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Clouds
Scientists
have studied cloud types and have realized that rain
clouds are formed and shaped according to definite systems and
certain steps connected with certain types of wind and clouds.
One
kind of rain cloud is the cumulonimbus cloud
associated with thunderstorms (See Figure 18.1). Meteorologists
have studied how cumulonimbus clouds are formed and how they
produce rain, hail, and lightning. They have found that
cumulonimbus cloud go through the following steps to produce
rain:
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The clouds are pushed by the wind: Cumulonimbus clouds begin to
form when wind pushes some small pieces of clouds (cumulus) to
an area where these clouds converge.
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Joining: Then the small clouds join together forming a
larger cloud.
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Stacking: When the small clouds join together, updrafts
within the larger cloud increase. The updrafts near the center
of the cloud are stronger than those near the edges. These
updrafts cause the cloud body to grow vertically, so the cloud
is stacked up. This vertical growth causes the cloud body to
stretch into cooler regions of the atmosphere where drops of
water and hail formulate and begin to grow larger and larger.
When these drops of water and hail become too heavy for the
updrafts to support them, they begin to fall from the cloud as
rain, hail, etc.
Allah
said in the Qur'aan:
Have you not seen how Allah
makes the clouds move gently, then joins them together, then
makes them into a stack, and then you see the rain come out of
it...? [Qur'aan 24:43]
Meteorologists
have only recently come to know these details of cloud formation,
structure, and function by using advanced equipment like planes,
satellites, computers, balloons, and the like to study winds and
its direction, to measure humidity and its variations, and to
determine the levels and variations of atmospheric pressure (See
Figure 18.2).
Fig.
18.1
Cumulonimbus
clouds seen from space
The
preceding verse, after mentioning clouds and rain, speaks about
hail and lightning:
And He sends down hail from mountains
(clouds) in the sky, and He strikes with it whomever He wills,
and turns it from whoever He wills. The vivid flash of its
lightning nearly blinds the sight. [Qur'aan 24:43]
Meteorologists
have found that these cumulonimbus clouds, that shower hail,
reach a height of 25,000 to 30,000 feet (4.7 to 5.7 miles), like
mountains, as the Qur'aan said: And He
sends down hail from mountains (clouds) in the sky...(Qur'an
24:43)
This
verse may raise a question. Why does the verse say ...its
lightning in reference to the hail?
Does
this mean that hail is the major factor in producing lightning?
Let us see what the book entitled Meteorology Today, says on
this. It says that clouds become electrified as hail falls
through a region in the cloud of super cooled droplets and
ice crystals. As liquid droplets collide with hail,
they freeze on contact and release latent heat. This keeps
the surface of the hail warmer than that of the surrounding ice
crystals.
When
the hail comes in contact with an ice crystal, an important
phenomenon occurs. Electrons flow from the colder object toward
the warmer object. Hence, the hail becomes negatively charged.
The same effect occurs when super cooled droplets come in contact
with a piece of hail and tiny splinters of positively charged
ice break off. These lighter, positively charged particles
are then carried to the upper part of the cloud by updrafts. The
hail, left with a negative charge, fall toward the bottom of the
cloud, thus the lower part of the cloud becomes negatively
charged. These negative charges are then discharged to the ground
as lightning. We conclude from this that hail is the major factor
in producing lightning.
Fig.
18.2
This
information on lightning was discovered only recently. Until 1600
A.D., Aristotle's ideas on meteorology were dominant. For
example, he said that the atmosphere contains two kinds of
exhalation, moist and dry. He also said that thunder is the
sound of the collision of the dry exhalation with the
neighboring clouds, and lightning is the inflaming and burning of
the dry exhalation with a thin and faint fire. These are some of
the ideas on meteorology that were dominant at the time of the
Qur'aan's revelation, fourteen centuries ago.
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