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.