Pour me a heavy dose of ATMOSPHERE.

Hello class! I think you all need a recap of what we learnt last term (i.e. IS2104 Tutorial 2, 15 January 2010, haha). So let's rewind to 3 months ago, when we did not have the TC block classroom, when we were not boarding, when the weather was not so hot.

Your mind should now think that it is now 15 January 2010.

Today, we went through the answers for the 'Layers of the Atmosphere' worksheet that we were given. During the previous lesson, we were told to plot the graph to identify the different layers of the Earth's atmosphere with respect to the altitude and the temperature. We then found out that the basis for dividing the atmosphere is due to the different temperature changes. From the graph, we can tell how each layer's temperature varies with how far the layer is away from the Earth. We have learnt that:

• Troposphere, 17 km, -60°C, decreases with altitude: As the density of the gases in this layer decreases with height, the air thins. The heat that hits the Earth's surface gets reflected upward and converted into heat. Therefore, the higher you go in the troposphere, the colder it is, until you hit the ozone layer in the stratosphere.
• Stratosphere, 50 km, -2°C, increases with altitude: The increase is caused by the ozone layer capturing and absorbing ultraviolet radiation by the sun.
  
• Mesosphere, 80 km, -90°C, decreases with altitude: The amount of air decreases, and there is no ozone, and thus the temperature decreases. In fact, the mesosphere is the coldest layer of the atmosphere, dropping to a temperature of -90C.
• Thermosphere, 690 km, 2,000°C, increases with altitude: There are very few molecules present in the thermosphere, and thus they receive large amounts of heat energy from the sun, causing the layer to warm to such a high temperature. Air temperature, however, is a measure of the kinetic energy of air molecules, not of the total energy stored by the air. Therefore, since the air is so thin within the thermosphere, such temperature values are not comparable to those of the troposphere or stratosphere. Although the measured temperature is very high, the thermosphere would feel cold to us because of the small energy of only a few air molecules residing there to transfer any heat to our skin.

So the shape of the graph on page 3 of the worksheet should look something like this:


Yup that was all that we learnt for this lesson, hope this entry helped you understand more about our atmosphere!

Okay you can now think that it is 24 April 2010.

Adelia Ng (01)

What I have learned from my individual essay.

Hybrid rice

This Tuesday I got my essay paper back and I read the feedback that Miss Kavi wrote for me. I think I learned a lot from this. My essay is about how effective hybrid rice achieves sustainability.

The first paragraph I gave a brief introduction about how important it is for us to achieve food security and maintain sustaniable enviornment. In the following paragraph I explained what is hybrid rice. Then I justified how it is effective for sustainable enviornment by using system approach.

As Miss Kavi mentioned it would be better for me to justified using system approach as a whole rather than I state the input is "seed" and the output is "rice". Further I think adding a diagram will make my essay much more clear for readers to understand. Another thing that Miss Kavi pointed out is that I should avoid use rhetorical qustion in my essay. I will not do this again.

I learned a lot from the essay. I learned how to get useful information. Because hybrid rice is invented in China therefore more information could be found in Chinese and I have to translate that into English. It's quite challenging but also quite fun. I also learned the basic skills of writing a essay. Expressing much but in few words is important so we should make our language clear and succinct.

16 Yuzhi

6th April

Hi class(:
Don't forget:
TERM FOUR, WEEK TWO
We've got our 2nd MCQ Geog test!

Anyway, our last lesson, we learnt about water balance and how to calculate it.

The basic equation would be

P = E + Q ± ∆S

This equation basically accounts for the Inputs, Outputs and Storage changes within a watershed.

A majority of the input is due to precipitation, more commonly known as rain.

A majority of the output is due to evapotranspiration, and storage is the water that is held in the soil.

From this, we can read the equation more easily, if we take P to stand for total precipitation, E for Evapotranspiration, Q for total runoff and S for soil water storage.

Soil water is constantly changing, therefore the triangle stands for the change in S.

Then we moved on to the worksheet, about how human activities affect the hydrological cycle.

Damming, which is usually done to harness hydroelectric power, to prevent flooding, for irrigation purposes or as a tourist attraction, increases surface storage, and thus evaporation as well as reduces runoff.

Cloud seeding causes an increase in impurities in the water vapour in the air, which results in an increase in condensation and therefore an increase in precipitation. This increase causes all other flows to directly increase.

Agriculture causes a decrease in interception/increased infiltration because the crop rows leave a lot more bare soil than when compared to a forest. Ploughing also helps to increase infiltration because the soil gets loosened and thus more water can seep into the earth.

Grazing by animals reduces infiltration beause animals stand and pound and compact the soil, causing the top layer to have fewer air spaces which can be filled by water. So the top soil layer quickly reaches field capacity.

Urbanization causes a reduction in infiltration and an increase in surface runoff due to the cement pavements. The concrete also traps more heat, resulting in a slight increase in evaporation. Increased surface storage also causes an increase in evaporation. The lack of vegetation causes a reduction in evapotranspiration.


Okay yeap, that's pretty much it for 6th April!

Happy Studying!(:

-Nisha (11)☺

Hydrological cycle!

Other important things to note

Distributary: A branch of a river that flows away from the main stream

Tributary: A stream that flows into a larger stream or other body of water

River mouth: an opening in a river that flows into another body (usually sea)

River source: where the river originates (opposite end of the river mouth, usually from the highlands)

For example, could you label where the distributary, tributary, river source and river mouth is in the diagram?

Marie Pang (12)