Geography

Chapter 1:

• Study and description of the Earth's environment
• Categorised into physical and human environments

Physical Environment

• Physical features and processes that occur naturally
• exist nature, not modified by humans
• eg Mountains, rivers and natural vegetation
• Consists of Air, Land, Water and Living Environment (interrelated)

Human environment

• Physical environment changed by human activities
• Natural materials used are natural resources
• Change and modify physical environment using technology, skills, and knowledge

Physical-Human relationship

• The way physical environment affects how humans live
• How people affect the environment through human activites

Chapter 2:

Earth

• third planet from the Sun
• Fifth largest planet
• Diameter of 12, 756km
• Rotation-one day
• Spins west to east on axis (23.5)
• Revolution-365.25

Earth's seasons

• Revolution and the tilt of the Earth determine the amount of sunlight and heat the surface of the Earth gets from the Sun
• Results in four seasons
• Northern Hemisphere: June-Summer, tilted mostly towards sun (note, southern, opposite)

Fragile Earth

• Need to do 3Rs
• Only planet we can live in

Chapter 3:

Environment through photographs:
Photographs:

• visual record of information
• form accurate image of the world
• show actual features

They are: 

1. sources of information
2. records of change
3. tool to study environment

Different types of photographs:

• Landscape, taken at ground level

Show big picture of area, show main features and other less important details

• Aerial, taken from a height

Show a larger area, do not show details of features. Useful for estimating size of a feature/area and studying the layout of a settlement and its surroundings

• Satellite image, taken by instruments on satellite and recorded in 'real time'
• used to capture a very large area of the earth's surface
• used to study changes in the environment and weather

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Maps

• Pictures of Earth surface
• Topographical or thematic

Uses of maps:

• Sources of information
• Tool used for planning 
• Records of change

Latitudes:

• Tropic of cancer (23.5N)
• Arctic circle (66.5N)

Travel west across IDL: date move forward by a day

Greenwich/Prime Meridian (Longitude)

Chapter 4:

Chapter 5: 
Landforms and rocks:

• Created by processes beneath and on Earth's surface
• Examples of landforms: mountains, valleys.
• Examples of rocks: limestone, granite

Rivers, lakes, oceans:

• About 75% of Earth's surface
• Rivers = streams of water that flow from high to low ground
• Example: Waterfall.

Weather and climate:

• Earth surrounded by atmosphere
• Weather => condition of atmosphere over a short period of time
• Climate => Weather pattern over long period of time
• Temperature + rainfall + wind affect weather and climate.

Natural vegetation:

• Plants that grow naturally

Chapter 5: Interpreting Topographical maps

• shows details of physical & human features in an area
• grid lines = imaginary vertical/horizontal lines

eastings = ----

northings = |

Contours:

• lines that are close represent sleep slopes
• lines that are far apart represent gentle slopes
• contour lines absent/very far, represents almost flat land

Valleys:

• contours forming inverted 'V'
• Streams/rivers found there are drawn as blue lines

Plateau:

• Upland area
• Steep slopes and flat summit

Ridge:

• Linear or elongated upland area

Chapter 6: Landforms of the earth
Core of the earth:

• at the centre of the earth
• temperatures up to 5000 degrees
• mostly solid in inner core (due to intense pressure exerted on the centre by outer layers of earth)
• made of iron + nickel
• Outer core -- liquid state

Mantle:

• Layer surrounding core
• 2900km in thickness
• Temperatures of more than 2000 degrees
• Often in semi-liquid state 

Crust:

• Outermost layer of earth's surface
• In solid state
• Thinnest layer
• Thickness vary from 6 to 70km
• made of plates

Why do plates move?

• Plates move due to convection currents in the mantle
• Magma is heated by the core and rises towards the crust
• As it rises, it cools, becoming denser and heavier causing it to fall back/sink down towards the core. 
• The cycle repeats itself, forming convection currents. 

Types of plate movement:

1. Divergent plate movement (constructive)
2. Convergent plate movement (destructive)
3. Transform plate movement (conservative)

Divergent plate movement:

• As the two plates move apart, magma rises to the surface, cools and solidifies forming a long chain of mountains on the ocean floor called oceanic ridges.
• The movement of two oceanic plates away from each other causes magma moving up, cooling and solidifying resulting in the formation of a new oceanic crust. This is also known as sea-floor spreading. 

Example: Mid-Atlantic ridge beneath the atlantic ocean

Convergent plate movement:

• When two plates move towards each other, the denser oceanic plate descends or subducts under the continental plate. 
• A destructive plate boundary is found here as part of the oceanic plate is being destroyed. 

When the thinner and denser oceanic plate converges with a thicker and lighter continental plate, the oceanic plate will slide under the continental plate. This is known as subduction. Movement may be violent and cause earthquakes. When the subducted plates are melted due to intense pressure, the magma will force through the vents and form volcanoes. 

When two continental plates meet each other, one may be pushed under the other for a short distance. But there is no subduction as both are light and buoyant. Instead, they produce distorted fold mountains. 

Example: Himalayas. 

Faulting or earthquake may be present due to great amount of pressure and friction. But there is no volcanic activity as there is no subduction. 

When two oceanic plates meet, one plate sinks beneath the other due to different density. An oceanic trench/ undersea volcano is formed. 

Example: Marianas Trench in Pacific Ocean. 

Transform plate movement: occurs when two plates slide past each other along a fault. Plates grind against each other as they move in opposite directions. This causes earthquakes. This is known as a conservative plate boundary as no land here is created or destroyed and no volcanoes or fold mountains is formed. 

Example: San Andreas fault. 

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What is vulcanicity? 

• Plate movements along boundaries and high temperatures increase pressure in the mantle. 
• Magma forces its way upwards through vents to the Earth's crust. 
• Magma pours onto the Earth's surface as lava
• The process by which magma and other materials reaches Earth's surface is called volcanicity. 
• Lava cools and solidifies around the vent 
• Lava accumulation results in the formation of a volcano. 

Types of volcanoes:

Active volcanoes like Mount St Helens. 

Dormant volcanoes like Mount Rainer.

Extinct volcanoes like Mount Kilimanjaro. 

Plateaux: Formed when a large quantity of magma escapes from a fault in the Earth's crust and spreads over a wide area. Layers of hardened lava form a plateau.

Risk of living near volcanoes:

1. Destruction: Lost of property, settlements.... etc
2. Pollution: Volcanic ash pollute environment 
3. Health hazard: Damage respiratory system
4. Loss of lives: people killed by ash
5. Earthquakes and Tsunamis: destroyed settlements and loss of lives. 

Benefits:

• Fertile soil due to weathered volcanic materials
• Precious stone and minerals formed due to vulcanicity
• Tourism

Chapter 7: Coasts

Coast:

• The zone where the land meets and interacts with the sea. 
• Ever changing landscape shaped by erosion and deposition

Shore: Land between high and low water marks

Waves: Up and down movements of the water surface produced by winds blowing over the sea or ocean. 

Wind energy:

• Air moves from high pressure areas to low pressure areas
• The higher the difference in pressure, the greater the wind speed hence higher wave energy

Duration of wind:

• The longer the wind blows, the larger the waves

Fetch:

• Refers to the distance traveled by winds over open seas
• The greater the fetch, the higher the wave energy

Wave moments:

1. Swash -- forward movement of waves, carries materials up the shore
2. Backwash -- water that flow back to sea due to gravity, carries materials back toward the sea.

Constructive waves:

• Low energy waves
• Occurs on gentle-sloping shores
• Stronger swash and weaker backwash 
• Deposits materials on the shore more than it erodes. 

Destructive waves:

• High energy waves
• Occurs on steep-sloping shores
• Stronger backwash and weaker swash
• Erodes materials from the shore more than it deposits

Coastal Erosion - C.A.S.H

Corrasion

As waves crash onto the coast, these materials are thrown against the coast, gradually eroding the coast. 

Attrition

As the materials collide, the impact causes the materials to break into smaller pieces eventually. 

Solution

The water reacts with the minerals in the rocks and dissolve them. 

Hydraulic action

As the waves pound the coast, the air within these cracks is compressed. When the waves recede, the compressed air suddenly expands. Over time the repeated expansion and compression of air cause the cracks to widen and the rock structure along the coast to weaken. 

Factors affecting coastal erosion

1. Types of waves (when waves have higher energy, higher wind speed, longer duration of wind, longer fetch)
2. Position of coast (anything that protects it from erosion?)
3. Composition of rocks (lines with more lines of weaknesses, consist of softer rocks or more soluble rock minerals will be eroded faster)

Coastal landforms by Erosion:

 1. Wave-cut platform.

• Hydraulic action and abrasion attack lines of weakness on the rock surface forming a notch overtime. 
• As erosion continues, the notch will further develop into a seacave.
• Further erosion will cause the roof over the seacave to collapse, forming a steep rock face known as a cliff
• As the process repeats, the cliff will retreat further inland, leaving a gently-sloping platform known as a wave-cut platform. 

 2. Headlands and bays

• Formed from coasts with alternate strips of resistant and less resistant rocks. 
• Less resistant rocks will be eroded faster than more resistant rocks. 
• When the softer rocks have been eroded away, the land curves inwards to form bays
• The remaining hard rocks that remain behind extends out to sea and are known as headlands. 

 3. Arches, stacks & Stumps

• Waves erode along a line of weakness on the headland to form a notch. 
• The notch is further eroded to form a cave. 
• The cave is continually eroded until a hole is cut through the headland and an arch is formed. 
• Further erosion of the arch causes it to collapse, leaving a stack which is left standing in the sea. Overtime, the stack is worn out by erosion, to form a stump.  

Chapter 8:

• Weather: condition of a place over a short period of time
• Climate: weather pattern of a place over a long period of time

Elements of weather and climate: Temperature, rainfall and wind

Temperature: degree of hotness or coldness of the air, varies throughout the day, hotter at the equator, colder as you go to higher grounds. Measured by thermometer.

Stevenson's screen: 

• wooden box with louvers (for air circulation)
• roof made of double layers to protect instrument from direct rays of the sun
• painted white to reflect the heat from the sun
• box stands about 1 meter above the ground so heat radiating from ground would not affect reading of thermometer

Rainfall: amount of rain an area receives over a period of time

Measured by rain gauge, which is made up of an outer casing, a copper cylinder, a glass bottle, a funnel and a separate measuring cylinder. Rain gauge measures rainfall in millimeters or centimeters. 

Wind: movement of air from one place to another, due to difference in air pressure caused by heat.
Inductive fieldwork studies:

Observation -> Data collection -> Data analysis -> detect pattern -> tentative hypothesis -> derive theory -> repeat

Deductive fieldwork studies:

Hypothesis -> Data collection -> Data analysis  -> Confirmation of hypothesis

Hypothesis = relationship between 2 variables

Temperature variations:

Poles experiences lower temperature -> solar radiation spread over large area, travel great distances, less intense.

Sun's rays travel different distances, strike Earth's surface at different angles.

Normal lapse rate -> temperature falls by 6.5 degrees for every 1000 metres increase.

Earth's surface absorb heat from Sun directly (warmer)

Thin air, unable to absorb heat as effectively, smaller concentration of gases to trap heat.

Micro-climate: study of climate over a small area.

Factors affecting temp. within places:
Increase temp:

• surface of buildings (type of materia: reflective vs non-reflective)
• colour of buildings
• presence of buildings (absorb heat - metal slabs, concrete, stop wind)
• lack of vegetation (vegetation reduce amount of solar radiation from reaching ground directly.)
• lack of trees (trees lose water to surroundings, cool temp. prevents heat from reaching ground directly)
• absence of clouds (more heat during daytime, less heat during night time)
• dust particles (dust particles trap heat)
• car exhaust (gases trap heat)

Sea breeze:

-land warmer than sea during day. Air heated, forming low pressure area

-sea does not heat up as fast as land. Air over it is cooler, forming high pressure area. 

-Air from high pressure area to low pressure area -> forms sea breeze from sea to land. 

Land breeze:

-land cools down faster, high pressure area formed. 

-sea does not cool down fast, low pressure area formed. 

-high to low pressure area, form land breeze, from land to sea. 

Land and sea breeze diagram: http://bentsci.edublogs.org/files/2009/11/sea-land-breeze.gif

buildings block sunlight. 

more cloud cover - smaller difference in day~night temp. 

less cloud cover - larger difference in day~night temp. 

Types of climate
Tropical equatorial:

10 N to 10 S

High mean annual temp.  (reason?)

Uniform temp. (reason?)

Rainfall above 2000 mm (convectional rain, monsoon gives additional rainfall)

Tropical monsoon: 

10 N ~ 25 N

10 S ~ 25 S

high mean annual temp. (lower than tropical equatorial, why?)

annual temp range is 6 degrees. 

total annual rainfall about 1500~1900mm. 

distinct wet&dry seasons. 

affected by monsoon (NE from nov ~ march, SW from june ~ sept)

Cool temperate climate:

35N~70N

35S~70S

four seasons

different amounts of sunlight, temp. vary greatly (about 25 degrees)

coastal - less extreme. inland - more extreme. 

low mean annual temp of <10 degrees.="" p="">

precipitation - rain & snow (300~900mm), not uniform.

Consequences of global warming:
changes in weather conditions: prolonged droughts in dry regions, frequent heat waves, severe flooding in wet regions

spread of diseases: rising temp, heavy rainfall allows mosquitoes to thrive, spread of diseases.
heat waves => people die of dehydration or heat stroke.

Geography: Managing Earth's scarce resource: Water
Why is there a water constraint?

Demand - population rising, agriculture, industrial and changes in lifestyle.
Supply - Limited water supply, people pollute fresh water, uneven distribution.

How do we respond to the rising demand of water?
Increase price of water to encourage saving water. It promotes more efficient use, and questions of affordability arise. (public education, save water campaigns)

Increase supply of water - increase catchment areas, use technology (desalinate and recycle water), international agreements.

Increasing catchment areas can conserve forests and it keeps cost of water treatment down. But more land is set aside for water catchment, and it is not effective in dry seasons.

Technology takes large amount of energy and it is very expensive.

Case study of water supply:

S'pore's rivers does not have enough fresh water. It has occasional dry spells

Catchment area is cleared for development and housing.

Demand for water is increasing due to population and industries growing, changes in lifestyle

Water is needed for household, industrial and business activities. It affects people's health and increases the country's vulnerability.

We overcome water constraint with the 4 national taps.

Policies and campaigns to conserve water supply - public education, "save water" campaign, water conservation tax.

Population

Factors affecting world population growth rate:

• better medical and health care
• improvements to hygiene
• increase in food supply 
• advances in technology

Factors influencing population distribution:

Physical environment:

• relief
• climate (people avoid areas with extreme climate)
• soils (people live in areas with fertile soil)
• vegetation cover 

Economic factors:

• mineral and energy resource (attract developers and settlers)
• well-developed transportation and communication facilities (increase accessibility, encourage trade and development)

Improvement in technology can enable people to convert environments which were previously unsuitable for living into suitable living environments. 

Population density: number of people living in a unit area of land. 

Importance of population pyramids:

• Useful for future planning

Broad-based population signifies a rapidly increasing population. Hence, it is necessary to:

• increase food population
• build more houses and schools
• plan for more job opportunities
• implement birth control programme. 

Population Studies

Causes for high population growth (high birth rate and low death rate):

Low death rate (factors):

• improvement in medical facilities, health care services, housing, hygiene, clean water supply, sanitation, nutrition
• better medical care improves survival rate of babies, reduce infant mortality rate
• less prone to falling sick. 

High birth rate

• social factor: lack of family planning, enter into early marriages. 
• cultural and religious factor: preference for sons
• economic factor: need for farm labour
• political factor: government can launch policies to control birth rate. 

Consequences of high population growth:

• demand for resources increase. 
• higher demand for housing- more make-shift houses
• need to provide enough education 
• intense competition for limited amount of jobs
• environmental problems arise when there is a lack of proper waste disposal

Actions to control high rate of population growth:

• easily accessible family planning services
• education and inculcation of proper family planning methods
• incentives and penalties

China's "one-child" policy:

Reasons to curb massive population growth:

• more than 50% of GNP used to support huge population
• huge population strains food supplies, health and medical care, transport, housing, education and employment
• causes congestion in urban centres

Measures to reduce high birth rate:

• widely publicized policy through mass media
• incentives: monetary awards, priority housing and access to health care services
• couples who violate policy were fined
• single-child given priority in education & housing
• free contraceptives
• abortion and sterilization made legal. 

Low rate of population growth (low birth rate and death rate):

Low death rate:

• high SoL, less prone to diseases associated with unhygienic living conditions
• higher levels of income, can afford better nutrition
• better medical and health care can prolong life expentancy

Low birth rate:

• more people remain single
• more people entering late marriages
• people prefer smaller families due to increased SoL

Consequences of Low population growth:

• face ageing population (burden on working population increase)
• lead to higher taxes on each working person to fund public amenities and projects
• smaller talent pool to lead and serve country

Actions to manage low rate of population growth:

• encourage marriage and childbearing in forms of tax rebate
• build special facilities for elderly (specilized hospitals, day care centre)
• exercise classes at community centres
• retirement age raised 
• encourage financial planning to ensure enough financial resources. 

Case study: Japan's ageing population:

Since 1990, as industrial development accelerated, the population increased at a rapid rate. However, pop. growth declined since then. There was a postwar baby boom after WW2. An improvement of medical services causes decline in death rate. Low birth rate due to successful family planning programmes and legalizing of abortion. 

Singapore's ageing population:

• government embarked on campaigns to encourage family life
• provides monetary incentives (tax subsidies) to couples with more children
• more open to immigration
• higher priority in admission to primary schools for third child
• housing priority for married S'poreans who have aged dependents living with them. 
• studio-apartment for elderly people.