Video Transcript
Why is the ozone layer essential to
surface-dwelling life on Earth? (A) The ozone layer allows clouds
to form as part of the water cycle. (B) The ozone layer provides a
weather-free zone for aircraft to fly through. (C) The ozone layer acts as a
shield preventing meteors from hitting the surface of Earth. (D) The ozone layer helps birds
navigate during their yearly migrations. (E) The ozone layer filters out
harmful UV rays from the Sun.
The Earth’s atmosphere is composed
of several layers. The troposphere is the closest
layer to Earth in the atmosphere and it extends to a height of about 10
kilometers. The next layer is called the
stratosphere, and this extends to a height of about 50 kilometers.
Ozone is a gas that is found in
highest concentrations in the ozone layer, which is located within the stratosphere
at a height of between 20 kilometers and 40 kilometers from the Earth’s surface. The ozone layer is exposed to
harmful ultraviolet radiation that reaches Earth from the Sun. The ozone gas absorbs some of this
harmful radiation produced by the Sun. When it reaches the ozone layer,
the intensity of very-short-wavelength radiation is reduced completely. This short-wavelength UV radiation
is known as UV-C radiation. It is the most dangerous of the UV
rays, and 100 percent of it is absorbed by the ozone layer.
The ozone layer absorbs about 95
percent of medium-wavelength UV radiation. This type of UV, also known as UV-B
radiation, can cause sunburn and skin cancer. The ozone layer absorbs only five
percent of the longer wavelength UV radiation known as UV-A. This is the least damaging of the
UV rays. The ozone layer is therefore very
effective at absorbing harmful UV radiation that would otherwise cause severe damage
to life on the surface of the Earth.
The answer to the question “Why is
the ozone layer essential to surface-dwelling life on Earth?” is the ozone layer
filters out harmful UV rays from the Sun.
