Saturday, August 05, 2006
GEOG - Population
Birth rate
No. of births x 1000 / Total population
<20 - low
20-30 - medium
>30 - high
Death rate
No. of death x 1000 / Total population
<10 - very low
10-15 - low
15-20 - high
>20 - very high
Natural increase - natural growth in population resulting from an excuess of births over deaths
Natural decrease - natural decrease in population when death rate exceeds the birth rate
Net migration - immigrants(entering country) minus emigrants (leaving country) [either positive or negative]
Zero population growth - birth rate = death rate
Population Explosion - large and rapid increase in population
Life expectancy - length of time a person born in a given area can expect to live
Infant mortality - number of babies who die before reaching one year old
No. of infant death x 1000 / No. of babies born alive
Total fertility rate - average number of children each woman would bear in her child bearing years
Replacemet fertility level - level of fertility at which a given population is replacing itself
Dependent population - population that depends on the working population to support economically (children - young dependents, the aged - old dependents)
[dependents x 100 / working age adults = number of dependents per 100 working age adults]
Sex Ratio - number of males to every 1oo females (high in areas with more male employing activities)
No. of births x 1000 / Total population
<20 - low
20-30 - medium
>30 - high
Death rate
No. of death x 1000 / Total population
<10 - very low
10-15 - low
15-20 - high
>20 - very high
Natural increase - natural growth in population resulting from an excuess of births over deaths
Natural decrease - natural decrease in population when death rate exceeds the birth rate
Net migration - immigrants(entering country) minus emigrants (leaving country) [either positive or negative]
Zero population growth - birth rate = death rate
Population Explosion - large and rapid increase in population
Life expectancy - length of time a person born in a given area can expect to live
Infant mortality - number of babies who die before reaching one year old
No. of infant death x 1000 / No. of babies born alive
Total fertility rate - average number of children each woman would bear in her child bearing years
Replacemet fertility level - level of fertility at which a given population is replacing itself
Dependent population - population that depends on the working population to support economically (children - young dependents, the aged - old dependents)
[dependents x 100 / working age adults = number of dependents per 100 working age adults]
Sex Ratio - number of males to every 1oo females (high in areas with more male employing activities)
Monday, October 03, 2005
BIOLOGY: diagram of villus
this is for the benefit of monkey who was asking me about the villus/lacteal/lymph on sunday. haha. JIAYOU! (:
Friday, September 30, 2005
HCL -- bao zhang bao dao/yi lun wen
Three types of bao zhang bao dao:
- yi ban xian xiang/she hui xian xiang
- ge an
- zheng ce
What to write for yi ban xian xiang:
1) state your views
2) Analyse the reason for the phenomenon
3) ‘reflect’: consequences, effects etc.
4) suggest possible solutions
5) conclusion
What to write for ge an:
1. state views
2. analyse problem/root of the problem (note: remember to state that it is a possibility, and not assume that it IS really the root of the problem)
3. Construct a stand
4. Bring it up to a higher level (e.g. how would a suicide over lousy grades affect other students in Singapore? Suicide over lousy grades: is it because the society is giving us too much stress? That kind of rubbish)
5. Ways to counter the problem
6. conclusion
What to write for zheng ce:
1. state views
2. State stand
3. analyse good and bad points about the policy
4. predict the results of the policy ie what effect would it have on the affected people?
5. Conclusion: reiterate stand
yi lun shou fa:
- analogy
- examples
- quotes
- contrast
please remember to memorise your ge shi! Losing marks over wrong format isn’t worth it! Hahaha good luck guys!
-- hh! (:
- yi ban xian xiang/she hui xian xiang
- ge an
- zheng ce
What to write for yi ban xian xiang:
1) state your views
2) Analyse the reason for the phenomenon
3) ‘reflect’: consequences, effects etc.
4) suggest possible solutions
5) conclusion
What to write for ge an:
1. state views
2. analyse problem/root of the problem (note: remember to state that it is a possibility, and not assume that it IS really the root of the problem)
3. Construct a stand
4. Bring it up to a higher level (e.g. how would a suicide over lousy grades affect other students in Singapore? Suicide over lousy grades: is it because the society is giving us too much stress? That kind of rubbish)
5. Ways to counter the problem
6. conclusion
What to write for zheng ce:
1. state views
2. State stand
3. analyse good and bad points about the policy
4. predict the results of the policy ie what effect would it have on the affected people?
5. Conclusion: reiterate stand
yi lun shou fa:
- analogy
- examples
- quotes
- contrast
please remember to memorise your ge shi! Losing marks over wrong format isn’t worth it! Hahaha good luck guys!
-- hh! (:
Thursday, September 29, 2005
CHEMISTRY: structure of macromolecules
DIAMOND and GRAPHITE
this is something like a continuation I guess. more in-depth (:
DIAMOND
1. tetrahedral structure
-each carbon atom is covalently bonded to 4 other carbon atoms
2. hard (due to covalent bonds)
3. high melting point (3550 degC) and boiling point (4827 degC)
-a lot of heat energy is required to break the covalent bonds
4. does not conduct electricity
-carbon has 4 valence electrons and since it is tetrahedral all 4 electrons are used in bonding, so there are no mobile charged particles
5. an allotrope of carbon
-different forms of the same element
USES OF DIAMOND
1. as tips of drills to drill through the ground/seabed (due to hardness)
2. grinding (hardness again)
3. polishing
GRAPHITE
1. made of flat layers of carbon atoms. layers have weak van der waal's forces between them. each carbon atom is covalently bonded to three others.
2. "soft” and slippery
- the layers have weak van der waal's forces between them, and slide off easily, giving the impression that it is soft.
3. high melting point (3652-3697 degC) and boiling point (4200 degC)
- covalent bonds between carbon atoms within each layer need a lot of heat energy to break
4. can conduct electricity
- unlike diamond each atom is bonded to three others so there is one extra delocalised electron that is free and mobile and thus graphite can conduct electricity because there are charged particles
5. an allotrope of carbon
- in fact, graphite is the stablest allotrope of carbon, even diamond will become graphite. you can like observe it (but WAIT LONG LONG!)
USES OF GRAPHITE
1. lubricant (soft and slippery to reduce friction, and can be used at high temperatures as well due to high MP and BP)
2. pencil lead (soft, layers slide off onto paper and stick there)
3. inert electrode for electrophoresis (good conductor of electricity)
this is something like a continuation I guess. more in-depth (:
DIAMOND
1. tetrahedral structure
-each carbon atom is covalently bonded to 4 other carbon atoms
2. hard (due to covalent bonds)
3. high melting point (3550 degC) and boiling point (4827 degC)
-a lot of heat energy is required to break the covalent bonds
4. does not conduct electricity
-carbon has 4 valence electrons and since it is tetrahedral all 4 electrons are used in bonding, so there are no mobile charged particles
5. an allotrope of carbon
-different forms of the same element
USES OF DIAMOND
1. as tips of drills to drill through the ground/seabed (due to hardness)
2. grinding (hardness again)
3. polishing
GRAPHITE
1. made of flat layers of carbon atoms. layers have weak van der waal's forces between them. each carbon atom is covalently bonded to three others.
2. "soft” and slippery
- the layers have weak van der waal's forces between them, and slide off easily, giving the impression that it is soft.
3. high melting point (3652-3697 degC) and boiling point (4200 degC)
- covalent bonds between carbon atoms within each layer need a lot of heat energy to break
4. can conduct electricity
- unlike diamond each atom is bonded to three others so there is one extra delocalised electron that is free and mobile and thus graphite can conduct electricity because there are charged particles
5. an allotrope of carbon
- in fact, graphite is the stablest allotrope of carbon, even diamond will become graphite. you can like observe it (but WAIT LONG LONG!)
USES OF GRAPHITE
1. lubricant (soft and slippery to reduce friction, and can be used at high temperatures as well due to high MP and BP)
2. pencil lead (soft, layers slide off onto paper and stick there)
3. inert electrode for electrophoresis (good conductor of electricity)
RECOMMENDED TIME ALLOCATION
RECOMMENDED TIME ALLOCATION FOR EXAMS!
Language Arts: Compo (55min), Unseen (55min), checking (5min). Paper 2: compre+vocab (50min), summary (25min), aq (25min), checking (5min).
Math: dunno...8 to 9 minutes per question?
HCL: zonghe (10min), lijie1 (15min), lijie2 (1h20min), suoduan (15min)
SS: sourcebased (45min), structured (45min)
chem: MCQ each question about 1 minute plus, leave moles to last.
(bio and physics about the same i guess, since same format. anyone wants to edit please do so. and add the geog and history and bsp. if you want to!)
Language Arts: Compo (55min), Unseen (55min), checking (5min). Paper 2: compre+vocab (50min), summary (25min), aq (25min), checking (5min).
Math: dunno...8 to 9 minutes per question?
HCL: zonghe (10min), lijie1 (15min), lijie2 (1h20min), suoduan (15min)
SS: sourcebased (45min), structured (45min)
chem: MCQ each question about 1 minute plus, leave moles to last.
(bio and physics about the same i guess, since same format. anyone wants to edit please do so. and add the geog and history and bsp. if you want to!)
Wednesday, September 28, 2005
CHEMISTRY - Ammonia and Sulphuric Acid
Nitrogen and Hydrogen can produce Ammonia (l). It is done by the Haber process, discovered (or whatever) by Fritz Haber. Was he French? I thought he was French but oh well who cares.
It is a reversible process. Remember your double headed arrow because it is reversible.
Remember to learn how to label the diagram. Only about 10% of the nitrogen and hydrogen are made into ammonia and the rest of it is return so as to save cost. There is also a heat regulator using water but I don't think this is very important HAHA.
The ---BELL JUST RANG. CONTINUE WHEN I GET HOME!
It is a reversible process. Remember your double headed arrow because it is reversible.
Remember to learn how to label the diagram. Only about 10% of the nitrogen and hydrogen are made into ammonia and the rest of it is return so as to save cost. There is also a heat regulator using water but I don't think this is very important HAHA.
The ---BELL JUST RANG. CONTINUE WHEN I GET HOME!
CHEMISTRY - Tips
Hello. Er this is quite wuliao lah since I'm just typing out what Mr Kuo said? Haha.
- Skip mole calculation questions for MCQ. They are there to make you lose track of time!
- Do other questions first. Like duh isn't that the same point. HAHA.
- Actually that was the only thing wasn't it? (:
- Skip mole calculation questions for MCQ. They are there to make you lose track of time!
- Do other questions first. Like duh isn't that the same point. HAHA.
- Actually that was the only thing wasn't it? (:
Saturday, September 24, 2005
GEOG - CLIMATIC HAZARDS
Droughts: unusually long dry period when there is a shortage of water for human, animal use, cultivation
-due to prolonged period of reduction of rainfall ovr an area which causes less water stored in grd, rivers
Effects: 1. farming: ground too dry for crops and plants to grow well and healthily > expensive
2. increased meat price: higher price of animal feed
3. loss of crops & death of livestock
4. famine: insufficient food
Sahel: long belt of land bordering the southern part of the Sahara, stretches 5000km right across Africa
-frm Mauritania & Senegal to Sudan & Ethopia
-annual rainfall btwn 300mm-600mm
-savannah: tall grasses, scrubs & scattered trees
Desertification: 1. climatic change: low rainfall, drying up of land & water bodies, vegetation dies, barren ground, soil erosion
2. overcultivation: no time for replenishing of nutrients, soil structure destroyed, soil erosion
3. deforestation: less interception, fewer roots to bind soil, ground exposed, soil erosion
4. overgrazing: grass cannot re-establish, soil structure destroyed, soil erosion
Causes: 1. droughts: baked land is difficult to plough & useless for grazing; bush fires destroy grassland & crops; top soil is converted to dust
2. overcultivation: rapid population growth; need for more food; land is not given time to rest
-makes soil susceptible to soil erosion
3. deforestation: increased population: trees cut down to provide wood; fewer roots; erosion
4. overgrazing: nomadic tribes try to enlarge their livestock; hooves destroy soil structure
Effects: 1. malnutrition, starvation, famines, diseases
2. ecological refugees: farmers moved to cities
3. walk further for water & firewood
Measures to prevent: 1. sinking >1500 wells in Mali for growing vegetables
2. practise water harvesting: create small stone walls to interrupt rainfall so it infiltrates into soil
3. planting trees in Senegal, Ethiopia: reduce wind velocity, protect top soil from erosion
Floods: body of water that covers usually dry area
Factors: 1.basin size, shape, relief: smaller and more circular basin, steep sided: shorter lag time
2. types of precipitation: prolonged heavy rain, intense storms: saturated ground, more surface runoff
snow: water held in storage, river level drops; reaches river when temperature rises & snow melts
3. landuse: vegetation intercepts rainfall, reduce throughflow; water cannot infiltrate concrtete, water is carried quickly to rivers via drains & gutters
4. permeability: permeable rocks allow rapid infiltration; sandy soil more porous, allow rapid infiltration; clays less porous, more surface runoff
5. storm surges: when water in the sea is raised to a great height by strong onshore winds blowing ovr it
-gigantic wave formed that breaks upon the land & floods it when it reaches the coast
Effects: 1. destroy dams & other structures & habitats
2, sweep away people & property
3. disrupt water & electricity supply, communications
4. widespread famine, diseases: cholera, typhoid fvr
Benefits: 1. fertile soil: alluvium deposits in water
2. irrigation: readily available water
3. gentle relief: favour farming & settlements; easy to build houses & use machines
4. cheap & easy water transport
5. some ppl are ignorant of disastrous consequences
Prevention: 1. channelisation: deepening, widening, clearing or lining of river channel with concrete: water flow away faster (expensive & impractical)
2. building levees: reinforce & increase height of river’s sides to reduce risk of flooding (however, if water goes beyond them, they prevent water frm flowing back into the river
3. building a dam across a valley: allows the control of the amt of water & can be used for electricity (expensive; some valleys unsuitable; affect env)
Case study: Bangladesh: causes: 1. low relief: flood plain & delta occupy 80%; land mostly 10m>sea
2. land drainage: ganges, brahmaputra, meghna brg in 2billion tonnes of sediment/yr, raise beds
3. snow melt: may & june: himalayans mtns snow melt
4. monsoon rain: southwest monsoon brgs heavy rainfall; grnd is saturated; increased surface runoff
5. storm surges: april-may, sep-nov, tropical cyclones
-narrowness of bay of Bengal force storm surge to move inland & flood low lying areas
6. deforestation: firewood, construction, agriculture
Effects: water borne diseases contaminated water
Nov1970: 8m high, powerful winds, 80% rice
Sep 1988: 75% flooded, rds & bridges damaged
1991: 6m high, 1milion tones of rice washed into sea
Tropical storms: violent swirling winds; intense low pressure systems; accompanied by strong winds
-originate ovr seas & oceans (btwn 6oN/S & 20oN/S)
-in summer & autumn (sea surface >27oC)
Formation: 1. air ovr oceans get heat, expand & rise
2. creates low pressure>air frm surrounding rush in a spiralling manner to replace rising warm air
3. air may spin at 200km/h, absorbs large amt of moisture; forms cumulonimbus & heavy rain
4. fades as it reaches land as no more moist air
-calm dry weather in eye (30-50kmD) lowest pressure due to descending cold air
-surrounded by wall of high cumulonimbus clouds under which experiences strong winds & heavy rain
-moist air is drawn to eye
-spirals anti clockwise in N hemi & vice versa
Effects: orissa state, India in 1999: cyclone 300km/h
-released much rain; fast & sudden
-ppl unprepared: 9000 died 200000 houses destroyed; livestock drowned
-international aid called in to help deal with victims
YESSSSS! DONE TYPING GEOG NOTESSS! :))))) this time is wrg it is FOUR FORTY EIGHT AM IN THE MORNING NOW. i shall go slp aft printing them out heeheehee. - lala
-due to prolonged period of reduction of rainfall ovr an area which causes less water stored in grd, rivers
Effects: 1. farming: ground too dry for crops and plants to grow well and healthily > expensive
2. increased meat price: higher price of animal feed
3. loss of crops & death of livestock
4. famine: insufficient food
Sahel: long belt of land bordering the southern part of the Sahara, stretches 5000km right across Africa
-frm Mauritania & Senegal to Sudan & Ethopia
-annual rainfall btwn 300mm-600mm
-savannah: tall grasses, scrubs & scattered trees
Desertification: 1. climatic change: low rainfall, drying up of land & water bodies, vegetation dies, barren ground, soil erosion
2. overcultivation: no time for replenishing of nutrients, soil structure destroyed, soil erosion
3. deforestation: less interception, fewer roots to bind soil, ground exposed, soil erosion
4. overgrazing: grass cannot re-establish, soil structure destroyed, soil erosion
Causes: 1. droughts: baked land is difficult to plough & useless for grazing; bush fires destroy grassland & crops; top soil is converted to dust
2. overcultivation: rapid population growth; need for more food; land is not given time to rest
-makes soil susceptible to soil erosion
3. deforestation: increased population: trees cut down to provide wood; fewer roots; erosion
4. overgrazing: nomadic tribes try to enlarge their livestock; hooves destroy soil structure
Effects: 1. malnutrition, starvation, famines, diseases
2. ecological refugees: farmers moved to cities
3. walk further for water & firewood
Measures to prevent: 1. sinking >1500 wells in Mali for growing vegetables
2. practise water harvesting: create small stone walls to interrupt rainfall so it infiltrates into soil
3. planting trees in Senegal, Ethiopia: reduce wind velocity, protect top soil from erosion
Floods: body of water that covers usually dry area
Factors: 1.basin size, shape, relief: smaller and more circular basin, steep sided: shorter lag time
2. types of precipitation: prolonged heavy rain, intense storms: saturated ground, more surface runoff
snow: water held in storage, river level drops; reaches river when temperature rises & snow melts
3. landuse: vegetation intercepts rainfall, reduce throughflow; water cannot infiltrate concrtete, water is carried quickly to rivers via drains & gutters
4. permeability: permeable rocks allow rapid infiltration; sandy soil more porous, allow rapid infiltration; clays less porous, more surface runoff
5. storm surges: when water in the sea is raised to a great height by strong onshore winds blowing ovr it
-gigantic wave formed that breaks upon the land & floods it when it reaches the coast
Effects: 1. destroy dams & other structures & habitats
2, sweep away people & property
3. disrupt water & electricity supply, communications
4. widespread famine, diseases: cholera, typhoid fvr
Benefits: 1. fertile soil: alluvium deposits in water
2. irrigation: readily available water
3. gentle relief: favour farming & settlements; easy to build houses & use machines
4. cheap & easy water transport
5. some ppl are ignorant of disastrous consequences
Prevention: 1. channelisation: deepening, widening, clearing or lining of river channel with concrete: water flow away faster (expensive & impractical)
2. building levees: reinforce & increase height of river’s sides to reduce risk of flooding (however, if water goes beyond them, they prevent water frm flowing back into the river
3. building a dam across a valley: allows the control of the amt of water & can be used for electricity (expensive; some valleys unsuitable; affect env)
Case study: Bangladesh: causes: 1. low relief: flood plain & delta occupy 80%; land mostly 10m>sea
2. land drainage: ganges, brahmaputra, meghna brg in 2billion tonnes of sediment/yr, raise beds
3. snow melt: may & june: himalayans mtns snow melt
4. monsoon rain: southwest monsoon brgs heavy rainfall; grnd is saturated; increased surface runoff
5. storm surges: april-may, sep-nov, tropical cyclones
-narrowness of bay of Bengal force storm surge to move inland & flood low lying areas
6. deforestation: firewood, construction, agriculture
Effects: water borne diseases contaminated water
Nov1970: 8m high, powerful winds, 80% rice
Sep 1988: 75% flooded, rds & bridges damaged
1991: 6m high, 1milion tones of rice washed into sea
Tropical storms: violent swirling winds; intense low pressure systems; accompanied by strong winds
-originate ovr seas & oceans (btwn 6oN/S & 20oN/S)
-in summer & autumn (sea surface >27oC)
Formation: 1. air ovr oceans get heat, expand & rise
2. creates low pressure>air frm surrounding rush in a spiralling manner to replace rising warm air
3. air may spin at 200km/h, absorbs large amt of moisture; forms cumulonimbus & heavy rain
4. fades as it reaches land as no more moist air
-calm dry weather in eye (30-50kmD) lowest pressure due to descending cold air
-surrounded by wall of high cumulonimbus clouds under which experiences strong winds & heavy rain
-moist air is drawn to eye
-spirals anti clockwise in N hemi & vice versa
Effects: orissa state, India in 1999: cyclone 300km/h
-released much rain; fast & sudden
-ppl unprepared: 9000 died 200000 houses destroyed; livestock drowned
-international aid called in to help deal with victims
YESSSSS! DONE TYPING GEOG NOTESSS! :))))) this time is wrg it is FOUR FORTY EIGHT AM IN THE MORNING NOW. i shall go slp aft printing them out heeheehee. - lala
GEOG - RIVERS
Drainage basin (catchment area): area of land drained by a river & its tributaries
-source: beginning of river
-mouth: where water is emptied
River discharge: volume of water flowing through a particular point in the river in a given time
=area of cross section (m2) X velocity of flow (m/s)
Drainage density: average length or river/unit area
-length of all the streams in drainage basin added up divided by the area of the drainage basin
Drainage patterns: arrangement of a river & its tributaries in a drainage basin
1. dendritic pattern: tributaries flow into main river at acute angles (tree like branching)
-usually develops in area with homogenous rocks or rocks with similar resistance
2. radial pattern: rivers flow down in all directions form a central high point (conical hill / volcano)
3. trellised pattern: developed in area with alternate bands of rocks with different resistance
-tributaries flow along less resistant rock, joins main river at right angles
4. centripetal pattern: common in inland basins & desert regions: streams from various directions drain towards centre of a depression (lake, lowland basin)
Hydrological cycle: 1. infiltration: some water that reaches the ground soaks into the soil subsurface
-some flow sideways as throughflow
-some are absorbed by roots of trees & transpired back to atmosphere
2. percolation: some water moves further down into unsaturated underlying soil & rock layers
-results n large amt of underground water that collects on top of an impermeable rock layer
3. base flow (ground water flow): water that flows sideways frm water table
4.overland flow (surface runoff): when precipitation exceeds infiltration rate > high in urban areas
5. evapotranspiration: loss of moisture frm earth’s surface to atmosphere
-evaporation frm water bodies
- transpiration frm vegetation
Storm hydrograph: shows variations in river discharge at a particular point in a rive over a certain period of time
-river does not rise immediately aft storm starts
-river level rises quickly (steep rising limb) later when surface runoff & throughflow arrive
-peak discharge: river level at its highest
-lag time: difference in time between highest rainfall & peak discharge
-recession limb is not as steep as the rising limb as throughflow is still entering the river
-river is maintained by the base flow after water brought by the storm has drained away
Factors affecting shape of storm hydrograph: 1.basin size, shape, relief: smaller and more circular basin, steep sided: shorter lag time
2. types of precipitation: prolonged heavy rain, intense storms: saturated ground, more surface runoff
snow: water held in storage, river level drops; reaches river when temperature rises & snow melts
3. extreme hot or cold temperature restricts infiltration, increase surface runoff; high evapotranspiration rate, less water flows into river
4. landuse: vegetation intercepts rainfall, reduce throughflow; water cannot infiltrate concrtete, water is carried quickly to rivers via drains & gutters
5. rock type: permeable rocks allow rapid infiltration
6. soil type: sandy soil more porous, allow rapid infiltration; clays less porous, more surface runoff
7. drainage density: higher, greater chance of floods
Energy of river: mostly used to overcome friction with river bed & sides; erosion & transportation
-when energy is low, materials are deposited
-energy depends on velocity of flow & volume
Velocity of river: 1. gradient of land: steeper, faster
2. roughness of channel: rougher, slower
-more energy used to overcome friction
3. shape of channel cross section: more wetted perimeter (length of river sides & bed), more friction
-symmetrical channel: water flows faster mid stream, slower near sides & bed
-asymmetrical channel: water flows faster at concave bank, slower at convex bank due to shallower water
Volume of water: 1. size of drainage basin: larger basin, bigger volume (tributaries increase volume)
2. vegetation cover: thick cover, more interception, less runoff to river
3. rainfall: higher, greater volume
4. temperature: high temperature, high rate of evaporation, less volume
5. permeability of rocks & ground surface: more permeable, less surface runoff, less volume
River erosion: vertical & horizontal erosion
1. abrasion/corrasion: uses river load to grind sides & bed of channel
2. hydraulic action: swift flowing water breaks and loosens rocks
3. attrition: rocks in river load hit again one another, becoming smaller, smoother & more rounded
4. solution/corrosion: river dissolves minerals
River transportation: 1. solution: carries dissolved minerals (calcium & sodium)
2. suspension: fine particles carried (sand silt clay)
3. saltation: gravel, coarse sand bounce on river bed
4. traction: bigger pebbles & boulders rolled along
_saltation & traction loads form the bedload
River deposition: when volume & speed of water decreases; carry a greater load than it can support
Volume decreases when: 1. little or rain falls
2. flows across arid area with high evaporation rate
3. flows across permeable rocks
4. flood water brought by storm has drained away
Speed decreases when: 1. sudden change of gradient
2. river flows into another body of water
3. increase in wetted perimeter: more friction
4. water flowing in shallow section (convex bank of meander) encounters friction
5. obstructions (mounds of deposits & protruding rocks) roughen channel & increase friction
_heaviest materials are deposited first
Course of river: 1. upper: a. river channel: small, narrow rough, usually shallow
b. river valley: deep, narrow, steep sided, v shaped
c. work of river: most energy used to overcome friction of rough channel, little energy for erosion
-during heavy downpour, increased volume enables vertical erosion: bedload swirls in whirlpool
-headward erosion: throughflow reaches surface & undercuts the overlying rocks & soil
d. landforms: i. rapids: short & fast flowing turbulent falls of water along a river; water is quite shallow
-alternating bands of resistant & less resistant rocks: less resistant rocks are eroded faster
ii. waterfalls: sudden fall of water vertically+rapidly
_formed when river flows frm a band of resistant rock to less resistant rock (Niagara falls)
-resistant rock can be vertical (sill), horizontal or dip upstream (dyke)
-less resistant rock downstream erodes faster: causes change in gradient of river
_formed when faulting causes land to be displaced
-difference in height causes water to cascade down
-waterfall retreats upstream, gorge is formed at downstream part of waterfall (Victoria falls Africa)
iii. plunge pools: depression at foot of waterfall
-enlarge & deepened by hydraulic action of plunging water; rock debris swirled abt > abrasion
iv. gorge: deep narrow valley w very steep sides
-formed when waterfall retreats upstream
v. potholes: depressions in river bed
-formed by abrasion: pebbles trapped in slight hollows & swirled about in the currents & turbulence of fast flowing water; enlarge & deepen the holes
2. middle: a. river channel: wider & deeper; asymmetrical cross section; meanders; bigger volume of water; less gradient
b. river valley: more open v shape - lateral erosion
- weathering & mass wasting of river sides
c. work of river: gentler gradient less vertical erosion
-increased volume & load used for lateral erosion
-energy used to transport load
-deposition occurs on meander convex banks
d. landforms: meanders, river cliffs, slip off slopes
meanders: forms when river meets an obstacle; erode and undercuts concave banks at outer bends
-water moves in a spiral manner, fast at concave
-materials deposited at convex: slow due to friction
3. lower: a. river channel: widest & deepest, smooth channel floor; irregularities in bed filled w sediment
-largest volume due to tributaries
b. river valley: wide & flat bottomed: lateral erosion
c. work of river: lateral erosion on concave banks of meanders; to deposit the load it is transporting
d. landforms: i. flood plains: wide & low lying plain found on both sides of river; covered by deposition
levees: embankments found along banks, coarser
-during heavy rain water overflows, meets friction
-deposits coarse material first (levee)
-smaller & lighter material deposited further away
ii. ox bow lakes: horseshoe or crescent shaped lakes
-cut off from river when narrow neck separating 2 ends of a meander is broken by lateral erosion on the concave banks or strong currents during a flood
-the ends are sealed by deposits on convex bank
-lake may dry up due to evaporation & percolation
iii. deltas: flat depositional plain at river mouths
-formed if load removal is slower than deposition
-water enters sea at individual mouths
1. active erosion in upper cause: enhance load
2. presence of shallow sea at river mouth
3. presence of gentle shope near shore
4. sheltered bay where tides are calm & weak
5. absence of large lakes along river course that might reduce the load
Shapes: 1. arcuate: triangular or fan shaped; deposits evenly spread out (nile delta)
2. bird’s foot: irregular shape; deposits unloaded rapidly at river mouth (Mississippi delta)
3. compound delta: complex in shape
4. estuarine delta: formed by infilling of an estuary
Uses of rivers: 1. hydro electric power: dams
2. irrigation: impt in drought prone areas
3. fertile alluvial soil: rice growing
4. transport, ports, harbours: cheap (chang jiang)
5. domestic uses: food, water for drinking, cooking
6. tourist attractions & recreational
Problems caused: 1. flooding: damage & loss of property & lives (huang he)
2. pollution: not suitable for drinking
OMG SO MANY THGS TO RMB!!! >.< - lala
-source: beginning of river
-mouth: where water is emptied
River discharge: volume of water flowing through a particular point in the river in a given time
=area of cross section (m2) X velocity of flow (m/s)
Drainage density: average length or river/unit area
-length of all the streams in drainage basin added up divided by the area of the drainage basin
Drainage patterns: arrangement of a river & its tributaries in a drainage basin
1. dendritic pattern: tributaries flow into main river at acute angles (tree like branching)
-usually develops in area with homogenous rocks or rocks with similar resistance
2. radial pattern: rivers flow down in all directions form a central high point (conical hill / volcano)
3. trellised pattern: developed in area with alternate bands of rocks with different resistance
-tributaries flow along less resistant rock, joins main river at right angles
4. centripetal pattern: common in inland basins & desert regions: streams from various directions drain towards centre of a depression (lake, lowland basin)
Hydrological cycle: 1. infiltration: some water that reaches the ground soaks into the soil subsurface
-some flow sideways as throughflow
-some are absorbed by roots of trees & transpired back to atmosphere
2. percolation: some water moves further down into unsaturated underlying soil & rock layers
-results n large amt of underground water that collects on top of an impermeable rock layer
3. base flow (ground water flow): water that flows sideways frm water table
4.overland flow (surface runoff): when precipitation exceeds infiltration rate > high in urban areas
5. evapotranspiration: loss of moisture frm earth’s surface to atmosphere
-evaporation frm water bodies
- transpiration frm vegetation
Storm hydrograph: shows variations in river discharge at a particular point in a rive over a certain period of time
-river does not rise immediately aft storm starts
-river level rises quickly (steep rising limb) later when surface runoff & throughflow arrive
-peak discharge: river level at its highest
-lag time: difference in time between highest rainfall & peak discharge
-recession limb is not as steep as the rising limb as throughflow is still entering the river
-river is maintained by the base flow after water brought by the storm has drained away
Factors affecting shape of storm hydrograph: 1.basin size, shape, relief: smaller and more circular basin, steep sided: shorter lag time
2. types of precipitation: prolonged heavy rain, intense storms: saturated ground, more surface runoff
snow: water held in storage, river level drops; reaches river when temperature rises & snow melts
3. extreme hot or cold temperature restricts infiltration, increase surface runoff; high evapotranspiration rate, less water flows into river
4. landuse: vegetation intercepts rainfall, reduce throughflow; water cannot infiltrate concrtete, water is carried quickly to rivers via drains & gutters
5. rock type: permeable rocks allow rapid infiltration
6. soil type: sandy soil more porous, allow rapid infiltration; clays less porous, more surface runoff
7. drainage density: higher, greater chance of floods
Energy of river: mostly used to overcome friction with river bed & sides; erosion & transportation
-when energy is low, materials are deposited
-energy depends on velocity of flow & volume
Velocity of river: 1. gradient of land: steeper, faster
2. roughness of channel: rougher, slower
-more energy used to overcome friction
3. shape of channel cross section: more wetted perimeter (length of river sides & bed), more friction
-symmetrical channel: water flows faster mid stream, slower near sides & bed
-asymmetrical channel: water flows faster at concave bank, slower at convex bank due to shallower water
Volume of water: 1. size of drainage basin: larger basin, bigger volume (tributaries increase volume)
2. vegetation cover: thick cover, more interception, less runoff to river
3. rainfall: higher, greater volume
4. temperature: high temperature, high rate of evaporation, less volume
5. permeability of rocks & ground surface: more permeable, less surface runoff, less volume
River erosion: vertical & horizontal erosion
1. abrasion/corrasion: uses river load to grind sides & bed of channel
2. hydraulic action: swift flowing water breaks and loosens rocks
3. attrition: rocks in river load hit again one another, becoming smaller, smoother & more rounded
4. solution/corrosion: river dissolves minerals
River transportation: 1. solution: carries dissolved minerals (calcium & sodium)
2. suspension: fine particles carried (sand silt clay)
3. saltation: gravel, coarse sand bounce on river bed
4. traction: bigger pebbles & boulders rolled along
_saltation & traction loads form the bedload
River deposition: when volume & speed of water decreases; carry a greater load than it can support
Volume decreases when: 1. little or rain falls
2. flows across arid area with high evaporation rate
3. flows across permeable rocks
4. flood water brought by storm has drained away
Speed decreases when: 1. sudden change of gradient
2. river flows into another body of water
3. increase in wetted perimeter: more friction
4. water flowing in shallow section (convex bank of meander) encounters friction
5. obstructions (mounds of deposits & protruding rocks) roughen channel & increase friction
_heaviest materials are deposited first
Course of river: 1. upper: a. river channel: small, narrow rough, usually shallow
b. river valley: deep, narrow, steep sided, v shaped
c. work of river: most energy used to overcome friction of rough channel, little energy for erosion
-during heavy downpour, increased volume enables vertical erosion: bedload swirls in whirlpool
-headward erosion: throughflow reaches surface & undercuts the overlying rocks & soil
d. landforms: i. rapids: short & fast flowing turbulent falls of water along a river; water is quite shallow
-alternating bands of resistant & less resistant rocks: less resistant rocks are eroded faster
ii. waterfalls: sudden fall of water vertically+rapidly
_formed when river flows frm a band of resistant rock to less resistant rock (Niagara falls)
-resistant rock can be vertical (sill), horizontal or dip upstream (dyke)
-less resistant rock downstream erodes faster: causes change in gradient of river
_formed when faulting causes land to be displaced
-difference in height causes water to cascade down
-waterfall retreats upstream, gorge is formed at downstream part of waterfall (Victoria falls Africa)
iii. plunge pools: depression at foot of waterfall
-enlarge & deepened by hydraulic action of plunging water; rock debris swirled abt > abrasion
iv. gorge: deep narrow valley w very steep sides
-formed when waterfall retreats upstream
v. potholes: depressions in river bed
-formed by abrasion: pebbles trapped in slight hollows & swirled about in the currents & turbulence of fast flowing water; enlarge & deepen the holes
2. middle: a. river channel: wider & deeper; asymmetrical cross section; meanders; bigger volume of water; less gradient
b. river valley: more open v shape - lateral erosion
- weathering & mass wasting of river sides
c. work of river: gentler gradient less vertical erosion
-increased volume & load used for lateral erosion
-energy used to transport load
-deposition occurs on meander convex banks
d. landforms: meanders, river cliffs, slip off slopes
meanders: forms when river meets an obstacle; erode and undercuts concave banks at outer bends
-water moves in a spiral manner, fast at concave
-materials deposited at convex: slow due to friction
3. lower: a. river channel: widest & deepest, smooth channel floor; irregularities in bed filled w sediment
-largest volume due to tributaries
b. river valley: wide & flat bottomed: lateral erosion
c. work of river: lateral erosion on concave banks of meanders; to deposit the load it is transporting
d. landforms: i. flood plains: wide & low lying plain found on both sides of river; covered by deposition
levees: embankments found along banks, coarser
-during heavy rain water overflows, meets friction
-deposits coarse material first (levee)
-smaller & lighter material deposited further away
ii. ox bow lakes: horseshoe or crescent shaped lakes
-cut off from river when narrow neck separating 2 ends of a meander is broken by lateral erosion on the concave banks or strong currents during a flood
-the ends are sealed by deposits on convex bank
-lake may dry up due to evaporation & percolation
iii. deltas: flat depositional plain at river mouths
-formed if load removal is slower than deposition
-water enters sea at individual mouths
1. active erosion in upper cause: enhance load
2. presence of shallow sea at river mouth
3. presence of gentle shope near shore
4. sheltered bay where tides are calm & weak
5. absence of large lakes along river course that might reduce the load
Shapes: 1. arcuate: triangular or fan shaped; deposits evenly spread out (nile delta)
2. bird’s foot: irregular shape; deposits unloaded rapidly at river mouth (Mississippi delta)
3. compound delta: complex in shape
4. estuarine delta: formed by infilling of an estuary
Uses of rivers: 1. hydro electric power: dams
2. irrigation: impt in drought prone areas
3. fertile alluvial soil: rice growing
4. transport, ports, harbours: cheap (chang jiang)
5. domestic uses: food, water for drinking, cooking
6. tourist attractions & recreational
Problems caused: 1. flooding: damage & loss of property & lives (huang he)
2. pollution: not suitable for drinking
OMG SO MANY THGS TO RMB!!! >.< - lala
GEOG - WEATHERING
Denudation: weathering down of earth’s surface through weathering, mass wasting & erosion
Weathering: disintegration & decomposition of rocks in situ; no transport involved
Mass wasting: movement of surface material down a slope due to gravity
Erosion: wearing away of rocks by moving agents & removal from their original site
Physical: breaking of rocks into smaller pieces
-size & shape altered but not chemical composition
-products are usually coarse & angularmost effective in areas with: 1. little vegetation
2. large diurnal temperature range
3. temperatures fluctuating around 0oC
Types: 1. frost shattering: water that enters the joints in rocks freezes and expands at night, causing stress on the rocks; rock breaks after many repetitions
-angular rock fragments gather at foot of slope to form scree slope
-ice crystals may grow in rock pores
2. block disintegration: splitting of rocks along the joints into blocks
3. exfoliation: outer layer of rocks expand in day & contract at night; cracks are formed, layers peel off
4. granular disintegration: different coloured mineral grains expand & contract at different rates; causes stress & rock will disintegrate grain by grain
5. salt crystal growth: in arid regions; water evaporates, leaving behind salt crystals in rock pores
-grow & swell, causing stress & rock slowly break up
6. hydration: some minerals swell as they absorb water; causes stress & weakens rock. Chemical structure is also changed when this happens
7. pressure release: when overlying rock material is eroded, the intrusive igneous rocks are exposed
-outer parts expand; causes stress; fractures form parallel to rock surface & break away
Chemical: decomposition of rocks when minerals in the rocks react chemically with rainwater, seawater, CO2 & O2 to form new chemical compounds
-alters physical structure & chemical composition
-effective in hot & wet areas
-weakens the rocks that break down over time
Types: 1. solution: more soluble minerals dissolve; parts of rock crumble off
2. carbonation: carbonic acid formed by CO2 & rainwater react with limestone to form a soluble substance calcium hydrogen carbonate
-enlarged & deepened joint: grike
-flat topped blocks btwn grikes: clint
-stalactites on roof & stalagmites on ground
3. hydrolysis: chemical reaction btwn some of the minerals in rocks and rainwater
In granite: consisting of feldspar, mica & quartz
-feldspar changes into clay that crumbles easily
-iron in mica is oxidised; quartz is unaltered
4. oxidation: chemical reaction btwn oxygen in air & water and the minerals in rocks
5. acid rain: rain absorbs sulphuric & nitric acids frm burning of fossil fuels; weathers rocks
Biological: can be a physical or a chemical process
1. roots of trees & plants grow in joints of rocks: exert pressure; widen & deepen them; rock structure loosened; enables other types of weathering to work
2. burrowing animals pry open cracks in rocks: exposes the rocks to other types of weathering
3. overgrazing: soil erosion; rocks exposed
4. humic acids frm decaying plants react chemically
Factors that affect rate & type of weathering
1. rock hardness: depends on minerals in rock
-igneous rocks: hard; sedimentary rocks: softer
-harder rock more resistant to weathering
2. mineral composition: impt influence ovr chemical weathering; some effect on physical weathering
_quartz more resistant to chemical
-basalt rock & limestone less resistant
_darker coloured minerals heat up faster
-darker basalt rocks weather faster physically
3. grain size: coarse grained decompose faster
-granite weather faster than rhyolite
-due to large gaps aft being hydrolysed
4. lines of weaknesses: well jointed weathers faster
-more rock surface exposed to weathering
5. relief: physical weathering more active on steep slopes: landslides; frost action etc on exposed rocks
-less chemical as water flows away more easily
Chemical weathering more active on flat land as water is retained and can act on underlying rocks
-less physical as rocks are sheltered by soil
6. vegetation cover: more weathering
-retains rainwater; humic & organic acid; roots grow
7. human activities: sulphur dioxide & nitrogen oxide acid rain; expose rocks when clearing land dvlpmnt
8. climate: a. temperature: big range > exfoliation
-fluctuate arnd 0oC > frost action
-high evaporation rate > salt crystal growth
-high humidity: water retained
-high temperature > faster rate of chemical
b. rainfall: heavy + high temperature > hydrolysis, carbonation, oxidation, fast plant growth
Weathering: disintegration & decomposition of rocks in situ; no transport involved
Mass wasting: movement of surface material down a slope due to gravity
Erosion: wearing away of rocks by moving agents & removal from their original site
Physical: breaking of rocks into smaller pieces
-size & shape altered but not chemical composition
-products are usually coarse & angularmost effective in areas with: 1. little vegetation
2. large diurnal temperature range
3. temperatures fluctuating around 0oC
Types: 1. frost shattering: water that enters the joints in rocks freezes and expands at night, causing stress on the rocks; rock breaks after many repetitions
-angular rock fragments gather at foot of slope to form scree slope
-ice crystals may grow in rock pores
2. block disintegration: splitting of rocks along the joints into blocks
3. exfoliation: outer layer of rocks expand in day & contract at night; cracks are formed, layers peel off
4. granular disintegration: different coloured mineral grains expand & contract at different rates; causes stress & rock will disintegrate grain by grain
5. salt crystal growth: in arid regions; water evaporates, leaving behind salt crystals in rock pores
-grow & swell, causing stress & rock slowly break up
6. hydration: some minerals swell as they absorb water; causes stress & weakens rock. Chemical structure is also changed when this happens
7. pressure release: when overlying rock material is eroded, the intrusive igneous rocks are exposed
-outer parts expand; causes stress; fractures form parallel to rock surface & break away
Chemical: decomposition of rocks when minerals in the rocks react chemically with rainwater, seawater, CO2 & O2 to form new chemical compounds
-alters physical structure & chemical composition
-effective in hot & wet areas
-weakens the rocks that break down over time
Types: 1. solution: more soluble minerals dissolve; parts of rock crumble off
2. carbonation: carbonic acid formed by CO2 & rainwater react with limestone to form a soluble substance calcium hydrogen carbonate
-enlarged & deepened joint: grike
-flat topped blocks btwn grikes: clint
-stalactites on roof & stalagmites on ground
3. hydrolysis: chemical reaction btwn some of the minerals in rocks and rainwater
In granite: consisting of feldspar, mica & quartz
-feldspar changes into clay that crumbles easily
-iron in mica is oxidised; quartz is unaltered
4. oxidation: chemical reaction btwn oxygen in air & water and the minerals in rocks
5. acid rain: rain absorbs sulphuric & nitric acids frm burning of fossil fuels; weathers rocks
Biological: can be a physical or a chemical process
1. roots of trees & plants grow in joints of rocks: exert pressure; widen & deepen them; rock structure loosened; enables other types of weathering to work
2. burrowing animals pry open cracks in rocks: exposes the rocks to other types of weathering
3. overgrazing: soil erosion; rocks exposed
4. humic acids frm decaying plants react chemically
Factors that affect rate & type of weathering
1. rock hardness: depends on minerals in rock
-igneous rocks: hard; sedimentary rocks: softer
-harder rock more resistant to weathering
2. mineral composition: impt influence ovr chemical weathering; some effect on physical weathering
_quartz more resistant to chemical
-basalt rock & limestone less resistant
_darker coloured minerals heat up faster
-darker basalt rocks weather faster physically
3. grain size: coarse grained decompose faster
-granite weather faster than rhyolite
-due to large gaps aft being hydrolysed
4. lines of weaknesses: well jointed weathers faster
-more rock surface exposed to weathering
5. relief: physical weathering more active on steep slopes: landslides; frost action etc on exposed rocks
-less chemical as water flows away more easily
Chemical weathering more active on flat land as water is retained and can act on underlying rocks
-less physical as rocks are sheltered by soil
6. vegetation cover: more weathering
-retains rainwater; humic & organic acid; roots grow
7. human activities: sulphur dioxide & nitrogen oxide acid rain; expose rocks when clearing land dvlpmnt
8. climate: a. temperature: big range > exfoliation
-fluctuate arnd 0oC > frost action
-high evaporation rate > salt crystal growth
-high humidity: water retained
-high temperature > faster rate of chemical
b. rainfall: heavy + high temperature > hydrolysis, carbonation, oxidation, fast plant growth
GEOG - PLATE TETONICS & RESULTING LANDFORMS
OCEANIC___________________CONTINENTAL
Sima (silicon + magnesium)_______Sial (silicon + aluminium)
Mainly basaltic________________Mainly granite
Thinner (5-10km)______________Thicker (35-40. 60-70km under mountain )
Denser (3g/cm3)_______________Less Dense (2.7g/cm3)
Younger_____________________Older
More continuous_______________Less continuous
Continental Drift – Alfred Wegner: started as Pangaea, drifted apart, formed current continents
-cause: convection currents-magma in mantle heats up, expands & rises, spread outs, cools, sinks, repeat
Evidence: 1. coastlines of continents fit together like jigsaw puzzle pieces (e.g. Africa and South America)
2. similar fossil of reptile found (e.g. Africa and South America)
3. identical fossil fern found (all southern continents)
4. rocks of same age and geological structure ( e.g. SW Africa and SE Brazil)
5. coal (which is formed under warm and wet conditions) found under Antarctic icecap
Plate Movements
Divergent (O&O): plates move apart
-tensional stresses cause fractures to occur
é new basaltic magma wells up, some melt
é erupts on surface as lava
é inject near the surface
é crystallize as igneous rocks
é become new sea floor, sea floor spreading
é forms oceanic ridges
é more basaltic magma piles up and solidifies
é forms a chain of mountains
é plates continue to move apart
é mountain move away from spreading zone
é youngest closest and oldest furthest
é earthquakes occur, volcanic activity
é basaltic magma escapes up fractures
é form submarine rift volcanoes
C&C: plates move apart
é faulting occurs, causes earthquake
é no new crust form
é formation of new sea (e.g. red sea)
é magma flows up cracks in crust
é volcanoes formed
Convergent (O&O):plates edges bent into deep oceanic trench [e.g. Marianas Trench in Pacific Ocean (Pacific plate dives below Philippines)]
é plate with lower percentage of continental crust would subduct
é subduction zone, subducting plate melts under high heat and friction
é silica-rich magma produced
é form chain of subduction volcanoes- island arc
é earthquake occurs: downward movement of subducting plate is not smooth
O&C: thinner and denser oceanic plate subducts
é long, narrow and deep oceanic trench is formed (e.g. Peru-Chile Trench off South American coast)
é faulting occurs, earthquake occurs
é downwards movement of plate not smooth
é subducting plate melts under high heat and friction, silica-rich magma formed
é being less dense, magma rises up fractures
é escapes through vents to the land surface
é forms subduction volcanoes
é continental late contorted and folded
é form fold mountains
C&C: no subduction
é one may be pushed under the other for a short distance
é both light and buoyant, no volcanic activity
é folding occurs, produce great uplift and highly contorted fold mountain ranges
é e.g. Himalayan Mountains (Indo-Australian and Eurasian)
é faulting and earthquakes
Transform: same direction @ diff speeds
é Pacific Plate and North American plate along the San Andreas Fault
é lithospheric material neither created not destroyed
é plates moving in different directions
é jerky movements causes earthquakes
é no volcanic activity
fold mountains: fold is a bend in rock strata
anticline: hill syncline: valley
folds: 1. simple fold: limbs with same steepness
2. asymmetrical fold: uneven limbs, uneven forces
3. overfold: both limbs sloping in same direction
4. recumbent fold: axis of fold is almost horizontal
5. overthrust fold: fractured recumbent fold
Circum pacific region: rocky mtns & andes, island arcs (japan & the philippines)
Eurasion Indonesian belt: atlas mtns Africa; alps southern Europe; Himalayas northern India
Himalayas mtns: indo-australian & Eurasian plates
-tethys sea separating India & asia subducted under Eurasian plate
-when asia & India continental mass met, folding of sediments occurred as there was no subduction
Andes mtns: nazca & south American plates
-oceanic nazca sinks under continental SA plate, being thinner and denser
-sediment on the ocean floor squeezed & crumpled
-silica rich magma rose thru fractures: subduction vol
Faulting: break or fracture in rocks where they are displaced. caused by stresses & strains
1. normal fault: tension; lithosphere is pulled apart
- one blocked lowered; forms steep scarp/cliff
2. reverse fault: compression; one block rises, forms overhanging escarpment which may be eroded
3. transform fault: adjacent blocks slide past horizontally along the fracture
Horst(block mtn): uplifted block w/ steep fault scarps
-caused by tension or compression
Tilt block: block mtn w one scarp
Rift valley/graben: elongated deep valley
-caused by tension or compression
-parallel faults form stepped scarps
-magma rises to form rift volcanoes at sides
Lava: lower silica content >higher temperature & more fluid
Basic: low silica content, fluid, rich in iron & magnesium, hot abt 1200oC, flows slowly & far
-produced at constructive boundaries
-quiet explosion as it allows expanding gases to escape easily thru the vent
-forms gently sloping volcanoes 2o-10o
Acid: high silica content, viscous, not so hot 800oC, solidifies quickly, does not flow far
-produced at destructive boundaries
-violent explosion as lava solidifies quickly & blocks the upward movement of expanding gases
-forms steep sided volcanoes
Lava plateau: built up by basaltic lava frm fissures
-spread ovr large area, solidifies: Columbia plateau
Volcano: 1. conical or dome shaped
2. crater: throws out gases, pyroclasts & lava
-enlarged crater (>1kmD) caldera; may contain lake
-caldera formed when removal of magma is faster than it can be replenished so summit collapses into magma chamber of volcano
3. magma flows frm magma chamber to pipe to vent
4. composite volcano may have a secondary cone
Active: erupts frequently & in recent times
Dormant: not erupted recently but not extinct
Extinct: does not erupt anymore
Formation: magma rises up fractures in rocks; pressure is reduced when it moves upwards: allows gases to expand & volcanic material to be ejected
-volcanic material piles up arnd vent, forms volcano
Gases: steam, carbon dioxide, sulphur dioxide
Solids: ash, dust, volcanic bombs, cinder (pyroclasts)
types: 1. ash & cinder volcano: steep sided, gentle base symmetrical; formed frm hot ash & red hot cinders; bowl shaped summit crater
2. basic lava volcano(shield):wide base gentle slopes
Hot spot volcanoes: mauna loa in Hawaii
-far away frm plate boundary
Basaltic magma issues thru a vent to form volcano
-plate moves, chain of volcanic islands formed
3. lava dome: acid lava too viscous & solidifies ovr vent to form a bulbous structure. Sides become steep and dome shaped when lava fills up the interior
4. volcanic plug: viscous acid lava solidified in central pipe and forms a spine or volcanic plug
5. composite volcano: alternate layers of pyroclasts & viscous acid lava; steeper towards top, gentler at base – composite cones formed when lava flows out of secondary pipes
6. minor features associated with vulcanicity
a. volcanic hot spring
b. geyser: violent ejection of hot water
problems: 1. massive destruction: of lives & property; interrupt communication; gases (CO2) suffocate ppl
2. tsunamis: eruptions near coast create huge waves
3. pollution: damage respiratory systems; contaminate water sources
4. steam affects rain; sulphur affects ozone layer
Benefits: 1. weathered volcanic materials make good fertile soil with necessary minerals for cultivation
2. precious stones & minerals: mining
3. tourism: hot springs resorts, attractions
4. geothermal energy (heat below earth’s surface): produce electricity, warm houses
Earthquakes: occurs when energy built up in earth’s crust is suddenly released
-occurs when convergent movement is not smooth
-stress in rocks so great that causes the ground to vibrate when the rocks jerk free
1. focus: source of earthquake
2. epicentre: point on surface directly above focus
3. seismic waves: measured by seismograph
4. Richter scale0-9: measure amt of energy released
Problems: 1. destroy buildings & roads : toppled over, hinders rescue work
2. disrupts water, gas & electricity supplies & communication: burst pipes, broken telephone lines; fires formed, diseases rampant -water contaminated
3. causes landslides & tsunamis
Factors affecting extent of damage: 1. magnitude
2. depth of focus: shallow focus, large extent
3. epicentre: nearer, larger damage; more solid rock epicentre, less damage
4. constructions: dense built up buildings, more damage; flimsy old building cannot withstand
5. forecast: prediction & preparation help
6. tsunamis: no tsunami, less damage
Ways to reduce damage: 1. location, design & materials of buildings: don’t build on active fault zone;unstable soil, use shock absorbing rubber blocks
2. limit outbreak of fires: use fireproof materials
3. conduct drills; preparation: familiarise people with emergency procedures; have enough supplies
4. prediction & warning systems
Sima (silicon + magnesium)_______Sial (silicon + aluminium)
Mainly basaltic________________Mainly granite
Thinner (5-10km)______________Thicker (35-40. 60-70km under mountain )
Denser (3g/cm3)_______________Less Dense (2.7g/cm3)
Younger_____________________Older
More continuous_______________Less continuous
Continental Drift – Alfred Wegner: started as Pangaea, drifted apart, formed current continents
-cause: convection currents-magma in mantle heats up, expands & rises, spread outs, cools, sinks, repeat
Evidence: 1. coastlines of continents fit together like jigsaw puzzle pieces (e.g. Africa and South America)
2. similar fossil of reptile found (e.g. Africa and South America)
3. identical fossil fern found (all southern continents)
4. rocks of same age and geological structure ( e.g. SW Africa and SE Brazil)
5. coal (which is formed under warm and wet conditions) found under Antarctic icecap
Plate Movements
Divergent (O&O): plates move apart
-tensional stresses cause fractures to occur
é new basaltic magma wells up, some melt
é erupts on surface as lava
é inject near the surface
é crystallize as igneous rocks
é become new sea floor, sea floor spreading
é forms oceanic ridges
é more basaltic magma piles up and solidifies
é forms a chain of mountains
é plates continue to move apart
é mountain move away from spreading zone
é youngest closest and oldest furthest
é earthquakes occur, volcanic activity
é basaltic magma escapes up fractures
é form submarine rift volcanoes
C&C: plates move apart
é faulting occurs, causes earthquake
é no new crust form
é formation of new sea (e.g. red sea)
é magma flows up cracks in crust
é volcanoes formed
Convergent (O&O):plates edges bent into deep oceanic trench [e.g. Marianas Trench in Pacific Ocean (Pacific plate dives below Philippines)]
é plate with lower percentage of continental crust would subduct
é subduction zone, subducting plate melts under high heat and friction
é silica-rich magma produced
é form chain of subduction volcanoes- island arc
é earthquake occurs: downward movement of subducting plate is not smooth
O&C: thinner and denser oceanic plate subducts
é long, narrow and deep oceanic trench is formed (e.g. Peru-Chile Trench off South American coast)
é faulting occurs, earthquake occurs
é downwards movement of plate not smooth
é subducting plate melts under high heat and friction, silica-rich magma formed
é being less dense, magma rises up fractures
é escapes through vents to the land surface
é forms subduction volcanoes
é continental late contorted and folded
é form fold mountains
C&C: no subduction
é one may be pushed under the other for a short distance
é both light and buoyant, no volcanic activity
é folding occurs, produce great uplift and highly contorted fold mountain ranges
é e.g. Himalayan Mountains (Indo-Australian and Eurasian)
é faulting and earthquakes
Transform: same direction @ diff speeds
é Pacific Plate and North American plate along the San Andreas Fault
é lithospheric material neither created not destroyed
é plates moving in different directions
é jerky movements causes earthquakes
é no volcanic activity
fold mountains: fold is a bend in rock strata
anticline: hill syncline: valley
folds: 1. simple fold: limbs with same steepness
2. asymmetrical fold: uneven limbs, uneven forces
3. overfold: both limbs sloping in same direction
4. recumbent fold: axis of fold is almost horizontal
5. overthrust fold: fractured recumbent fold
Circum pacific region: rocky mtns & andes, island arcs (japan & the philippines)
Eurasion Indonesian belt: atlas mtns Africa; alps southern Europe; Himalayas northern India
Himalayas mtns: indo-australian & Eurasian plates
-tethys sea separating India & asia subducted under Eurasian plate
-when asia & India continental mass met, folding of sediments occurred as there was no subduction
Andes mtns: nazca & south American plates
-oceanic nazca sinks under continental SA plate, being thinner and denser
-sediment on the ocean floor squeezed & crumpled
-silica rich magma rose thru fractures: subduction vol
Faulting: break or fracture in rocks where they are displaced. caused by stresses & strains
1. normal fault: tension; lithosphere is pulled apart
- one blocked lowered; forms steep scarp/cliff
2. reverse fault: compression; one block rises, forms overhanging escarpment which may be eroded
3. transform fault: adjacent blocks slide past horizontally along the fracture
Horst(block mtn): uplifted block w/ steep fault scarps
-caused by tension or compression
Tilt block: block mtn w one scarp
Rift valley/graben: elongated deep valley
-caused by tension or compression
-parallel faults form stepped scarps
-magma rises to form rift volcanoes at sides
Lava: lower silica content >higher temperature & more fluid
Basic: low silica content, fluid, rich in iron & magnesium, hot abt 1200oC, flows slowly & far
-produced at constructive boundaries
-quiet explosion as it allows expanding gases to escape easily thru the vent
-forms gently sloping volcanoes 2o-10o
Acid: high silica content, viscous, not so hot 800oC, solidifies quickly, does not flow far
-produced at destructive boundaries
-violent explosion as lava solidifies quickly & blocks the upward movement of expanding gases
-forms steep sided volcanoes
Lava plateau: built up by basaltic lava frm fissures
-spread ovr large area, solidifies: Columbia plateau
Volcano: 1. conical or dome shaped
2. crater: throws out gases, pyroclasts & lava
-enlarged crater (>1kmD) caldera; may contain lake
-caldera formed when removal of magma is faster than it can be replenished so summit collapses into magma chamber of volcano
3. magma flows frm magma chamber to pipe to vent
4. composite volcano may have a secondary cone
Active: erupts frequently & in recent times
Dormant: not erupted recently but not extinct
Extinct: does not erupt anymore
Formation: magma rises up fractures in rocks; pressure is reduced when it moves upwards: allows gases to expand & volcanic material to be ejected
-volcanic material piles up arnd vent, forms volcano
Gases: steam, carbon dioxide, sulphur dioxide
Solids: ash, dust, volcanic bombs, cinder (pyroclasts)
types: 1. ash & cinder volcano: steep sided, gentle base symmetrical; formed frm hot ash & red hot cinders; bowl shaped summit crater
2. basic lava volcano(shield):wide base gentle slopes
Hot spot volcanoes: mauna loa in Hawaii
-far away frm plate boundary
Basaltic magma issues thru a vent to form volcano
-plate moves, chain of volcanic islands formed
3. lava dome: acid lava too viscous & solidifies ovr vent to form a bulbous structure. Sides become steep and dome shaped when lava fills up the interior
4. volcanic plug: viscous acid lava solidified in central pipe and forms a spine or volcanic plug
5. composite volcano: alternate layers of pyroclasts & viscous acid lava; steeper towards top, gentler at base – composite cones formed when lava flows out of secondary pipes
6. minor features associated with vulcanicity
a. volcanic hot spring
b. geyser: violent ejection of hot water
problems: 1. massive destruction: of lives & property; interrupt communication; gases (CO2) suffocate ppl
2. tsunamis: eruptions near coast create huge waves
3. pollution: damage respiratory systems; contaminate water sources
4. steam affects rain; sulphur affects ozone layer
Benefits: 1. weathered volcanic materials make good fertile soil with necessary minerals for cultivation
2. precious stones & minerals: mining
3. tourism: hot springs resorts, attractions
4. geothermal energy (heat below earth’s surface): produce electricity, warm houses
Earthquakes: occurs when energy built up in earth’s crust is suddenly released
-occurs when convergent movement is not smooth
-stress in rocks so great that causes the ground to vibrate when the rocks jerk free
1. focus: source of earthquake
2. epicentre: point on surface directly above focus
3. seismic waves: measured by seismograph
4. Richter scale0-9: measure amt of energy released
Problems: 1. destroy buildings & roads : toppled over, hinders rescue work
2. disrupts water, gas & electricity supplies & communication: burst pipes, broken telephone lines; fires formed, diseases rampant -water contaminated
3. causes landslides & tsunamis
Factors affecting extent of damage: 1. magnitude
2. depth of focus: shallow focus, large extent
3. epicentre: nearer, larger damage; more solid rock epicentre, less damage
4. constructions: dense built up buildings, more damage; flimsy old building cannot withstand
5. forecast: prediction & preparation help
6. tsunamis: no tsunami, less damage
Ways to reduce damage: 1. location, design & materials of buildings: don’t build on active fault zone;unstable soil, use shock absorbing rubber blocks
2. limit outbreak of fires: use fireproof materials
3. conduct drills; preparation: familiarise people with emergency procedures; have enough supplies
4. prediction & warning systems
Friday, September 23, 2005
GEOG - CLIMATE & NATURAL VEGETATION
Equatorial climate: btwn 10oN &10oS
1.temperature: high, abt 27oC; small range of 3oC
-due to angle of incidence and thick cloud cover
2. humidity: high, thick cloud cover
3. rainfall: high, 2000mm/yr, no distinct dry season
Tropical rainforest
1. dense & luxuriant vegetation, multiple species: hot and wet climate encourages rapid plant growth
a. emergent layer >30m: struggle for light, buttress roots for supporting heavy weight of trees
b. canopy layer 20-30m: crowns form continuous canopy, prevents sunlight from reaching forest floor
c. understorey layer 5-15m: narrow crowns (oval)
d. shrub layer: shrubs, ferns and small young trees
e. undergrowth layer: sparse as little sunlight reaches the forest floor due to canopy; mostly small plants, ferns & saprophytes that live on dead organic matter à fast decomposition, little leaf litter
2. evergreen tress: climate allows continuous growth
3. smooth and waxy thick leathery leaves with pointing drip tips: allow rain to run off easily; withstand the heat (high rainfall & temperature)
4. thin barks: no need for protection frm cold
5. branches found on top one third of tree: to obtain maximum sunlight for photosynthesis
6. shallow roots: absorb water and nutrients quickly
-high rainfall and decomposition rate
Mangrove forest: near the tropics- peninsular m’sia
Climate: salty & brackish water; muddy, water logged soil with little oxygen
1. specialised roots to breathe in air during low tide
a. bruguiera zone (furthest frm sea): knee like roots
b. rhizophora zone: prop roots to anchor in mud
c. avicennia/sonneratia zone: pencil like roots
2. broad leathery leaves with drip tips: allow rain to flow off quickly; reduce excessive transpiration
3. special salt glands: excrete excess salt (eg. frm excessive transpiration) or store salt in old leaves
Tropical monsoon climate: 10oN-25oN, 10oS-25oS
temperature: larger annual range 5o-17o; 30oC or higher in hot season, <20o-24oC in cooler months
rainfall: distinct dry season; >2000mm/yr
Tropical monsoon forest
1. not as dense as & has fewer species than tropical rainforest: due to lower rainfall & harsher conditions
a. canopy layer 25-30m: no continuous canopy
b. understorey layer abt 15m
c. ground layer: dense with thick shrubs and herbs
-due to sunlight reaching forest floor
2. deciduous trees: shed leaves during a particular period annually to reduce loss of water through transpiration (seasonal rainfall)
3. waxy broad thick leaves with leathery texture: to withstand heat & remove water during rainy season
4. thick and coarse bark: adapt to dry conditions
5. branches not as high: less struggle for sunlight
6. deep roots: get water during dry season
Temperate deciduous forest: 40oN-60oN & south
Climate: rainfall: 600-1000mm; cool summers & mild winters; 6-8 growing months
1. less dense & fewer species than tropical rainforest
a. canopy layer~30m: oak, elm, ash, beech, chestnut
b. sub canopy: young saplings, shrubs, short trees
c. shrub layer: non woody plants that grow rapidly during warmer months when there is more sunlight
d. ground layer: mosses & lichens
2. deciduous: shed leaves in autumn to conserve energy and stop growth in winter
3. broad leaves: trap as much sunlight as possible
4. thick bark: protection in winter
5. deep roots: obtain nutrients & water when top surface of water is frozen
6. cell sap increase in winter: increased concentration gradient, can absorb more water through osmosis
Coniferous forest: 60oN-70oN ,also found on high mountains at lower latitudes
Climate: long cold winters (oct-apr), short & cool summers; brief growing season; temp can fall to -30oC or less; low annual precipitation (mostly snow)
1a. few species: larch, fir, pine, spruce (softwoods)
b. uniform height: 20-25m, large trees 40m
c. little undergrowth: mosses & lichens
-due to poor soil and insufficient sunlight
2. evergreen: photosynthesise as soon as conditions allow (>6oC), grow in spring when sun melts snow
3. needle like small leaves with thick cuticles: reduce transpiration in strong winds
4. thick barks: protection against extreme cold
5. long roots for anchorage; shallow roots as cold boulder soil does not allow deep root growth
6. cone shaped trees with downward sloping branches: allow snow to slide off w/o breaking
7. cones protect seeds during very cold winters
:))) - lala
1.temperature: high, abt 27oC; small range of 3oC
-due to angle of incidence and thick cloud cover
2. humidity: high, thick cloud cover
3. rainfall: high, 2000mm/yr, no distinct dry season
Tropical rainforest
1. dense & luxuriant vegetation, multiple species: hot and wet climate encourages rapid plant growth
a. emergent layer >30m: struggle for light, buttress roots for supporting heavy weight of trees
b. canopy layer 20-30m: crowns form continuous canopy, prevents sunlight from reaching forest floor
c. understorey layer 5-15m: narrow crowns (oval)
d. shrub layer: shrubs, ferns and small young trees
e. undergrowth layer: sparse as little sunlight reaches the forest floor due to canopy; mostly small plants, ferns & saprophytes that live on dead organic matter à fast decomposition, little leaf litter
2. evergreen tress: climate allows continuous growth
3. smooth and waxy thick leathery leaves with pointing drip tips: allow rain to run off easily; withstand the heat (high rainfall & temperature)
4. thin barks: no need for protection frm cold
5. branches found on top one third of tree: to obtain maximum sunlight for photosynthesis
6. shallow roots: absorb water and nutrients quickly
-high rainfall and decomposition rate
Mangrove forest: near the tropics- peninsular m’sia
Climate: salty & brackish water; muddy, water logged soil with little oxygen
1. specialised roots to breathe in air during low tide
a. bruguiera zone (furthest frm sea): knee like roots
b. rhizophora zone: prop roots to anchor in mud
c. avicennia/sonneratia zone: pencil like roots
2. broad leathery leaves with drip tips: allow rain to flow off quickly; reduce excessive transpiration
3. special salt glands: excrete excess salt (eg. frm excessive transpiration) or store salt in old leaves
Tropical monsoon climate: 10oN-25oN, 10oS-25oS
temperature: larger annual range 5o-17o; 30oC or higher in hot season, <20o-24oC in cooler months
rainfall: distinct dry season; >2000mm/yr
Tropical monsoon forest
1. not as dense as & has fewer species than tropical rainforest: due to lower rainfall & harsher conditions
a. canopy layer 25-30m: no continuous canopy
b. understorey layer abt 15m
c. ground layer: dense with thick shrubs and herbs
-due to sunlight reaching forest floor
2. deciduous trees: shed leaves during a particular period annually to reduce loss of water through transpiration (seasonal rainfall)
3. waxy broad thick leaves with leathery texture: to withstand heat & remove water during rainy season
4. thick and coarse bark: adapt to dry conditions
5. branches not as high: less struggle for sunlight
6. deep roots: get water during dry season
Temperate deciduous forest: 40oN-60oN & south
Climate: rainfall: 600-1000mm; cool summers & mild winters; 6-8 growing months
1. less dense & fewer species than tropical rainforest
a. canopy layer~30m: oak, elm, ash, beech, chestnut
b. sub canopy: young saplings, shrubs, short trees
c. shrub layer: non woody plants that grow rapidly during warmer months when there is more sunlight
d. ground layer: mosses & lichens
2. deciduous: shed leaves in autumn to conserve energy and stop growth in winter
3. broad leaves: trap as much sunlight as possible
4. thick bark: protection in winter
5. deep roots: obtain nutrients & water when top surface of water is frozen
6. cell sap increase in winter: increased concentration gradient, can absorb more water through osmosis
Coniferous forest: 60oN-70oN ,also found on high mountains at lower latitudes
Climate: long cold winters (oct-apr), short & cool summers; brief growing season; temp can fall to -30oC or less; low annual precipitation (mostly snow)
1a. few species: larch, fir, pine, spruce (softwoods)
b. uniform height: 20-25m, large trees 40m
c. little undergrowth: mosses & lichens
-due to poor soil and insufficient sunlight
2. evergreen: photosynthesise as soon as conditions allow (>6oC), grow in spring when sun melts snow
3. needle like small leaves with thick cuticles: reduce transpiration in strong winds
4. thick barks: protection against extreme cold
5. long roots for anchorage; shallow roots as cold boulder soil does not allow deep root growth
6. cone shaped trees with downward sloping branches: allow snow to slide off w/o breaking
7. cones protect seeds during very cold winters
:))) - lala
GEOG - WEATHER STUDIES
Temperature: degree of heat or cold
Factors affecting temperature:
1. altitude: normal lapse rate 6.4oC per 1000m
2. latitude: angle of incidence
3. aspect: affects temperature regions
4. land surface: vegetation cooler than concrete
5. ocean currents: N Alantic drift warm oyashio cold
6. distance from sea: maritime/continental influence
7. humidity: high>more cloud cover
Instrument: Six’s thermometer
U bend – mercury
Upper limbs – alcohol
Right bulb with vacuum
Humidity: state of atmosphere(water vapour content)
Depends on temperature: warmer air holds more
Saturated: holds max amt at a particular temp
Relative humidity: percentage of amt it holds against total amt it can hold
Instrument: hygrometer (wet + dry bulb thermometer)
Wet: wrapped w muslin kept moist w distilled water
Wet bulb depression: more w less humidity
Stevenson screen hygrometer, six’s thermometer
painted white
more than 1m above ground
wooden
louvered sides
sited in open area with short grass
Rainfall
1. convectional: accompanied by lightning & thunder
-high humidity & temp, tropical areas, temperature regions in summer
-heat from ground warms up air which rises
-heavy rain, short period, falls in afternoon
2. relief: moist onshore air forced upwards
-windward & leeward sides
3. frontal: when 2 masses of air with different masses, temperatures and densities meet
a. cold front: cold air slips under warm air
-warm air forced upwards
-heavy rain, short period, small area
b. warm front: warm air rises gently
-gentle rain, long period, wide area
Instrument: rain gauge: outer & inner copper casing, glass bottle, funnel with tapering end
1. open area: rain can enter from any angle, prevent dripping, blockage of opening by leaves
2. sunk into grassy ground (one third below ground): cooler, prevent toppling & splashing
_read evry 12h in mm, poured in measuring cylinder
_small opening to minimise evaporation
Anemometer: 3 or 4 cups joined to the ends of metal rods fixed to a spindle
-sited 10m above ground in open area
Wind vane: freely moving pointer on a vertical shaft
-shows direction which the wind is blowing from
-sited 10m above ground away from obstruction
Air pressure: air pressure higher nearer ground & decreases with height
warm air expands, rises,results in low pressure below
cold air sinks, exerts high pressure below it
Instrument: barometer (aneroid)
Metal box that is a partial vacuum, flexible corrugated top that moves according to change in pressure. The pressure is read off a calibrated dial
Planetary pressure system
1. doldrums(equatorial low pressure belt) 5oN to 5oS
-caused by high temperatures (warmed air rises)
2. sub-tropical high (horse latitudes) 30oN and 30oS
-air frm doldrums move up and cools, sinks
3. sub-polar low pressure belts 60oN and 60oS
-polar & sub-tropical winds converge, forced to rise
4. polar high pressure belts 90oN and 90oS
-due to low temperatures (cooled air sinks)
Planetary wind system Coriolis effect: deflection
Winds move frm high pressure to low pressure areas
-deflected to right in northern hemisphere
-deflected to left in southern hemisphere
1. trade winds: blow from sub-tropical to doldrums
North hemi: deflected to right, north-east trades
South hemi: deflected to left, south-east trades
intertropical convergence zone: converge at equator
2. westerlies: blow frm sub tropical to sub polar
North hemi: deflected to right, south westerlies
South hemi: deflected to left, north westerlies
3. easterlies: blow frm polar to sub polar
North hemi: deflected to right, north easterlies
South hemi: deflected to left, south easterlies
Sea and land breezes: small scale local winds
-due to diff rates of heating up and cooling down
Day: land hotter, lower pressure, sea breeze to land
Ngt: land cooler, higher pressure, land breeze to sea
Monsoons: large scale seasonal winds
-due to diff rates of the large land masses
End & beginning of yr: sun overhead near tropic of Capricorn; north hemi have winter, south hemi have summer; winds arrive in north china & japan as north west monsoon and as north east monsoon in south china n SEA; wind deflected to left in south hemi, arrive in australia & indonesia as north west monsoon
Middle of yr: sun overhead near tropic of cancer; north hemi have summer, south hemi have winter; wind deflected to right in north hemi, arrives in SEA as south west monsoon, south east monsoon in japan & north china, south west in india
yay! undetailedness :))) - lala
Factors affecting temperature:
1. altitude: normal lapse rate 6.4oC per 1000m
2. latitude: angle of incidence
3. aspect: affects temperature regions
4. land surface: vegetation cooler than concrete
5. ocean currents: N Alantic drift warm oyashio cold
6. distance from sea: maritime/continental influence
7. humidity: high>more cloud cover
Instrument: Six’s thermometer
U bend – mercury
Upper limbs – alcohol
Right bulb with vacuum
Humidity: state of atmosphere(water vapour content)
Depends on temperature: warmer air holds more
Saturated: holds max amt at a particular temp
Relative humidity: percentage of amt it holds against total amt it can hold
Instrument: hygrometer (wet + dry bulb thermometer)
Wet: wrapped w muslin kept moist w distilled water
Wet bulb depression: more w less humidity
Stevenson screen hygrometer, six’s thermometer
painted white
more than 1m above ground
wooden
louvered sides
sited in open area with short grass
Rainfall
1. convectional: accompanied by lightning & thunder
-high humidity & temp, tropical areas, temperature regions in summer
-heat from ground warms up air which rises
-heavy rain, short period, falls in afternoon
2. relief: moist onshore air forced upwards
-windward & leeward sides
3. frontal: when 2 masses of air with different masses, temperatures and densities meet
a. cold front: cold air slips under warm air
-warm air forced upwards
-heavy rain, short period, small area
b. warm front: warm air rises gently
-gentle rain, long period, wide area
Instrument: rain gauge: outer & inner copper casing, glass bottle, funnel with tapering end
1. open area: rain can enter from any angle, prevent dripping, blockage of opening by leaves
2. sunk into grassy ground (one third below ground): cooler, prevent toppling & splashing
_read evry 12h in mm, poured in measuring cylinder
_small opening to minimise evaporation
Anemometer: 3 or 4 cups joined to the ends of metal rods fixed to a spindle
-sited 10m above ground in open area
Wind vane: freely moving pointer on a vertical shaft
-shows direction which the wind is blowing from
-sited 10m above ground away from obstruction
Air pressure: air pressure higher nearer ground & decreases with height
warm air expands, rises,results in low pressure below
cold air sinks, exerts high pressure below it
Instrument: barometer (aneroid)
Metal box that is a partial vacuum, flexible corrugated top that moves according to change in pressure. The pressure is read off a calibrated dial
Planetary pressure system
1. doldrums(equatorial low pressure belt) 5oN to 5oS
-caused by high temperatures (warmed air rises)
2. sub-tropical high (horse latitudes) 30oN and 30oS
-air frm doldrums move up and cools, sinks
3. sub-polar low pressure belts 60oN and 60oS
-polar & sub-tropical winds converge, forced to rise
4. polar high pressure belts 90oN and 90oS
-due to low temperatures (cooled air sinks)
Planetary wind system Coriolis effect: deflection
Winds move frm high pressure to low pressure areas
-deflected to right in northern hemisphere
-deflected to left in southern hemisphere
1. trade winds: blow from sub-tropical to doldrums
North hemi: deflected to right, north-east trades
South hemi: deflected to left, south-east trades
intertropical convergence zone: converge at equator
2. westerlies: blow frm sub tropical to sub polar
North hemi: deflected to right, south westerlies
South hemi: deflected to left, north westerlies
3. easterlies: blow frm polar to sub polar
North hemi: deflected to right, north easterlies
South hemi: deflected to left, south easterlies
Sea and land breezes: small scale local winds
-due to diff rates of heating up and cooling down
Day: land hotter, lower pressure, sea breeze to land
Ngt: land cooler, higher pressure, land breeze to sea
Monsoons: large scale seasonal winds
-due to diff rates of the large land masses
End & beginning of yr: sun overhead near tropic of Capricorn; north hemi have winter, south hemi have summer; winds arrive in north china & japan as north west monsoon and as north east monsoon in south china n SEA; wind deflected to left in south hemi, arrive in australia & indonesia as north west monsoon
Middle of yr: sun overhead near tropic of cancer; north hemi have summer, south hemi have winter; wind deflected to right in north hemi, arrives in SEA as south west monsoon, south east monsoon in japan & north china, south west in india
yay! undetailedness :))) - lala
SS - EDUCATION IN SINGAPORE
+meeting the needs of a young nation
_rapidly growing population
_not enough schools and places for every child
>schools were built to meet the demand
+building national loyalty
_english medium schools were not popular as the people had the freedom to choose the language of instruction
_pupils of different races seldom met
_could not achieve national loyalty and social cohesion
_difficulties to nation building
>implemented daily flag raising and pledge taking ceremony
+fostering social cohesion
_to show that the government was fair to all races
>textbooks loaned to needy pupils from all language streams
>all government schools provided with same physical facilities
>all pri sch pupils sit for common exam (PSLE)
_encouraged interaction between pupils and teachers of different language streams
_promote racial harmony
>integrated school system – same class held in different languages
_bilingualism made compulsory (1966)
>english as link language – break down social barriers, build more harmonious society
>mother tongue to impart moral values and cultural traditions of each race
_emphasised on uniformed groups ECA/CCA such as National (Police) Cadet Corps
>provided pupils with opportunities for interaction and healthy competition
>instilled loyalty
>bring pupils of different race together
+preparing for economic development
_serious unemployment in 1960s due to declining entrepot trade
>moved to manufacturing
_technical education and new courses introduced to schools (1969), more technical schools were set up
>provide young workforce with relevant skills to meet the needs of the changing economy
+improving the quality of education
_bilingual policy ineffective
_education system failed to consider different learning needs of different pupils
+streaming
_introduced to cater to the different abilities and learning paces of pupils
>channelled to different streams according to performance in languages and mathematics
>GEP to provide more challenging education
>N(T) to provide technically orientated curriculum
+teaching moral values
_introduce Moral Education programme
>to inculcate in pupils a common set of desirable moral values such a s social responsibility and loyalty to the country
_introduce Religious Knowledge (1982)
>reinforce values taught in moral education
_made not compulsory (1990)
>it encouraged conversion of the religious beliefs taught even though the government should be neutral and not promote religions in schools
_replaced by Civics and Moral Education (1992)
>captures essence of being a Singaporean
>preserves cultural heritage of the communities
>Shared Values help to develop Singaporean identity - includes elements of Singapore’s cultures and the attitudes and values that have helped her survival and success as a nation
+encouraging creativity
_global recession(1981) slowed down international trade and Singapore’s high economic growth
>Singaporeans had to be creative and innovative to adapt to and initiate changes that would revive the economy and stimulate economic growth
_schools given more freedom
>autonomous and independent schools
- freedom to cater to specific needs
+preparing for the challenges of the 21st century
_have to be resourceful and self reliant to thrive in competitive global economy
+promoting critical and creative thinking
_project work to encourage pupils to think creatively and critically
+using information technology (IT)
_use of IT in teaching and learning in schools
+introducing National Education (1997)
_celebrations of events such as Racial Harmony and Total Defence Day
>understand how Singapore survived difficult times
>foster strong bonds, more emotionally attached
_Community Involvement Programme (1998)
>nurture pupils into good citizens conscious of their responsibility to family, society and country
+developing talents
>school programmes to cater to pupils’ diverse talents
>provide them with opportunities
+compulsory primary school education (2003)
_emphasis on life long learning
>each child will have at least a common core of knowledge and skills to prepare them for employment
_achieve national identity and social cohesion
LOOKING BACK
education policies reviewed constantly to develop potential of each citizen/student fully
hahaha so undetailed :) -lala
_rapidly growing population
_not enough schools and places for every child
>schools were built to meet the demand
+building national loyalty
_english medium schools were not popular as the people had the freedom to choose the language of instruction
_pupils of different races seldom met
_could not achieve national loyalty and social cohesion
_difficulties to nation building
>implemented daily flag raising and pledge taking ceremony
+fostering social cohesion
_to show that the government was fair to all races
>textbooks loaned to needy pupils from all language streams
>all government schools provided with same physical facilities
>all pri sch pupils sit for common exam (PSLE)
_encouraged interaction between pupils and teachers of different language streams
_promote racial harmony
>integrated school system – same class held in different languages
_bilingualism made compulsory (1966)
>english as link language – break down social barriers, build more harmonious society
>mother tongue to impart moral values and cultural traditions of each race
_emphasised on uniformed groups ECA/CCA such as National (Police) Cadet Corps
>provided pupils with opportunities for interaction and healthy competition
>instilled loyalty
>bring pupils of different race together
+preparing for economic development
_serious unemployment in 1960s due to declining entrepot trade
>moved to manufacturing
_technical education and new courses introduced to schools (1969), more technical schools were set up
>provide young workforce with relevant skills to meet the needs of the changing economy
+improving the quality of education
_bilingual policy ineffective
_education system failed to consider different learning needs of different pupils
+streaming
_introduced to cater to the different abilities and learning paces of pupils
>channelled to different streams according to performance in languages and mathematics
>GEP to provide more challenging education
>N(T) to provide technically orientated curriculum
+teaching moral values
_introduce Moral Education programme
>to inculcate in pupils a common set of desirable moral values such a s social responsibility and loyalty to the country
_introduce Religious Knowledge (1982)
>reinforce values taught in moral education
_made not compulsory (1990)
>it encouraged conversion of the religious beliefs taught even though the government should be neutral and not promote religions in schools
_replaced by Civics and Moral Education (1992)
>captures essence of being a Singaporean
>preserves cultural heritage of the communities
>Shared Values help to develop Singaporean identity - includes elements of Singapore’s cultures and the attitudes and values that have helped her survival and success as a nation
+encouraging creativity
_global recession(1981) slowed down international trade and Singapore’s high economic growth
>Singaporeans had to be creative and innovative to adapt to and initiate changes that would revive the economy and stimulate economic growth
_schools given more freedom
>autonomous and independent schools
- freedom to cater to specific needs
+preparing for the challenges of the 21st century
_have to be resourceful and self reliant to thrive in competitive global economy
+promoting critical and creative thinking
_project work to encourage pupils to think creatively and critically
+using information technology (IT)
_use of IT in teaching and learning in schools
+introducing National Education (1997)
_celebrations of events such as Racial Harmony and Total Defence Day
>understand how Singapore survived difficult times
>foster strong bonds, more emotionally attached
_Community Involvement Programme (1998)
>nurture pupils into good citizens conscious of their responsibility to family, society and country
+developing talents
>school programmes to cater to pupils’ diverse talents
>provide them with opportunities
+compulsory primary school education (2003)
_emphasis on life long learning
>each child will have at least a common core of knowledge and skills to prepare them for employment
_achieve national identity and social cohesion
LOOKING BACK
education policies reviewed constantly to develop potential of each citizen/student fully
hahaha so undetailed :) -lala
