If Macritchie Reservoir has a depth of 2.5m during the dry season,estimate the amount of water.

We have 2 methods of finding the answer.

Method 1: Remember how to find the area of a cirlce? Yes, we use that method.

Radius=125cm
H=15oooocm
pie=3.14
v=3.14 x 15oooo x 125 x 125
=7359375 thousand ml





But there is a flaw in this, here is a diagram of the flaw that i have mentioned.




There is of course another method in which u could divide in 2 but that would make the rest of the calculation go awry.

Method 2:perhaps a more easier method would be the length x breadth x height method.






length=120000cm
breadth=84000cm
height=250cm
volume=120000 x 84000 x 250cm
=2520000000000cm3
=2520000000000ml


There is a great difference between these 2 methods. if u truly want to know how much water there is in Matritchie Reservoir, i suggest you slowly scoop up all the water in the Rreservoir.
(Beware: you may want to try this but what if it rains after you have scoop up about half of the reservoir? ;D)

Rachel~

Regarding the previous post,please post your thoughts under 'comments'. A friend of mine has done so. Likewise, i look forward to your views. Thanks

In a submarine, there is a device called ballast tank. A ballast tank is a type of machine that has a pump and a few other machines. The pump is the most essential part of the ballast tank. For a submarine to sink. the pump will 'suck'in water, and air will be forced out, increrasing density and weight and thus sinking.to float back up, the pump, instead of taking in water, takes in air and water wil thus be given out.This is a picture of a ballast tank and how it floats and sinks.

During a journey, the submarine must maintain the same amount of composition of water and air. This is called nuetral buoyancy.


This is a diagram of a submarine.It shows all the machines in a submarine.












A Submarine HIstory
submarine name:kursk

Work on building the Kursk began in 1992 at Severodvinsk, near Arkhangelsk. Launched in 1994, it was commissioned in December of that year. It was the last of the large Oscar-II class submarines to be designed and approved in the Soviet era. At 154m long and four stories high it was the largest attack submarine ever built. The outer hull, made of high-nickel, high-chrome content steel 8.5 mm thick, had exceptionally good resistance to corrosion and a weak magnetic signature which helped prevent detection by Magnetic Anomaly Detection (MAD) systems. There was a two-metre gap to the 50.8 mm thick steel inner hull.It was indeed an maginficent submarine.

Unfortunatly,tragedy struck.An explosion occurred while the Kursk was preparing to fire Dummy Torpedoes.The only credible report to date is that this was due to the failure and explosion of one of the Kursk's hydrogen peroxide-fuelled torpedoes. It is believed that HTP, a form of highly concentrated hydrogen peroxide used as propellant for the torpedo, seeped through rust in the torpedo casing.

It is also believed that a chemical cartridge ( potassium superoxide), had also been the cause of death. It came in contact with the water that had caused chemical reactions and flash fire.

Which of these really happened? No one knows for sure.

However, a second explosion occured, reading 3.5-4.4 on the Ritcher Scale.


Fortunately, 23 sailors out of 118 sailors had survived the first explosion. Captain Lieutenant Dmitry Kolesnikov, one of the survivors of the first explosion, had written notes about his stay and confirmed there were other people with him as well.The rest died in the next explosion that happened a few hours later.

The world was shaken when they had heard this devastating news.But it has already happened. We can only remember those brave people in our hearts.

My condolences.



Question Alert 1:If a submarine lands on the seabed, why is it unable to float and move once more?

My answer is that maybe when the submarine has reached the seabed, the propeller has been crushed in the process. But that seems highly unlikely as i doubt it happens everytime.

Please give me your thoughts for Question Alert 1. Gracias~

29 jan 09: Mr Lim had said the submarine moved by thrusting forward. As the seabed is rough, the submarine cannot move and so the upward thrust cannot be used.

Rachel

Hey everyone, my name is rachel. ^^ i hope we can learn from one another and not be selfish about sharing information.(i tend to be very greedy when it comes to knowledge. i'll suck up all the words XD)

The most exciting phrase to hear in science, the one that heralds the most discoveries, is not "Eureka!" (I found it!) but "That's funny..." ~Isaac Asimov

A fact is a simple statement that everyone believes. It is innocent, unless found guilty. A hypothesis is a novel suggestion that no one wants to believe. It is guilty, until found effective. ~Edward Teller

Men love to wonder, and that is the seed of science. ~Ralph Waldo Emerson

science is not about sitting in a classroom and listening to the teacher droning on and on and all the information goes into one ear and comes out the other.

science is when someone wants to explore and learn more, the definition of life and beyond. i do not believe in the human who says :'i do not know science'. after all, we are looking at science everyday. you see a plant and think :'its just a plant.' No. think of it this way:"wat makes a seed grow? wats its life like?" the human mind must ask questions, only then can we truly call ourselves scientist. Wonder and learn, my friends~

What a distressing contrast there is between the radiant intelligent of a child and the feeble mentality of the average adult.