♥ Friday, May 29, 2009 ♥

Heyhey!
Sorry for the lag post and all :/
Anywayyy! Time to summarise the entire module! Basically, we covered 2 major spheres in this module: atmosphere &hydrosphere (:

For atmosphere:

Basically, we learnt about the composition of air -78% nitrogen, 21% oxygen and 1% other gases and learnt how oxygen is important to sustain life because it is reactive and forms compounds with various elements, allow humans to use it for respiration and life processes. Such a composition is ideal to sustain life.

Later, we learnt delved deeper into the presence of carbon dioxide in the atmosphere (0.03%) though the carbon cycle. Basically, we learnt that carbon dioxide is taken in by plants, then, as the plants & animals decompose, they give off carbon. Also, as they respire, carbon dioxide is given out. If dead plants & animals do not fully decompose they will form fossil fuels, storing carbon in the earth. Carbon dioxide is dissolved in the ocean as well, providing aquatic plants with energy. From this, we realize that plants & animals give off carbon when they respire and decompose, while plants take in carbon dioxide via photosynthesis and carbon dioxide is absorbed by the ocean as well to allow aquatic plants to respire.

We also learnt how man’s actions have interfered with the carbon cycle, thus, resulting in an increase in global warming as well. E.g. deforestation: results in less trees and thus, less carbon dioxide is removed from the atmosphere, increasing carbon dioxide levels and thus, increasing the amount of greenhouse gases, thus, resulting in global warming.

Then, we went on to learn about rain: frontal, relief and convectional rain. Essentially, frontal rain occurs when either warm air meets a cold front, or when cold air meets a warm front, resulting in the warm air rising and thus, adiabatic cooling occurs and it rains. Relief rain occurs when air is forced to rise when it meets a relief (e.g. mountain) causing adiabatic cooling, and rain to form on the windward side (facing sea) thus causing the leeward side (facing away from sea) to be dry. This may allow for the formation of deserts. Lastly, convectional rain is simply warm air rising and thus resulting in adiabatic cooling, and thus, rain. (:

Then, we learnt how to interpret climographs. Basically, its just describing how warm&wet a place is based on the data provided.

From the lesson on climographs, we realized that different countries have different climates, why is this the case? This is where the global air circulation model comes into play. Essentially, the global air circulation model looks like this!

which then results in the various different climates in the world, as well as the formation of deserts between the hadley cell and the ferrel cell. This is because air at the ferrel cell moves upwards while air at the hadley cell moves downwards, resulting in no adiabatic cooling occuring, and thus, no rain formation, making that area dry, and thus, forming a desert. * deserts are also formed due to relief rain (:

essentially, that concludes the atmosphere component!

:D:D:D

....now moving onto the HYDROSPHERE, which will be continued in the next post.

Crapped at 6:43 AM - 2 comments

♥ Sunday, May 3, 2009 ♥

Ok, right, time goes by and it was my second time to write the post.
In the 30 minutes lesson, we have learnt about the WATERFALL and MEANDER.
So let’s begin with the waterfall. The waterfall is a steep descent of water from a height. It usually found in the upper course of a river in the hills or mountains.
A WATERFALL=A STEEP DROP OF WATER
Formation of Waterfalls:
--It forms when a band of hard resistant rock lies over softer, less resistant rock.
--The softer rock is quickly eroded by hydraulic action and abrasion, causing the harder rock to be undercut.
--The hard rock overhangs until it can no longer carry its own weight.
--The overhang collapses and then breaks up in the water below.
--The great power of the water at the base of the waterfall causes a plunge pool to form.
--The bed of the river below the waterfall contains boulders eroded by splash back from behind the waterfall.

Some Facts of Waterfalls:
The tallest waterfall in the world is the Angel Falls. It is 979 metres high.
The highest waterfall in Africa is the Tugela Falls at 947 metres. It is found in South Africa.
Europe's highest waterfall, Utigard in Norway, is 800 metres high.
The Yosemite waterfall (739 metres) is the highest waterfall in the USA.

Secondly, we learnt meanders which are curves or bends along a river. It is usually found in the middle or lower course of a river.
MEANDER=A BEND IN A RIVER
Formation of Meanders:
A meander is formed when the moving water in a river erodes the outer banks and widens its valley. A stream of any volume may assume a meandering course, alternatively eroding sediments from the outside of a bend and depositing them on the inside. The result is a snaking pattern as the stream meanders back and forth across its down-valley axis.

Cause of Meanders:
Helicoidal Flow=Spiral Movement of Water
It will move eroded river load from the outer bank and then deposited much of it on the next inner bank of a river.
Top current: hits against the river bank and undercuts the eroded material.
Bottom current: carries the eroded material and deposits them in the next inner bank.

Yeah, I guess it’s all. Hope you can understand.
Enjoy the half day, heh heh.
Done by Violet

Crapped at 6:10 AM - 2 comments

♥ Monday, April 27, 2009 ♥

Hello I'm being responsible and blogging today! (like right after today's lesson)
Haha hooray me, and for us! :D

So firstly, we learnt about THE RIVER PROCESSES today. :)
Basically, deposition-> transportation -> erosion.
Which means that, after deposition, if there is still excess energy, transportation will take place, and again, if there is still some more excess energy, erosion will take place.
Now, let me show you a graph, which would help to enhance your understanding! ;)

Critical erosion velocity (the Hjulstrom curve)

Okay, I hope that you've understand the first part of today's lesson.
Next, we went deeper into the transportation process!

Traction- Heaviest/Largest material is rolled along the river bed, and this requires the most energy out of all the subgroups.
Saltation- Sand-sized particles bounce along the riverbed in a "leap-frog" motion.
Suspension- Smaller particles (silt and clay-sized) are carried within the water by turbulent flow. Turbulent flow refers to water not flowing straight. :)
Solution- Some minerals will be dissolved in the water and will be carried in the solution, and this requires the least energy.

Now moving on, if there is still excess energy, erosion will take place.

There are 4 types of erosion:
1) Corrasion
2) Hydraulic Action
3) Solution
4) Attrition

Corrasion, or also known as Abrasion, targets the bedrock. The nature of corrasion is either called the 'drilling' or 'sand paper', which is the rubbing effect on sediments. The outcome of this process are potholes banks, which are wider and also smoother because of the 'sand paper effect'.

Hydraulic Action, or also known as Weathering, targets cracks. The nature of this process is air pressure. Air pressure increases when water seeps into the cracks, and air pressure decreases in the cracks when the water flows out. This will cause the cracks to expand, and it is an explosive process. The outcome of this process are collapsed banks.

Solution, targets the bedrock too. Bedrocks are rocks which have not been weathered yet. And the nature of this process is chemically driven.

Attrition, targets the sediment load. And this process takes place because of the impact of the sediment load constantly knocking against each other. The outcome of this process is the formation of smaller and rounder rocks.

Its the end! Haha yay aren't you glad, thats all! (for the erosion process) ;D

Now imagine a hill...
Okay nevermind, I shall attempt to draw it out for you on paint! :/

There you go! HAHA :)

Now to explain about the River Valley...

Upper Course takes the shape of a V-shaped valley due to mass movements, such as landslides and avalaunches. This is called vertical erosion, which deepens the bedrock channel, thus forming landforms like the Grand Canyon.

This beautiful picture shows the famous Grand Canyon of Yellowstone. The V-shaped valley is very obvious in here. :)

Middle Course takes the shape of a wider and flatter valley as a result of the sediments being already weathered, and broken down. This can also be named as alluvial. There is increased sinuosity, which means the distances widens and increases, which forms landforms like meanders and grasslands.

This picture shows a typical meander along the grassland. Notice that the grassland is much flatter and wider than the valley along the upper course. :)

Lower Course also takes the shape of a wider and flatter valley. The reason to this formation is exactly the same as how the middle course forms a wide and flat valley. At the lower course, floodplains and levees are the types of landforms formed.

The picture shows a floodplain, which is flat or nearly flat, and is adjacent to a stream or river. This position causes it to be flooded occasionally. :)

Hope you enjoyed reading this post!

Haha alright, see you people around.

By, Joel Tay (22)

Crapped at 7:39 AM - 3 comments

♥ Sunday, April 19, 2009 ♥

Sorry o3, totally forgot about this!

I'll be referring to the handout.

Page 230: Diagrams

If the shape of the drainage basin is as in the diagrams, then the gauging station is located at the bottom edge of the basin, in order to gauge the entire basin (if it was located at the middle, it would only gauge part of the drainage basin).

Hydrograph of Diagram 1:
-Short lag time
The highest discharge is at the bottom of the basin, due to the wider area and the large amount of tributaries.
Thus, the highest amount of discharge is within the "early" time zone (that is, it reaches the gauging station earlier), leading to an early peak.

Hydrograph of Diagram 2:
-Long lag time
The highest discharge is at the top of the basin, as there is a larger area at the top, so it collects more rainwater.
Thus, the highest amount of discharge is within the "late" time zone (that is, it reaches the gauguing station later), leading to a late peak.

Hydrograph of Diagram 3:
-Double lag time
There are two areas with the highest discharge, one at the top and one at the bottom of the basin, due to the wider areas here.
This leads to a double-peak as the two main discharges reach the gauging station at two different times.

Soil and water:
Base flow comes below the soil
Throughflow comes through the soil
Overflow comes above the soil

Ground water is below the soil and acts like a store of water (it is just above a rock layer), which is a long-term store (as opposed to surface water bodies) and can last for millennia. It is the source of water for wells. It is due to the fact that some rocks are quite porous and can "hold" water after it comes down through percolation, which comes after infiltration.

Throughflow is a less consistent store of water, as opposed to ground water, and it is faster than baseflow. It occurs through infiltration of water through the soil.

Baseflow is slower than throughflow, but it is more consistent than it, since it draws from ground water stores.

The drainage density of a basin is related to the efficiency of the flowing of water (or something like that). The higher the density, the more efficient the flow of water is, leading to a shorter lag time, and vice versa.

A bit on Pg 230, regarding the shape of the basin:
Long basin
-Consistent amount of water
-Early and late time zones both produce the same amount of water.
-Thus, there is an extended peak, as the water does not come all at once.

Round basin
-The discharge reaches the gauging station at around the same time.
-This leads to a short but sharp peak.

Calvin

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♥ Wednesday, April 8, 2009 ♥

Firstly I would like the emphasize that in this post, I would not post pictures/excerpts from our geog textbook as I think it is redundant to do so since it isn't that hard to refer to your geog textbook.

To start things off:

Mr Faizal was once again explaining to us about the water balance because we were unsure about it. This time, he drew a diagram so I took it down...note that not all aspects of the water balance are illustrated here.

Storm Hydrograph:

(enlarge the photo to have a closer view)

This one caused quite abit of a stir...

Lag time: When a rain drop falls, the water level of a river does not shoot up immediately due to drainage. A rain drop still has to go through various processes occur before the water reaches the river. An example would be...imagine that you are a raindrop( so fun! ) and you precipitated down to earth. You land on the soil and infiltrate it. Thereafter, you would percolate and via throughflow, you reach the river. Hence, from this you can see, time was needed for the water to reach the river. This is lag time. Something to take note, a drainage basin with a steeper profile has less lag time and a drainage basin with a gentler profile has a longer lag time due to the speed at which the water reaches the river.
Rising Limb: After some time, water from the drainage basin would arrive at the river and it's water level thus rises.
Max. Capacity: When the river reaches it's maximum capacity and water is still flowing towards it, the river overflows its banks.
Recession Limb: When it stops raining(precipitating) some water within the drainage basin which hasn't reached the river continues its journey to the river. After which, the water level of the river slowly recedes and this is reason for the recession limb.
Rainfall Chart: The graph of the rainfall.

Yayy hope you understood it xD

Done by.. me. (:

Chunwai.

Crapped at 5:29 AM - 0 comments

♥ Tuesday, March 31, 2009 ♥

hellow friends. mr heah was misfortuned to have been involved with an accident. it was shocking news for one and all. so, on behalf of the class, WE HOPE YOU GET WELL SOON and HAVE A SPEEDY RECOVERY mr raynard heah!!

carrying on, we had a relief teacher in place of mr heah, mr faizal. we were honoured to have a distinguished man on board njc's teaching staff. nice man he was, but unfortunately for him, he was not aware of which topic to start on and so went all the way back to the start. that was on adibetic cooling.

what i felt of the lesson was that it was a good revision for us (:

give me geography and i'll mug for it!!
thats my lifelong motto!

okay, guys. so i got a second chance at proving my worth in yet another blog post.
last lesson we covered the topic of water balance!

first of all. water balance is just another way of balancing things in life. dare i ask you to recall last term's MI topic of chinese medicine. one part to it was yin and yang. the concept behind water balance is the same.

it is an explanation of how water is never 'destroyed'. only 'transferred' elsewhere.

that is why P which is Precipitation/Rainfall will equal to all water 'transferred' through various processes.
those are, Q which is water flowing down above the ground (Runoff)
E which is Evapotranspiration, the water taken in by roots and transpired out back into the air

deltaS which is change in Storage of water in bedrocks or soil.

further details about deltaS, most importantly, you have to understand S is Storage of water in bedrock or soil. if the amount increases the next month, the change in Storage is positive.

and so, the equation of P = Q + E + deltaS is to explain where the water from precipitation goes. be it back into lakes through runnoff, and transpired back into the air by evapotranspiration, and stored in bedrocks or soil. the water in bedrocks, if increased means part of the precipitation is being stored there.

HENCE

this is to simplify all that i have mentioned in the post (:

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♥ Wednesday, March 25, 2009 ♥

we went to the "hidden area" of nj today, near the container classrooms. and Mr Heah reminded us once again on how all systems are connected. the hydrosphere affects the atmosphere at some point, and vice versa. they are not in a vacuum, and neither can they be. if there was little or no rain, then soon plants will die, then the atmosphere will be affected due to the lack of plants, then the animals will die.. and the animals that prey on those herbivores die.. and so on. not to mention no rain means no cloud cover, and the temperature of the earth's surface will go up by alot.

we then went on to the lesson

we first explored the flow of water

lets imagine we are a raindrop. after finally falling, where will we go? assuming we fell over a forest, some of us may seep into the ground, some get intercepted by trees, some just hit the ground and flow off.

basically interception is just the tree, or grass, basically vegetation trapping the water, and preventing it from reaching the ground (though some will eventually)

but sometimes, when a raindrop hit s the leaf, it drips from one the the other! this is called throughfall. "through" the leaves, "falling" down.

if i flow down the stem/trunk then its called stemflow! flowing down the stem, essentially.

if i collect in depressions in the ground, as we see many times in urban areas, its called depression storage. if i evaporate/transpirate back, then its called evapotranspiration.

of course, i'll hit the ground also, and i'll seep into the soil! this is called infiltration. the ground though, also has an infiltration capacity, and infiltration rate. and sometimes if the ground doesn't soak me up fast enough,(too low infiltration rate) then some of me will flow off the surface. (which is also called overland flow. the term is self explanatory)

what is so amazing, is that concrete has a really really low infiltration rate/capacity, and it was really really dry (at the "hidden" area of nj), but at the grassy soil part, man it was wet! and life was teeming there. just shows how important water is to life. another example would be a desert, the ground is all sand, no soil, super little water, thats why there's little life!

sometimes when i (the raindrop) hit the ground, but its a hill/slope, then i'll move with gravity, downwards, but also along the "x" axis plane. this is described as throughflow.

then we went on to the drainage basin. the drainage basin is basically where the water is drained from, to a certain point. so as Mr Heah demonstrated, when we picked different points of a river, or in this case a drain, the drainage basin would be different. yup.

just a few thoughts. (not sure if all are right though)

why are drainage basins important? because if not for drains, we would experience floods! the water would just stay where it was, and we would have to manually transport every drop away. good thing that things were made in such a way that naturally, somehow, the drainage basins work, and we not get a flood every time it rains. of course urbanization has changed alot of things, (lots of concrete around..) and we now need lots of manmade drains, to prevent flooding.

allow me to talk a little about the little excursion we had with Mr Heah after the lesson, where he took us to places to find plants through the concrete ground. somehow, as long as there's a little bit of water, life has an opportunity to grow, and when the little hardy plants die, there is a some organic material there, for other plants to grow, and soon, (forgot what the term was) more and more life can be found! if you go to the level where our class is, coming up by the staircase near the bookshop, and turn left, look around, you will find a pretty plant, with stem and all. amazing.

jonathan

Crapped at 7:25 PM - 1 comments

08IP03! (:

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