Swing Bowling
HOW DOES A BALL
SWING IN AIR??
In a cricket-frenzy country
like India, cricket lives in almost every street of the country. Every fast
bowler wishes to master swing bowling, and would love to see his delivery
baffling the batsman. Ever wondered how swing bowling actually occurs? How is
it that the ball just swirls around in the air as if it is magically controlled
by the bowler? What are the techniques followed?
Nuclear Bombs
On 6
August, 1945 the city of Hiroshima in Japan experienced the horrors of nuclear
warfare for the first time in the history of the world. And 3 days later on
August 9, the city of Nagasaki was razed to the ground by yet another nuclear
bomb. The bombings brought Japan to its knees and ended the Second World War
A
nuclear weapon is a destructive weapon that derives energy from a thermonuclear
reaction. It uses the energy taken from the nuclei of atoms and transforms it
to incredible amounts of heat and light. There are two main types of nuclear
bombs, namely nuclear fission bombs and nuclear fusion bombs. Nuclear fission
bombs were the types of bombs dropped on the Japanese cities of Hiroshima and
Nagasaki. The nuclear fusion bombs were developed much later and are much more
powerful than fission bombs. These have never been used in warfare. It is said
that one fusion bomb is equivalent in destructive capacity to around 700
fission bombs. The fusion bombs are also called hydrogen bombs.
Though both the fusion and fission bombs are called nuclear bombs, they
both follow two different processes. The nuclear fission bombs are based on the
principle of (no prizes for guessing ;-) nuclear fission while the fusion bombs
use the principle of nuclear fusion.
Fission is the process
of splitting up of a large nucleus into two or more smaller nuclei on the
impact of an energetic neutron. This is accompanied by the release of extremely
high amounts of energy. Generally a uranium nucleus is used in fission bombs.
When the nucleus is bombarded by a neutron, it breaks into two nuclei, one
Krypton and one Barium nucleus along with the release of three more neutrons.
Each neutron in turn splits up a uranium atom. This results in an uncontrolled
chain reaction culminating in a catastrophic explosion.
Nuclear fusion on the other hand involves the fusing of a deuterium
nucleus and a tritium nucleus to give a
helium nucleus accompanied by a free neutron. This releases a much higher
amount of energy than nuclear fission. But nuclear fusion is much tougher to
attain on earth because the activation temperature for this reaction can only
be attained by means of a nuclear fission reaction. The sun releases all its
energy due to nuclear fusion reactions of hydrogen to form helium.
Now,
we come to the question of the mushroom cloud, the worldwide symbol of horror
connected to the nuclear bomb. Why does this mushroom cloud form?
When
the bomb detonates at ground level, the surrounding areas of up to 3 kilometre
radius are vaporised due to the heat of explosion. The resulting hot gases and
debris become lighter than the surrounding air and rise up at an extremely high
speed . This forms the stem of the mushroom. Then as the speed of the hot gases
slows down, they expand outward slowly thus giving rise to the shape of a
mushroom. The mushroom head stops expanding when it reaches a height where its
density is equal to the density of the surrounding air.
On a historical note, nuclear bombs were an important factor in
escalating tensions between the United States of America and the USSR during
the Cold War. Both the countries constantly threatened to “display” their
nuclear power to the other country, throwing the whole world into confusion,
because if there is any sure shot method to destroy all human civilisations on
the Earth, nuclear war is the way. Presently all countries are following
processes of decreasing their nuclear arsenal.
Why am i saying that a nuclear war will destroy the world? Experts have
conducted extensive research and found out what will happen in case of a
nuclear war. If a sufficiently large amount of nuclear bombs (around 50) are
detonated around the world, the huge fires following the nuclear explosions
will lift enormous amounts of ash into the atmosphere. This will block most of
the sunlight from reaching the earth’s surface and thus kill all the plants
which are dependent on sunlight for their daily food. When all the plants die,
the whole ecosystem collapses because all animals directly or indirectly depend
on plants for sustenance. The global temperatures will drop, plunging the
earth’s fragile ecosystem into another ice age. Millions of people will die
from the explosions themselves and the unlucky ones who survive will have to
bear the horrible effects of radiation.
“And the living prayed for death “. This will be the situation in case
of a nuclear war. Thus we can see that nuclear weaponry is an extremely
dangerous tool and has to be governed responsibly. After all
WITH
GREAT POWER COMES GREAT RESPONSIBILITY!!!
BY
BHARAT, NSS VOLUNTEER
Submarine
Inertia
Why does a person sitting in a stationary
vehicle get pulled back when the vehicle starts moving?
In order
to understand this phenomenon you perform an experiment. Cover the mouth of a
glass tumbler with a piece of cardboard and place a coin on it. Now push the
cardboard with your finger so that the cardboard is thrown off the tumbler. Do
you know what would happen? Along with the cardboard the coin would also fall
off the glass. You should not worry and once again place the cardboard atop the
glass along with a coin. Now flick the cardboard forcefully with your
forefinger propelled with the help of your thumb and observe the consequences.
This time it would be quite different from
what happened earlier. As soon as you strike the cardboard it would be thrown
off but the coin would drop in the glass tumbler. What actually happens is
this; the cardboard is thrown off with such a force that the coin fails to
accompany the cardboard and the cause of the failure of the coin to move
together with the cardboard is law of inertia. When a thing is stationary it
remains in that stage till an external force makes it move. This is called Law
of inertia.
Fossils
Human beings have always tried to
know their past. We have always been interested in finding out what the earth
was like before we came into existence. But the past does not give up its
secrets easily. It is buried in the earth for all time in the form of fossils. From the in depth study of
fossils, we can gain important knowledge and evidence of life that existed in
ancient times. From the study of fossils, scientists have been able to even
find out the atmospheric conditions that existed in the distant past!!
Aurora Lights
The term “Aurora” basically refers to a
natural light at very high altitudes in the sky. The aurora borealis (the
Northern Lights) and the aurora australis (the Southern Lights) have always
fascinated mankind, and people even travel thousands of miles just to see the
brilliant light shows in the earth's atmosphere. The auroras, both surrounding
the north magnetic pole (aurora borealis) and south magnetic pole (aurora
australis) occur when highly charged electrons from the solar wind interact with
elements in the earth's atmosphere.