TILT AND SHAPE!!!

In my opinion, today's lesson was quite interesting and it was something like self-study with the assitance of our geog teachers. We tried to explain two important things which were the distribution of the Earth's climate and the reasons why there are seasons on Earth.

Chengxi, Kah Eng and I were in the same group and our task was to discuss and explain the distribution of Earth climate.

From the World map of Koppen-Geiger Climate Classification, there are some things we noticed, some we could explain and some we couldn't or couldn't explain totally:

The nearer to the equator, the hotter it is: Our Earth orbits the Sun in an ellipse motion, it also spins on its own arround an imaginary axis which is tilted 23.5o. As a result, the equator is the part receives the most solar radiation, faraway from the equator, the less solar radiation there is, especially the North and South Poles, where the temperature is usually negative through out the whole year.

The different areas at the same lattitude usually have the same or similar kind of climate due to similar amount of solar radiation received. Moreover, there is symmetry between the Northern Hemisphere's climate and the Southern Hemisphere's climate. For example, (10 N, 20 E) and (10 S, 20 E) are the two places having Aw- Equatorial winter dry due to similar amount of solar radiation they receive as well.

Although equator receives the most amount of solar radiation, that area is not the hottest part on Eart. Deserts in Africa, Australia, Southern Asia and some parts of America are actually the hottest places on Earth, there might be different explanations regarding this phenomenon and we hope to know it the next lesson.

Chengxi also noticed that why the climare of the area connects the North and South of America continent is Am (equatorial monsoonal) and As (equatorial summerdry) even though it is at the same lattitude as the lower part of Sahara desert in Africa. I think one of the reason maybe it is a very thin stripe of land so that it has more contact with the sea, has more water vapor and become less dry....

The circulation of the wind between the two poles and the equator is partly due to the air pressure and the temperature. Air in the North and South Poles is colder, it has higher pressure and it sinks while air in the equator is hotter with lower pressure. Convection causes the cold air in the North and South poles to sink and flow to the equator while hot air near above the equator will rise and flow to the two poles.

Sea currents may affect our Earth's climate distribution as well.

That's all I have noticed about today's lesson, in the next lessons, I hope we can have a better understanding of the climate patterns.

Please comment this entry so I can improve on it :D
Linh :)

20-02-2009

In today’s lesson, we did some practices about describing climographs and then later on we did reflection about what we have learnt in this module :)

#First, I’ll touch on the climograph describing:
As mentioned in our previous lesson, there are some major points we should mention about climographs:
- Temperature: range + peak.
- Precipitation (rain, hail...): pattern, range (note: precipitation must come in mm)
- (Optional) sometimes elevation can also be used to describe climate.
Today we did some practices on climographs, and along the way, I picked out some points that should be noted:
- Some key words that should be used: seasonal, range (narrow/ wide), dry/ wet season, cold/hot, constant/variable, etc...
- Must pick out the general trend (eg: wetter months...)
- We can use the World map of Koppen- Geiger climate classification (the colourful map we were given) to locate the area where we’re describing and then we will know what’s the climate there.
- Climate of one area can be seasonal / not seasonal :D
- General statements should go first.
- There is no such thing as precipitate rate, just precipitate alone can do already.
- Take the graph as a circular system (cos every year we always have 12 months right? So instead of listing all the months like “December, January and February”, we can just say “from December to February”)
Most importantly, there’s no need to learn by heart any climograph description because we’ve known every necessary things to describe climographs. YOU KNOW IT, SO JUST DO IT!

#Now is our reflection!!!!!!!!!!!!!!!!!!!!! Basically we just mentioned what we have learnt in this module and connect all those things into a system so that we can see the relationship of all the stuff we’ve learnt :)

Yah, so that’s all we did today.

Cheers everyone!!!!!!!!!
Thu :)

HELLO OHFIVE! :D

Today we learnt something new called FRONTAL RAIN. As Ms Lin explained earlier, frontal rain happens when there is a region of warm air and another region of cold air. There are two types of frontal rain.

1. When cold air sinks, it forces the warm air to rise and condense. A cold front is therefore formed and heavy downpours occur.

2. When warm air rises due to a region of cold air hindering it's path, a warm front is formed.

We also touched a little on climate change today, and we learnt that the difference between weather and climate is the time frame of the two. Climate is defined by a period of about 30 years or more while weather is on a short term basis.

We learnt that precipitation and temperature are two very important things to take note when describing the weather. Also, we were taught how to describe CLIMOGRAPHS. There are two main points to take note of when describing climographs:

1. Temperature (i.e. range, peak, average)

2. Rainfall (i.e. patterns, range[how wet])

Please take note as well that it is safer to describe Singapore as having HIGH RAINFALL.

For a sample of how to describe Climographs, you may refer to the description of Singapore's Climograph in the notes handed out today. (:

'KAHENG(:

HELLO :D

Today, for the being of the lesson, we revise on the PLANETARY HEAT BALANCE for a period of time.
& here’s the summary for the whole idea of the heat balance:


we proceed on with the CLOUD-MAKING experiment.
We gathered around Ms Lin outside class in groups and she started the demonstration on how to make clouds appear in a 1.5 litre bottle.

For the experiment, a 1.5 litre bottle with some water in it and a matchstick is needed. Before starting, Ms lin squeeze the capped bottle and asked us "What is happening in the bottle?" Yes, air was being compressed and uncompressed inside the bottle before and after squeezing. (that's our answer)

Next, the matchstick was lit and entingushed inside the bottle. The smoke from the matchstick was then trapped in the capped bottle. The inside of the bottle looks misty at first but soon cleared away later.

After that,
Ms Lin squeezed and released the bottle &POOF! "clouds" appeared above the water surface. We were then give the chance to play around, squeezing and un-squeezing the bottle, watching the "clouds" form.
ANDthats CLOUD-MAKING

& SO
Why do we need to squeeze and release the bottle? for change in pressure
Why is smoke needed? condensation nuclei
How did the "clouds" form?.

In short, what was the experiment trying to show?
The ability of air to hold water depends on the temperature of the surroundings: the cooler the air the less water vapour is retained.
If warm air is cooled, it will become saturated with water vapour which will later condense in to liquid or ice water (e.g. water &ice-droplets).
HOWEVER water will NOT be able to condense spontaneuosly by itself. Minute particles in the atmosphere is needed which brings me to CONDENSATION NUCLEI. Water requires a surface to transit from a vapour to a liquid.

PICTURE THIS
Water vapor molecules is moving around at a FAST speed in air. For you to see "cloud" formation, the water vapour molecules have to collide &BIND together.
BUT now, at the speed that water vapour molecules are traveling, they tend to bounce off one another instead of bonding together.
condensation nuclei will then act as a platform for condensation to take place.

We also learnt about the forced uplit &free uplit.
FORCED UPLIFT
stable air forced to rise aboce relief barrier and ten to fall back toward lower level asap.
NO strong updraughts, collision process INEFFECTIVE
produces slight drizzle, hill fogs

FREE UPLIFT
unstable conditions
rising air continues to rise once triggered.
clouds may reach high in the atmosphere (temperature far below freezing)
both collision and icing takes place
HEAVY rainfall of high intensity

SEEDER clouds - high lvl clouds
High clouds are cirro-form clouds being composed mostly of ice. Generally found above 7000 meters, these clouds include: cirrus, cirrostratus and cirrocumulus.
GREAT rainfall intensity

FEEDER clouds - low lvl clouds
Low clouds are those that form from the surface up to 2,000 meters. Low clouds include: stratus, stratocumulus, and nimbostratus.

SIMIN(:

net radiation and planetary energy balance

Mathematical GEOG LESSON

During the last intriguing geography lesson, we learnt that our system is capable of balancing the amount of energy that enters Earth and the amount of energy that leaves Earth. We were given a task of calculating how the amounts balance up and it became mathematical.

The energy coming into Earth is from the Sun's short wave radiation.
Most of the sun's energy [100units] goes into the surface of Earth [51units], and the rest is either reflected back into space via Earth's albedo (reflected by: back scattering [6 units], clouds [20 units] and the Earth's surface itself [4 units]), or scattered at the atmosphere (which harbours clouds, aerosols [17 units] and the ozone layer [2 units]).

Earth's surface releases long wave radiation into the atmosphere via latent heat transfer [23 units], sensible heat transfer [7 units] and mostly emissions of long wave radiation [111units]. Earth's surface also emits long wave radiation directly into space [6 units].

The atmosphere emits long wave radiation directly into space [64 units], but most of it is absorbed into Earth's surface [96 units] by diffused and direct insolation and transferred into heat energy to be used by us.

The amount of long wave radiation that goes directly back into space from the Earth's surface and atmosphere, is equals to the amount of short wave radiation that goes into the Earth's surface and atmosphere from the sun.

The amount of radiation the atmosphere receives from the Sun's radiation and from Earth's surface, is equals to the amount of long wave radiation the atmosphere gives out into space and into Earth's surface.

This is very insightful as it shows that our system is able to naturally balance all its natural heat exchanges due to negative feedback that negates change (see last post), so the number of units of heat exchange between space, the atmosphere and earth's surface will change accordingly when more heat is produced at earth's surface due to human activities (produce greenhouse gases that traps heat in the atmosphere). But due to excessive human activities, global warming results because the planetary energy balance system is too overwhelmed to tip the system back into equilibrium through negative feedback. The result, earth gets warmer and warmer.

Huimin! :P

third geog lesson(:

At our third geography lesson, we learnt more about how systems in the Earth work together. Systems are made up of regulatory forces which will cause ngeative and positive feedbacks.


So what is negative feedback? (If you have forgotten about what we learnt in Biology last year, better cram this in your head now!) Negative feedback NEGATES change. So for example, if it gets too hot, you willl sweat and then you will cool down.


For positive feedback, it is just the opposite. It ENCOURAGES change. For example, if there's lots if water vapor in the air, more evaporation will take place, causing more water vapor. So if it is a bad condition, it will get worse in positve feedback.


For the second part of our lesson, we learnt about the CARBON CYCLE!


I've uploaded a draft copy of what Ms Lim had taught us. Next thing we have to do is to think about "how severe is man's impact on the carbon cycle". During the years, humans burnt too much fossil fuels, leading to an increase in CO2. We also deforestated too much of Earth in our way to urbanisation, and this also cause an increase in CO2.
Hope that everyone will have an idea of what they have to do for the essay. By the way, the deadline is extended to 16th feb (mon). Have fun people!:D
chailin

During today's geog lesson, Miss Lin showed us a video on the Earth's atmosphere. In short, it showed how the atmosphere was a contradiction. How it protects and helps us, yet poses a threat at the same time if its composition were to be changed.  For instance, the mesosphere protects us from meteors, by burning them up, while the stratosphere absorbs the sun’s harmful ultraviolet rays.  On the other hand, it could also cause tornadoes and lightning, threatening our lives. Is the atmosphere a friend, or a foe?

One of the highlights from the video, was the greenhouse gas, methane. It is ten times stronger than carbon dioxide in causing global warming. The video showed air bubbles containing methane trapped within the ice underground. The show host lighted a fire in one of the bubbles in the ice, igniting a huge flame, which was rather fascinating ^^. Not something you will see everyday... However, this is rather worrying, as great amounts of methane were present in the layer of ice. Imagine its effects on global warming, should the ice melt.

Through the video, I also realised how small we truly are. We live in the troposphere, the bottommost layer of the atmosphere. Being so adjusted to it, I never really tried to explore and understand the other layers above us. I was really amazed by Joe Kittinger, who flew up in a helium balloon alone, and travelled into the stratosphere- a layer above the troposphere, making a record in experiencing the longest free fall. Another man in the video, took the atmosphere to be his playground, and “surfed” in the air, while falling. He described the air around him as a fluid, which felt like a surface, and was able to do many incredible stunts.

To sum things up, I learned from today's lesson, that the atmosphere could be a both friend, and a foe. It is essential for our survival, yet it endangers our lives. Today's video, really intrigued me. Take a step back, and you will see that it has its beauty. From the aurora borealis, to the multi-coloured layers of iron oxide.

felicia =D