Today I had my OC presentation. Which by the horrors was followed by a quiz later. My mind was with so much madness. Heres the speech I prepared...
Good morning mr seto and fellow classmates, I am Lim Yok Zuan. Thank you
everyone for giving us presenters today ur attention, eventhough there is a quiz
later. On behalf of all the presenters today, I Thank you.
There is a nursery rhyme that goes like this, “twinkle twinkle little star, how I wonder
what u are.” You knw I remb when I was very young, after I listen to this
nursery rhyme, I ask my father. “ah pa, what is a star?” and he replied, “siao
ah, a star is a star la, ask stupid qns!”. So today, I will tell u ALL about
STARS.
(Click)
Do u knw that each time u look up into the sky and see a
star, u are actually looking deep into the history of our universe? Because
stars are so far away, light takes 1000s even millions of years to travel from
there to here. So what u see each time u look at the bright dot in the sky is
actually things that already happened 1000s and millions of years
ago.
(click)
Stars are so far away, yet they play a very significant role
in our existence. Today I will be telling u abt the life of stars, how stars
begin, how they live and eventually, how they may die.
(click)
In space there is a lot of hydrogen. Stars form when a critical mass of hydrogen clouds
in space get squeezed together by gravity so close that thermonuclear fusion
takes place. The hydrogen atoms fuse to become helium. This fusion of hydrogen
into helium releases huge amounts of energy in the process. This is why a star
shines. As long as the chain reaction is sustained, A STAR IS
BORN!
(click)
But it doesn’t stop here. As the star use hydrogen, it makes
helium. When it runs out of hydrogen, the core shrinks as it is no longer hot
enough to hold against gravity. It then collapses until the core becomes compact
enough for Helium to fuse, this time into carbon and oxygen. But even helium
runs out, now carbon and oxygen start to fuse into silicon and neon and so on
and so forth (click). As this animation shows, each time it collapses to fuse
new elements, it releases a sudden burst of energy that blasts off some of its
surface; the cycle repeats until eventually iron is formed in the core of the
star. Iron simply cannot fuse into other elements.
(click)
But even the iron core itself eventually collapses. What happens next is spectacular! Imagine
in less than a second it collapses from the size of 8,000 km wide to become only
20km wide. This Releases a sudden enormous amount of energy. I knw this is
getting hard to imagine so let me show u an animation of this (click). U cant
see the core here, but the core actually shrinks, and releases a huge wall of
energy, equivalent to 100 suns burning for 10billion years in this split second!
This energy slams into the outer layer. And the entire outer layer of the star
literally explodes from the core!! It is in this explosion that trace element
heavier than iron are formed. This event is known as a
supernova.
(click)
Some stars are supermassive. With hundreds even thousands times the mass of normal stars. In this case something even more spectacular happens! Such stars because they are so big they collapse so fast under their own weight, that these dying stars release an incredible burst of
energy, so much energy, equivalent to our Sun 880 billion years, in a single
terrible blast (click for GRB!) known as the gamma ray burst. In this brief
moment, the dying star becomes the brightest thing in the universe. What remains
of the once bright star now becomes a black hole.
(click)
What happens if such an event were to occur near earth? If a gamma ray burst were to occur near
earth, what we will see is the skies suddenly turn bright blue. Then the seas
would boil and the land become as fire. GRB are pretty much the ultimate
sterilant of our universe. And it has happen b4. 500 million years ago, a GRB
occured 6,000 light-years away from Earth. That is 5.7x1017 km away. So far
away. Yet 60% of all life on earth was extinguished. The event is known as the
Ordovician mass extinction.
(click)
I have talked abt how stars are made as the result of the thermonuclear fusion of simple elements into complex elements. Look around u, everything u see, everything you knw, your hands, ur
table tennis ball, your brain, ur fav canoe, elephants, rabbits. Everything is
made from atoms and elements. And what made these elements are the furnaces in
the sky. They came from stars! Lastly I hav also talked abt how stars will
eventually die. Possibly with a catastrophic bang.
We owe our
existence to the stars. For those of us who wonder why we exist, rather than
look down into a microscope, try looking up into a telescope instead. I hope the
next time u look into a star, u remb that there is something in common between u
and these stars in the sky, because we too are made from stardust. And chances
are, all of us and everything on earth once came from the same twinkle twinkle
little star. Next time your children ask you, “what are stars?”… I hope you will
my presentation today.
(click)
Now is the time for me to address your questions. Any questions from the floor?
The presentation went ok… but unfortunately, I didn’t get the grade I was hoping for. Oh well…
Then there was the quiz…madness… I am gonna hate seeing the score for that one…
Back home my mind gave up on me and I feel asleep like never before. I didn’t even know where I was when I woke up. I had dreams so vivid… so long since I last even had any dreams. Such deep sleep… oOoOo
