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Is
there ever "too much" sunlight in Oregon?
An
Investigation into Ultra-Violet Radiation,
by Susan K. Cowles, Oregon Weather Project, OASIS,
1998
(when
this was written in May 1998, the state set
all-time rainfall records, breaking the record set
in 1896)
There are times in
Oregon when it seems that the sun never shines.
Does that mean that Oregonians are spared the
effects of too much sunlight? Let's
investigate.
The sun produces
many kinds of radiation in addition to what we can
see as visible light. To see information about The
Solar Spectrum of Light, visit these links....
http://imagine.gsfc.nasa.gov/docs/science/how_l1/spectra.html
http://imagine.gsfc.nasa.gov/docs/teachers/lessons/roygbiv/spectrum.html
http://imagine.gsfc.nasa.gov/docs/introduction/emsurface.html
One kind of
sunlight is known as ultraviolet radiation, and one
type of this radiation is called UVB. This is light
that is not visible to humans, but it still can be
dangerous. There are many harmful effects of UVB,
including skin cancer and eye cataracts in humans.
This light may also damage other animals on Earth,
especially those living in the world's oceans. Some
crops may be damaged by UVB light also.
There is a layer of
ozone lying 10-25 miles above the Earth's surface.
This ozone layer protects the Earth against most of
the UVB coming from the sun. Unfortunately, the
ozone layer is being depleted, so harmful effects
of UVB may be on the increase.
The amount of UVB
radiation is greatest on clear days when the sun is
high in the sky. However, UVB is reflected by
water, sand, and snow. UVB can reflect off the
sides of some types of clouds, making UVB levels
high near the ground, even on a cloudy day. So, do
we need to worry about UVB? How do we know when we
are getting too much UVB? Is this possible in
Oregon? Here are several activities that are
designed to explore these questions.
Activity 1:
Using
the UV Index
Activity 2:
Comparing
U.S. cities: looking at data from 1996 and
1997
Activity 3:
What's
the best month to be outside??
(data analysis)
Activity 4:
Scenarios
- Protect Your Family from UVB Radiation
UVB
Activity 5:
Comparing
Oregon to Australia and New Zealand
Activity 6: Check
your knowledge with a UV Radiation Crossword Puzzle
from the Environmental Protection Agency:
http://www.epa.gov/docs/ozone/puzzles/uvpuzzlp.html
Activity 7: Take a
quiz on Skin Cancer Risk Factors from Science News
Online:
http://www.sciencenews.org/sn_arc98/6_6_98/bobextra.htm
Click
here for this lesson's "Notes to
Instructors"
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