Why is the sky blue? Since the
atmosphere is more dense than space, the atmosphere acts
as a prism for the sunlight. Since shorter wavelengths
(like violet and blue) are refracted the most, the violet
is refracted at the top of the atmosphere, where we can't
see it. Next, the blue wavelengths are refracted, and
that is what we see when we look at the sky. The longer
wavelengths (green, yellow, orange, and red) reach us
before they can be refracted. Sometimes orange and red
can be seen around a sunrise or sunset, since during
sunrise and sunset, the sunlight that is reaching us, is
traveling a longer distance through the atmosphere and
has more time for refraction to occur.
At what wind speed, does a tropical storm qualify
to be called a hurricane? By definition, when a
tropical storm reaches wind speeds of 74 m.p.h. or
higher, it is no longer a tropical storm, but is a
hurricane.
What is drizzle? Drizzle is defined as
rain drops that are 1/16 of an inch or less in diameter.
Does global warming really exist? This
is a matter that has been debated for some time. While fluorocarbons are thought to have the potential to
deplete ozone in the ionosphere, it is also known that
ozone replenishes itself naturally. Records of
temperatures have been kept consistently for over 100
years. If we look at these records, we find that cycles
of warming, and cycles of cooling occur, but that
overall, the temperature of the earth has remained
essentially the same.
How does lightning occur? In a thunder
cloud, the up and down movement of particles in the cloud
causes the lighter, usually positive particles, to go to
the top of the cloud, and the heavier, usually negative
particles, to the base of the cloud. There are three
kinds of lightning that can occur.
Intra-cloud lightning, where the
lightning goes from the negatively charged
particles at the base of a cloud, to the
positively charged area at the top of the same
cloud.
Inter-cloud lightning, where the
lightning goes from the negatively charged area
of one cloud to the positively charged area of
another cloud.
Cloud to ground or ground to cloud
lightning: Usually this lightning travels
from the negatively charged base of a cloud to a
positively charged tall object (such as a tree or
a barn) on the ground. It can also travel the
opposite direction, from a negatively charged
object on the ground to the positively charged
portion of the thunder cloud.
How do lightning rods work? Lightning
rods, which are usually mounted on top of a building or
other structure, have a cable going down to a grounding
rod, buried deeply into the ground. This provides a path,
for the lightning, safely into the ground, and protects
the structure. The tip of the lightning rod comes to a
small point. The lightning rod has a strong negative
charge due to the cable being buried deeply into the
ground. The small area of the pointed tip increases the
capacitance (charge per square area), of the end of the
lightning rod, which creates a strong attraction of the
lightning to the lightning rod, and away from the
structure being protected.
