♥ Monday, March 9, 2009 ♥
I deeply apologise for this post being so late. anyway, what mr heah taught on friday was the 'fusion' of everything he taught for quite some time. it combines the knowledge the tilt of the earth at 23.5 degrees. as geographers studying physical geography, we want to explain why deserts are found at the tropics, and not the equator. logically if the earth was not tilted and there were no land masses and the earth did not turn, the people living around the equator (us) would be hot =D But, why are deserts found at the tropics and not at the equator where most sunlight is 'supposed' to strike the earth with the least surface area and the highest intensity. however, this is the real world we are living in, not some lala land where everything is at its ideal state. however, due to the fact that this is only secondary school level, we did not study the impact that land masses have on the climate and winds.
However, we studied the effect of the tilt of the earth had on the location of deserts. the tilt of the earth causes the areas near the north and south poles to experience 24 hours of night and day one day a year. we looked at the koppen-geiger map and realised that the location of deserts are at the places where the sun shines with the smallest surface area. also, we learnt about the definition of a desert, which is a dry land mass. we learnt about the three cell diagram, which is simply how air raises from the equator due to its heat, moves northwards, cools, and moves down. as air moves up, adiabatic cooling is allowed and hence causes rain. in the equator, it is wet due to the hadley cell pushing the air up and the presence of adiabatic cooling, which causes rain. however, at the tropics, the induced cell, also known as the ferrell cell, makes air move downwards instead of upwards. therefore, no adiabatic cooling occurs and therefore there is very little precipitation. this is the main explanation for the presence and location of deserts. there is also the polar cell, which is formed due to the absence of heat at the poles, which makes air sink and move to somewhere near the circles where they get warmed up slightly and rise again. the induced cell, as mentioned by him, is special because it is not formed by the heat, but by the movement of the air. the movement of the hadley cell and the polar cell causes the air at the tropics to move in a certain direction, therefore the use of the term 'induced' cell.
after that, mr heah took out a globe and taught us about the various kinds of data a globe could provide a reader with: the economic data, the population, the presence of land masses and many more. he also used the two bright suns to show what happens to the north and south pole during one day of the year, which i think is 21 of january and 21 of december. he used the globe to show us the essential points of what he taught throughout the whole term in diagram form. he also mentioned that at the equinoxes, there will be 12 hours of day and night ( spread out evenly)
lastly, before he left, he provided us with some information for the upcoming assessment week (heehee), telling us that we should know about the various housing estates in singapore as this is human geograhy that we are being tested on. he also recommended playing the 'geo challenge' game on facebook. the game has four parts. the first part requires you to match a country's flag to it. the second part requires the player to identify the countries from the shape of the country's land. in the third part, we are given the world map which from it, we have to identify different countries and parts of the coutries by clicking its location on the map itself. in the last part, we have to identify the countries from which different landmarks are at. it is a very interesting game and improved my geography too =D
Who wrote this?