arable farming.

Question 25

Herbivore

Answer 25

Any organism which feeds exclusively on plants (producers).

Question 26

Heritage

Answer 26

Literally anything that is passed one from one generation to the next. Commonly applied to the buildings and rural landscape of a nation and especially in relation to those that are considered worth keeping for the future.

Question 27

Hierarchy

Answer 27

Organisation by class of importance, status or authority. Usually a negative correlation between class and number of members i.e. the higher the class the lower the number of members of that class.

Question 28

High-order good / service

Answer 28

One which is high in value and long-lasting and therefore generally bought infrequently e.g. car, accountant.

Question 29

High tide

Answer 29

The highest point to which the sea rises against the land in its daily vertical movement.

Question 30

High-yield variety

Answer 30

Grain crop which has been selectively bred to produce seeds which produce far more than otherwise.

Question 31

Hinterland (also periphery)

Answer 31

The area surrounding a core settlement from which the settlement gains resources.

Question 32

Histogram

Answer 32

A bar chart where the vertical (y) axis is frequency and the horizontal (x) axis is the classes / values of data that have been measured for frequency.

Question 33

HIV

Answer 33

See human immunodeficiency virus.

Question 34

Hi-tech industry

Answer 34

Those industries that have developed since the late 20th century in areas such as electronics, IT, pharmaceuticals etc. They have a high component of research and development and are at the forefront of technological innovation.

Question 35

Hjulstrّm curve

Answer 35

A graph showing critical stream velocities for the erosion, transport and deposition of different sizes of load.

Question 36

Holocene

Answer 36

The current geological period, currently about 10,000 years long.

Question 37

Honeypot

Answer 37

A place of special interest, especially with reference to tourist visitors. Honeypots may be developed deliberately as a way to concentrate tourists into manageable areas and reduce pressures on surrounding fragile environments.

Question 38

Horizon

Answer 38

Two uses:

1. The line where the visible surface appears to ‘meet’ the sky.
2. In a soil, a distinct layer having unique characteristics.

Question 39

Horizontal integration

Answer 39

The merging of firms at the same stage of production.

Question 40

Horizontal transfer

Answer 40

Transfer or transmission of energy from lower latitudes to higher latitudes. Two kinds: in the air by the movement of air (wind). Highly complex and not fully understood. Transfers take place between the cells of general circulation (see tricellular model) but the exact mechanisms are not clear. in the ocean by the existence of warm and cold currents. Warm currents move energy in surface waters from low to high latitudes, returning as cold currents at depth.

Question 41

Horst

Answer 41

A raised block of land bordered by fault lines.

Question 42

Horticulture

Answer 42

See market gardening.

Question 43

Hot spots

Answer 43

A localized area of extreme heat. On earth, they refer to places where an upward plume of magma comes close to the surface in a shield area such as in Hawaii. The term may also be used to refer to areas of the surface of the sun giving off unusually large amounts of energy.

Question 44

Housing association

Answer 44

In the UK, non-profit organizations offering a third ‘way’ outside of the traditional housing provision of the private sector and local government. Originally set up to provide rental accommodation they now also offer a way for people to become owners. They still focus on helping lower income groups find appropriate accommodation.

Question 45

Hoyt, Homer

Answer 45

Architect of the sector model of urban land-use.

Question 46

Human Development Index

Answer 46

An attempt to make ‘fairer’ but still statistical measurements of development that became popular at the UN in the 1990s. Assigned value between 0 and 1 according to ranking position for each of the factors of purchasing power of income, literacy rate and longevity. Theoretical maximum of 3 was index 1. Criticized for measuring ranking rather than absolute idea of development, plus probably too biased in favour of wealth-dependent factors.

Question 47

Human immunodeficiency virus

Answer 47

A virus which forms DNA while replicating its RNA leading to the development of AIDS.

Question 48

Humidity

Answer 48

The water vapour content of the atmosphere. Two main measures are absolute humidity and relative humidity. Humidity is controlled by air temperature (the higher the temperature the more water vapour can be held) and water availability for evapotranspiration.

Question 49

Humus

Answer 49

The decomposed organic element of the soil. Identified both as an independent horizon in some soils, or in the clay-humus complex. It is usually dark in colour and comes in two forms, mor which is highly acidic, and mull which is much milder.

Question 50

Hurricane

Answer 50

Term for a tropical cyclone forming in the Atlantic or Caribbean. They usually pose a hazard to the Caribbean islands and south-eastern USA.

Question 51

Hybrid

Answer 51

A plant with certain characteristics achieved by cross building different plants for their particular qualities.

Question 52

Hydration

Answer 52

A process of chemical weathering. Some minerals take up water and form weaker compounds e.g. anhydrite + water = gypsum which more readily dissolves. The expansion can also put physical stress on the rock.

Question 53

Hydraulic action

Answer 53

Literally due to the action of water. In geography, a process of erosion whereby flowing water moves unconsolidated material due to forces of drag.

Question 54

Hydraulic radius

Answer 54

Stream efficiency measured by dividing cross-sectional area of a stream by the wetted perimeter. A higher ratio indicates greater efficiency as area will be greater compared to wetted perimeter and it is the latter which reduces efficiency through friction.

Question 55

Hydro-electric power (HEP)

Answer 55

Electricity produced through the use of moving water to turn turbines and drive generators. On a small scale HEP stations can be placed to take advantage of natural situations such as waterfalls, but usually they are built on a large scale by damming suitable valleys to create a reservoir. The water in the reservoir thus gains potential gravitational energy. When allowed to fall through the dam to the turbines this energy is converted to kinetic energy which drives the turbines. Require huge initial capital outlay but then produce highly efficient and cheap electricity. Also criticized for flooding farming land and villages thus displacing people and changing the environment and the river regime downstream of the dam. Nevertheless, a non-polluting and renewable form of energy. Provides a small percentage of world energy but highly important in some countries having ideal geological, meteorological and political conditions e.g. Norway and Sweden.

Question 56

Hydrograph

Answer 56

A graph which combines a bar chart of precipitation in a particular event with a line graph of discharge for a particular river channel in the catchment area of that event and thus the reaction of the channel to the precipitation.

Question 57

Hydrological cycle

Answer 57

The circulation of water around the world between stores by various transfers. At a simple level: water evaporates from the ocean, moves with the wind, condenses into clouds, precipitates and returns to the ocean via a river.

Question 58

Hydrolysis

Answer 58

Process of chemical weathering whereby a chemical reaction takes place between ions in a mineral and either the H+ or OH- ions in the water.

Question 59

Hydrophyte

Answer 59

Any plant which has adapted to moist environments.

Question 60

Hydrosere

Answer 60

A freshwater environment in which primary plant succession takes place.

Question 61

Hydrosphere

Answer 61

The earth’s water habitats: oceans & seas, lakes & rivers, ice and underground water.

Question 62

Hygroscopic

Answer 62

A substance that attracts water.

Question 63

Hygroscopic water

Answer 63

That water in the soil which exists as a microscopic level as a layer around particle of clay. It is held by electrical attraction and is unable to leave the soil.

Question 64

Hypersaline

Answer 64

Literally with high salt content. Hypersaline lakes such as the Dead Sea have a much higher salt content than ‘normal’ sea water.

Question 65

Hypothesis

Answer 65

The proposition of a relationship between variables which can then be tested and either rejected or accepted.

Question 66

HYV

Answer 66

See high yielding variety.