Wednesday, October 1, 2008
CLIFF!
Cliffs are formed when water flows through a steep rock surface. Hydraulic action and abrasion are the main cause of erosion of the rocks by undercutting to form a notch. As undercutting continues, it will deepen to form a cave, which might then deepen further and cause the overhanging cave to collapse. As overhanging cave collapse, the debris form will accumulate at the base and will either be washed away by the sea water or carried away by the crashing waves. As this continues, a cliff is formed and a platform at the bottom of the cliff will also form known as the wave-cut platform.
COAST! (:
Coast is the part that merges and adjoins with the sea.
Wave is the movement of the water surface of the sea and is driven by wind.
The size of waves affected by 3 factors:
1) Fetch: The longer the fetch, bigger the waves formed
2) Wind movement: Bigger wind movement, bigger the waves
3) Wind duration: The long the duration of wind, the larger the waves.
-> Water that flows in deep water will lose energy
-> Water that flows near to shore will slow down due to friction
-> Friction will cause waves to rise and bend
-> As it continues bending, it will bend and form foams.
Constructive Wave Destructive Wave
Long wave length Short wavelength
Short wave height Long wavelength
wave frequency of 6-8 wave frequency of 10-14
spilling beaker plunging beaker
Happens in sheltered and gentle coast Happens in open and steep coast
Erosion is most prominent Deposition most prominent
Tides are the daily alternate rising and falling of sea level due to gravitational pull on the moon, and to a certain extent, the sun.
It has an impact on the coast: During high tide, erosion of the coast occurs and on low tide, it will transport large part of the coast away.
Currents are large-scale, persistent movements of the water, largely driven by prevailing wind.
They are responsible for shaping the coast and thus is able to transport a huge area of coast over a long distance in a short period of time.
Longshore currents are currents that are formed when waves approach the coast at an oblique angle, and is parallel to the coast.
Coastal Erosion is affected by 4 factors:
-> Type of wave: Usually destructive; more energy for erosion
-> Minerals and composition of rocks; Those with more lines of weaknesses will get eroded
first as compared to lesser ones. Softer rocks will get eroded faster than hard rocks; Those
with dissolve minerals will erode away faster ; usually in open and steep coast.
Coastal Deposition is affected by 3 factors:
Gradient: Gentle gradient
Sediments: Speed of coast is slow and a lot of sediments there and so it will settle down on
bed of coast and get deposited.
Position of coast: gentle and sheltered coast
Coastal Transportation: By Longshore drift
-> Waves that approach the coast at an obique angle and are parallel to coast
-> Sediments are transported to the shore by swash
-> Sediments will then be pulled back by backwash that moves perpendicular to the shore.
Wave is the movement of the water surface of the sea and is driven by wind.
The size of waves affected by 3 factors:
1) Fetch: The longer the fetch, bigger the waves formed
2) Wind movement: Bigger wind movement, bigger the waves
3) Wind duration: The long the duration of wind, the larger the waves.
-> Water that flows in deep water will lose energy
-> Water that flows near to shore will slow down due to friction
-> Friction will cause waves to rise and bend
-> As it continues bending, it will bend and form foams.
Constructive Wave Destructive Wave
Long wave length Short wavelength
Short wave height Long wavelength
wave frequency of 6-8 wave frequency of 10-14
spilling beaker plunging beaker
Happens in sheltered and gentle coast Happens in open and steep coast
Erosion is most prominent Deposition most prominent
Tides are the daily alternate rising and falling of sea level due to gravitational pull on the moon, and to a certain extent, the sun.
It has an impact on the coast: During high tide, erosion of the coast occurs and on low tide, it will transport large part of the coast away.
Currents are large-scale, persistent movements of the water, largely driven by prevailing wind.
They are responsible for shaping the coast and thus is able to transport a huge area of coast over a long distance in a short period of time.
Longshore currents are currents that are formed when waves approach the coast at an oblique angle, and is parallel to the coast.
Coastal Erosion is affected by 4 factors:
-> Type of wave: Usually destructive; more energy for erosion
-> Minerals and composition of rocks; Those with more lines of weaknesses will get eroded
first as compared to lesser ones. Softer rocks will get eroded faster than hard rocks; Those
with dissolve minerals will erode away faster ; usually in open and steep coast.
Coastal Deposition is affected by 3 factors:
Gradient: Gentle gradient
Sediments: Speed of coast is slow and a lot of sediments there and so it will settle down on
bed of coast and get deposited.
Position of coast: gentle and sheltered coast
Coastal Transportation: By Longshore drift
-> Waves that approach the coast at an obique angle and are parallel to coast
-> Sediments are transported to the shore by swash
-> Sediments will then be pulled back by backwash that moves perpendicular to the shore.
Let's Compare!
Hmm.. Lets all compare between the management of rivers and coast.
Rivers:
River channelisation rivers to the different methods and strategies to manage the river so as to prevent it from reaching flood height.
1) River alignment
- Refers to the altering of the river course so as to reduce the chances of erosion from taking
place.
- Can be done by removing large boulders from river channel and also deepening and widening
of the river through dredging.
- Examples where this is carried out is in Kallang and Singapore River
2) River re-sectioning
- Refers to the re-sectioning of a river which can be done by shortening the river
- Example of it is the Mississippi River that has been shortened by 240km to reduce the threat
of flooding
3) Vegetable Planting and Clearing
- By planting vegetable, it is to slow down speed of flow by reducing surface runoff to the
river channel and this has negative impacts which are adding weight to bank stress which
might eventually lead to the collapse of the bank and also debris from plants to increase
rate if erosion in different parts of the river.
- By clearing vegetable, it is to increase rate of flow as there will be more surface runoff.
This is to decrease the chances of flooding to occur. However, it is a viable option.
4) Bank Protection
- Building banks, levees and embankments to protect the banks and prevent it from collapsing
during heavy downpour.
Coast:
It is important to manage coast as it will ensure that development is properly planned and managed to prevent damage of coast by erosion.
Hard engineering approach that involves building of physical structures do as to defend against erosive power of waves.
1) Seawall
- Build along coast and is made of either concrete, wood or rock
- They help to absorb high energy waves before they erode away loose beach materials
Negative Impact:
It is unable to prevent powerful backwash from washing away beach materials beneathe the walls and so will cause undermining of the base of the walls and cause collapse and $$
2) Breakwaters
- To protect coast and harbour
- They are able to absorb energy waves before they reach the coast
- Can either be build with one end attached to land or be offshore
- If it is offshore, it will form a calm zone of water behind it.
- Deposition of load occurs behind it
Negative impact:
Only water behind the coast is protected, but those away will be unprotected and cause erosion at other parts of the coast.
3) Groynes
- Built at right angles to coast
- Prevent longshore drift
- Help to absorb and reduce wave energy only at side of groyne facing longshore drift but not
at downdrift and so erosion occurs there
- To prevent erosion, groynes is angled at 5-10 degrees frm coast
Negative Impact
Erosion will still occur at other parts of the coast
4) Gabions
-Wired cages filled with crushed rocks
- Help to reduce erosion by reducing energy waves
Negative Impact
Only short term protection of 5-10 years
A lot of regular maintainence needed (corrode by seawater, excessive trampling, vandalism)
Very costly
Soft engineering measure which does not involve building of any physical structure buut focusses on planning and managing coastal areas and properties to prevent it from getting damaged by erosion.
1) Beach Nourishment
- Involves the replenishing of sand so as to increase beach quality and storm protection.
Negative impact:
Very expensive
Destroy natural habitat: Sand that is washed into sea will cover the coral reefs and prevent them from getting sunlight to survive.
2) Relocation of Property
- Green Line policy to restrict building of houses near to coastal regions where flooding might
occur
Positive impact:
A very useful policy as global warming is causing an increases in sea level and so it will help to prevent chances of building being affected
3) Planting of Mangroves
- Mangroves have prop, long, curved roots that prop up to trap sediments
- New anchorage of roots will cause the plant to trap enough sediments to form island
- It will be extending outwards to the sea
Negative impacts
Some coast cannot take the stress of the mangroves as they are affected by destructive waves
The depth of the coast with plants will be shallower and so hinders maritime trade
4) Stabilising Dunes
- Happens in places with large amts of sand and strong wind
- Wind will blow sand further inland
- Sand will pile up to form coastal dunes (Protect coast from sea)
- They are fragile and shrubs struggle to hold them in place
5) Coral Reefs
- Coral reefs help to reduce wavee energy in water
- If they die, then the waters will move at full force and cause erosion to take place
- Can be made artificially by using environmental materials and put in sea bed
- Help to enhance fishing opportunities and act as undersea barrier to reduce chances of
erosion.
Rivers:
River channelisation rivers to the different methods and strategies to manage the river so as to prevent it from reaching flood height.
1) River alignment
- Refers to the altering of the river course so as to reduce the chances of erosion from taking
place.
- Can be done by removing large boulders from river channel and also deepening and widening
of the river through dredging.
- Examples where this is carried out is in Kallang and Singapore River
2) River re-sectioning
- Refers to the re-sectioning of a river which can be done by shortening the river
- Example of it is the Mississippi River that has been shortened by 240km to reduce the threat
of flooding
3) Vegetable Planting and Clearing
- By planting vegetable, it is to slow down speed of flow by reducing surface runoff to the
river channel and this has negative impacts which are adding weight to bank stress which
might eventually lead to the collapse of the bank and also debris from plants to increase
rate if erosion in different parts of the river.
- By clearing vegetable, it is to increase rate of flow as there will be more surface runoff.
This is to decrease the chances of flooding to occur. However, it is a viable option.
4) Bank Protection
- Building banks, levees and embankments to protect the banks and prevent it from collapsing
during heavy downpour.
Coast:
It is important to manage coast as it will ensure that development is properly planned and managed to prevent damage of coast by erosion.
Hard engineering approach that involves building of physical structures do as to defend against erosive power of waves.
1) Seawall
- Build along coast and is made of either concrete, wood or rock
- They help to absorb high energy waves before they erode away loose beach materials
Negative Impact:
It is unable to prevent powerful backwash from washing away beach materials beneathe the walls and so will cause undermining of the base of the walls and cause collapse and $$
2) Breakwaters
- To protect coast and harbour
- They are able to absorb energy waves before they reach the coast
- Can either be build with one end attached to land or be offshore
- If it is offshore, it will form a calm zone of water behind it.
- Deposition of load occurs behind it
Negative impact:
Only water behind the coast is protected, but those away will be unprotected and cause erosion at other parts of the coast.
3) Groynes
- Built at right angles to coast
- Prevent longshore drift
- Help to absorb and reduce wave energy only at side of groyne facing longshore drift but not
at downdrift and so erosion occurs there
- To prevent erosion, groynes is angled at 5-10 degrees frm coast
Negative Impact
Erosion will still occur at other parts of the coast
4) Gabions
-Wired cages filled with crushed rocks
- Help to reduce erosion by reducing energy waves
Negative Impact
Only short term protection of 5-10 years
A lot of regular maintainence needed (corrode by seawater, excessive trampling, vandalism)
Very costly
Soft engineering measure which does not involve building of any physical structure buut focusses on planning and managing coastal areas and properties to prevent it from getting damaged by erosion.
1) Beach Nourishment
- Involves the replenishing of sand so as to increase beach quality and storm protection.
Negative impact:
Very expensive
Destroy natural habitat: Sand that is washed into sea will cover the coral reefs and prevent them from getting sunlight to survive.
2) Relocation of Property
- Green Line policy to restrict building of houses near to coastal regions where flooding might
occur
Positive impact:
A very useful policy as global warming is causing an increases in sea level and so it will help to prevent chances of building being affected
3) Planting of Mangroves
- Mangroves have prop, long, curved roots that prop up to trap sediments
- New anchorage of roots will cause the plant to trap enough sediments to form island
- It will be extending outwards to the sea
Negative impacts
Some coast cannot take the stress of the mangroves as they are affected by destructive waves
The depth of the coast with plants will be shallower and so hinders maritime trade
4) Stabilising Dunes
- Happens in places with large amts of sand and strong wind
- Wind will blow sand further inland
- Sand will pile up to form coastal dunes (Protect coast from sea)
- They are fragile and shrubs struggle to hold them in place
5) Coral Reefs
- Coral reefs help to reduce wavee energy in water
- If they die, then the waters will move at full force and cause erosion to take place
- Can be made artificially by using environmental materials and put in sea bed
- Help to enhance fishing opportunities and act as undersea barrier to reduce chances of
erosion.
Saturday, September 27, 2008
Plants Wheeeeeeeeee.e...eeee.e..ee..e.e
Getting really really lame nowadays. LOL.
Hmmm... Getting bored now, so wanna post some info up again(:
Pressure Flow Concept is a really cool and interesting concept that I would really like to share with you all. It is somehow linked to Translocation which is the transport of substances like sugars manufactured to the other parts of the plants.
1) Sugars manufactured form the source will move out to the phloem (sieve tube)
2) Water will also move out to the phloem via osmosis
3) Water present will cause a pressure gradient for sugars to move through the sieve tubes.
4) In areas where sugars are used up or removed for storage, sugars will move out of phloem
via diffusion or active transport.
5) Water will then move out of phloem and get conducted back to xylem.
(Therefore, aphids will Ooozzzze out a fluid which is actually sugars)
Hmmm.... Transpiration is a process whereby water is loss through the stomata of the leaves
Transpiration pull is resulted from a few procedures:
1) Water from the mesophyll moves out via osmosis and forms a thin film of moisture
2) Thin film will then evaporate to the intercellular spaces and leave the plant via stomata
3) Cells that loses water will have decrease in water potential and so will get water from
deeper cells.
4) Deeper cells get water from xylem directly and so will form a suction force to pull water
upwards, causing transpiration pull
Water moves up xylem in 3 ways:
1) Root Pressure:
Difference in water potential between soil and roots will cause water to move from soil to roots and this pressure created will force water from root hair cell up to xylem vessel
2) Capillary Action:
Cohesion forces between water molecules and adhesive forces between water and xylem vessels will allow water to be conducted upwards without breakage.
3) Transpiration Pull:
Due to cells that draw water directly from xylem vessels, allowing water to move against gravity.
Transpiration rate affected by a few factors:
1) Wind Movement: Higher amount of wind present will lead to water vapour to be blown away and lesser humidity allows more water to move out of plant.
2) Humidity: The more humid, the lesser transpiration as high water potential in surrounding will hinder water out of the leaves.
3) Temperature: Higher temp. will allow water vapour to be evaporated off quickly and so allowing more water to move out due to less humidity
4) Light Intensity: More light will cause stomata to open as photosynthesis occurs and so more water vapour will move out of plant.
5) Water potential: More water supplied to plant, will allow plants to lose more water without wilting.
Wilting occurs when more water loss than uptake and will cause plant cells to become flaccid and photosynthesis cannot take place.
1) Leaves fold up to reduce surface area for sunlight
2) Guard cells become flaccid and closes stomata
Transpiration importance:
1) Allow biochemical reactions to take place.
2) Give plant cells turgor pressure to keep upright
3) A very good solvent
Transpiration's bad:
Causes wilting
Xylem- Conducts water and to provide plants with mechanical support with its lignified wall
Phloem- Conducts food substances and ions
How do plants reduce transpiration:
1) Having a thick boundary layer where water have to move through a long way before it can move out
2) Having a cuticle layer
3) Having hair: Reabsorb water back to plant and prevent excessive loss of water
Joelle (:
Hmmm... Getting bored now, so wanna post some info up again(:
Pressure Flow Concept is a really cool and interesting concept that I would really like to share with you all. It is somehow linked to Translocation which is the transport of substances like sugars manufactured to the other parts of the plants.
1) Sugars manufactured form the source will move out to the phloem (sieve tube)
2) Water will also move out to the phloem via osmosis
3) Water present will cause a pressure gradient for sugars to move through the sieve tubes.
4) In areas where sugars are used up or removed for storage, sugars will move out of phloem
via diffusion or active transport.
5) Water will then move out of phloem and get conducted back to xylem.
(Therefore, aphids will Ooozzzze out a fluid which is actually sugars)
Hmmm.... Transpiration is a process whereby water is loss through the stomata of the leaves
Transpiration pull is resulted from a few procedures:
1) Water from the mesophyll moves out via osmosis and forms a thin film of moisture
2) Thin film will then evaporate to the intercellular spaces and leave the plant via stomata
3) Cells that loses water will have decrease in water potential and so will get water from
deeper cells.
4) Deeper cells get water from xylem directly and so will form a suction force to pull water
upwards, causing transpiration pull
Water moves up xylem in 3 ways:
1) Root Pressure:
Difference in water potential between soil and roots will cause water to move from soil to roots and this pressure created will force water from root hair cell up to xylem vessel
2) Capillary Action:
Cohesion forces between water molecules and adhesive forces between water and xylem vessels will allow water to be conducted upwards without breakage.
3) Transpiration Pull:
Due to cells that draw water directly from xylem vessels, allowing water to move against gravity.
Transpiration rate affected by a few factors:
1) Wind Movement: Higher amount of wind present will lead to water vapour to be blown away and lesser humidity allows more water to move out of plant.
2) Humidity: The more humid, the lesser transpiration as high water potential in surrounding will hinder water out of the leaves.
3) Temperature: Higher temp. will allow water vapour to be evaporated off quickly and so allowing more water to move out due to less humidity
4) Light Intensity: More light will cause stomata to open as photosynthesis occurs and so more water vapour will move out of plant.
5) Water potential: More water supplied to plant, will allow plants to lose more water without wilting.
Wilting occurs when more water loss than uptake and will cause plant cells to become flaccid and photosynthesis cannot take place.
1) Leaves fold up to reduce surface area for sunlight
2) Guard cells become flaccid and closes stomata
Transpiration importance:
1) Allow biochemical reactions to take place.
2) Give plant cells turgor pressure to keep upright
3) A very good solvent
Transpiration's bad:
Causes wilting
Xylem- Conducts water and to provide plants with mechanical support with its lignified wall
Phloem- Conducts food substances and ions
How do plants reduce transpiration:
1) Having a thick boundary layer where water have to move through a long way before it can move out
2) Having a cuticle layer
3) Having hair: Reabsorb water back to plant and prevent excessive loss of water
Joelle (:
2 goodbye(:
YESYESYES! ENGLISH AND SS IS LIKE FINALLY OVER! (:
Waiting for the arrival of the rest(:
Joelle
Waiting for the arrival of the rest(:
Joelle
Tuesday, September 16, 2008
How bonded we are!
Challenges faced in maintaining peace in Singapore in the early years...
1) Managing Perceptions of different Racial Groups.
- Resulted in the race riots between different racial groups
- All beacuse of UMNO who spread that PAP was unfair to the Malays by highlighting the Malays' poverty.
- These stirred up unhappiness amongst the Malay community towards PAP
- The policies have affected people from different groups, irresponsible media reporting and purposeful propagating had made the Malays doubt their status in Singapore.
- Shows that if racial problems are not settled properly, will result in suspision and unhappiness amongst the different groups.
2) Managing Perceptions of different Religious Groups
- Maria Hertogh Riots over the custody of the girl, Maria
- Put under the care of a Malay lady when her parents were captured during the Japanese Occupation
- She was brought up as a Malay lady and even married a Malay teacher
- After war, Maria's parents came to get her back, and a court trial followed.
- Custody given back to the Hertoghs and caused the whole group outside to feel unhappy as they felt the British legal system was unfair towards them
- This aroused unhappiness amongst them towards the European and Eurasian communities.
- Case had many wide media coverage which made Malays feel upset as they felt their welfare were not taken care of.
- Caused the riots which led to 5 dead and 100 injured.
- Shows that if racial problems are not handled appropriately, will lead to hostility and distrust amongst the people.
3) Threats from External Forces
-Transnational Act refers to acts of violence that are global in terms of aims, organisation and impact. Example of this is Jemaah Islamiyah, a militant group that aims to set up an Islam state in Asia region
- S'pore was part of their aim after bombing areas like Jarkarta and Bali
- Aimed to bomed US embassy and gov ernment buildings
- 34 members captured for being involved in terrorism acts btw 2001-2004
- 1 memer caught in 2005
- These acts of violence, if successful, will kill and harm many people. Even if halted, it will test the social bonds of the people and may even divide the people.
- People who do not see things in perspective will blame the Muslims in S'pore for the act of violence done by Muslims of other countries and thus start to avoid them and make them feel unwelcome.
-Racist remarks hurled at them even though they had not done anything wrong.
- Muslims will thus feel unhappy.
-People who are influenced by JI radical ideas may be tempted to join and this will result in separation of the people.
1) Managing Perceptions of different Racial Groups.
- Resulted in the race riots between different racial groups
- All beacuse of UMNO who spread that PAP was unfair to the Malays by highlighting the Malays' poverty.
- These stirred up unhappiness amongst the Malay community towards PAP
- The policies have affected people from different groups, irresponsible media reporting and purposeful propagating had made the Malays doubt their status in Singapore.
- Shows that if racial problems are not settled properly, will result in suspision and unhappiness amongst the different groups.
2) Managing Perceptions of different Religious Groups
- Maria Hertogh Riots over the custody of the girl, Maria
- Put under the care of a Malay lady when her parents were captured during the Japanese Occupation
- She was brought up as a Malay lady and even married a Malay teacher
- After war, Maria's parents came to get her back, and a court trial followed.
- Custody given back to the Hertoghs and caused the whole group outside to feel unhappy as they felt the British legal system was unfair towards them
- This aroused unhappiness amongst them towards the European and Eurasian communities.
- Case had many wide media coverage which made Malays feel upset as they felt their welfare were not taken care of.
- Caused the riots which led to 5 dead and 100 injured.
- Shows that if racial problems are not handled appropriately, will lead to hostility and distrust amongst the people.
3) Threats from External Forces
-Transnational Act refers to acts of violence that are global in terms of aims, organisation and impact. Example of this is Jemaah Islamiyah, a militant group that aims to set up an Islam state in Asia region
- S'pore was part of their aim after bombing areas like Jarkarta and Bali
- Aimed to bomed US embassy and gov ernment buildings
- 34 members captured for being involved in terrorism acts btw 2001-2004
- 1 memer caught in 2005
- These acts of violence, if successful, will kill and harm many people. Even if halted, it will test the social bonds of the people and may even divide the people.
- People who do not see things in perspective will blame the Muslims in S'pore for the act of violence done by Muslims of other countries and thus start to avoid them and make them feel unwelcome.
-Racist remarks hurled at them even though they had not done anything wrong.
- Muslims will thus feel unhappy.
-People who are influenced by JI radical ideas may be tempted to join and this will result in separation of the people.
How much you know about DIALYSIS!
hmmm.... Most of you should know that dialysis is all beacuse of kidney failure. But why?
Kidney failure may be due to overworking of kidney cells and causing them to die. They will not be able to:
1) Remove excretory waste like urea, ammonia and uric acid (Poison blood is not removed)
2) Maintain pH and composition of blood
3) Act as an osmoregulator
Haemodialysis
At the end of the treatment, urea and excess mineral salts will be found in the solution
- Urea is able to diffuse into peritonium and thus will allow this treatment.
Kidney failure may be due to overworking of kidney cells and causing them to die. They will not be able to:
1) Remove excretory waste like urea, ammonia and uric acid (Poison blood is not removed)
2) Maintain pH and composition of blood
3) Act as an osmoregulator
Haemodialysis
Properties of dialysis machine
1) Highly folded convoluted tubes: Increase surface area for diffusion of substances
2) Small holes present in tubes: Allow only small particles such as urea and glucose to pass though and not large protein molecules or red blood cell
3) Flow of dialysate is opposite to flow of blood: Maintain a concentration gradient to allow efficient diffusion of urea out of blood
4) Glucose and Salt in correct composition: To allow only substances above that concentration to diffuse out.
Peritoneal Dialysis
At the end of the treatment, urea and excess mineral salts will be found in the solution
- Urea is able to diffuse into peritonium and thus will allow this treatment.
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