no scolding from piano teacher today! surprise, surprise!

Updated profile, on your left.

SS test was okay. Just ok.

"Girls, last two minutes, finish up your last sentence."
wth, i still have 1 paragraph la!
*scribbles frantically*
"ok, stop writing."
shit shit shit.
"I said STOP WRITING."

Lol I managed to finish up my lousy paragraph 5 of the SEQ. So that was the test, one period of accounts eaten up =D Haha. Mrs Eng likes 3c2 more than 3c1. I did extremely well for the cashbook test. Overall this term is A1 :)

POA lesson:
"Madeline, why are you talking to yourself?
Scary."
-Mrs Eng

Miss Tey didn't come in for class. 2 periods of slacking. I was sleeping la. Those around me were talking about GB stuff. Miss Kok's maths classes are the pitiful ones. lol.. promoted to outside seat if you fail her maths quizzes. They have been sitting there since dunno when lor.

PW, English, Geog. 3 projects. One is due next Tuesday.

Geog test tmr, sure die. Give up hope already... only studied natural vegetation. Weathering is like, gone case. Chem and music test on Thursday, bio on Friday, E maths next Tuesday. Damn stressed can..

There's hope for chem and maths :D
thanks

Weathering is the disintegration and decomposition of rocks in situ, meaning they remain where they disintegrate or decompose and are not carried away from their original site; in other words, NO TRANSPORT IS REQUIRED IN WEATHERING.

Eroision is the wearing away of rocks by moving agents (winds, waves, rivers, glaciers) which then carry the rock material away from the original site. Unlike weathering, transport is involved in erosion.

Physical Weathering
-Disintegration/breaking down of rocks into smaller pieces
-size and shape of the rocks (physical appearance?) of the rocks are altered but not their chemical composition.
-Products of physical weathering usually coarse and angular.
-more effective in areas with:
-little vegetation
-large diurnal range of temperature or
-temperatures fluctuating around 0°C

Chemical Weathering
-Decomposition of rocks when minerals in the rocks react chemically with rainwater, seawater, carbon dioxide and oxygen to form one or more new chemical coumpounds.
-Chemical changes weaken the rocks which break down over time.
-Alters the ohysical structure and chemical composition of the rocks.
-One or more new chemical compounds that are formed are fine-textured.
-Most effective in hot, wet areas.

Types of Physical Weathering
Frost shattering/freeze-thaw action
Conditions conducive to frost shattering are
-an aduquate wupply of moisture
-the presence of joints, fractures, bedding planes or pore spaces in rocks
-temperatures flactuating around 0°C

When water that has entered the joints freezes, the ice formed strains the walls of the joints and causes the joints to deepen and widen. This is because the volume of water expands by 9% when it freezes.

When the ice thaws, water can flow further into the rock. When the temperature drops below freezing pointand the water freezes again, the ice enlarges the joints further.

Repeated freeze-thaw action weakens the rocks which, over time, break up along the joints into angular pieces. The angular rock fragments gather at the fort of the slope to form a talus slope (or scree clope). The splitting of rocks along the joints into blocks is called block disintegration. The blocks of rocks that are detached of various shapes depending on their rock structure.

Ice crystals can also form in the pore spaces of rocks. They grow larger as they attract water that has not frozen from the surrounding pores. The ice crystal weakens the rocks which, in time, break up. An exapmple of rocks suscetible to frost action is chalk, which has many pore spaces for the growth of ice crystals.

Laboratory tests show that frequent daily freeze-that cycles are more conducive than seasonal freeze-thaw cycles to frost shattering.

Insolation weathering/thermal expansion
Supporters of insolation weathering believe it is a major physicalprocess in deserts. Deserts have a large diurnal range of temperature. Day temperatures can rise up to 35°C or higher because of the lack of cloud cover to reduce incoming solar radiation/insolation. Night temperatures can go down to 10°C or lower because of the lack of cloud cover to prevent outgoing terrestrial heat from escaping back into space.

Rocks expand when heated in the day and contract when they cool down at night. However, the rocks are not heated up right through. It is the outer parts that heat up and expand, and cool down and contract. The repeated expansion and contraction of the outer parts form cracks. Evantually, the outer parts of the rocks peel off in layers. This type of weathering is called onion peeling or exfoliation.

Different coloured mineral grains in a rock expand at different rates when heated. The darker minerals absorb more heat and expand more than the lighter minerals. The differential expansion causes stresses between adjacent grains and the rock will disintegrate grain by grain. This is called granular disintegration.

Salt crystal growth
Salt crystal growth in rocks can be found especially in arid regions where the ground water containingdissolved salts such as sodium sulphate is drawn up to the surface by capillary action.

When water evaporates, the salts are left behind as crystals in the pore spaces, cavities and joints the rocks.


sick of typing. shall go back to writing. lol.