Script
Fulin Wang
[Show 01:02-01:09, 01:16-01:21 segment of Ozzy Ozone
http://www.youtube.com/watch?v=WKrPd-8CJBM] 14’’
The sun consists of hot plasma and releases many kinds of radiation. The radiations
are the source of the heat for the Earth. However, among the radiations of the sun,
ultraviolet, which is usually called UV, is harmful.
[Show 00:09-00:30 segment of The Antarctic Ozone Hole -- From Discovery to Recovery, a
Scientific Journey, http://www.youtube.com/watch?v=AU0eNa4GrgU
] 22’’
UV radiation could damage eyes. If your eyes are exposed to strong UV radiation for
a short period of time, your eyes may turn red, and you will have “a foreign body
sensation and gritty feeling in eyes” (About.com). That is a keratitis. If the exposure is
long-term, that will cause eye cataracts.
[Show 00:31-00:37 segment of The Antarctic Ozone Hole -- From Discovery to Recovery, a
Scientific Journey, http://www.youtube.com/watch?v=AU0eNa4GrgU
] 7’’
Exposure to too much UV radiation could result in damage to DNA. (Several genes
associated with skin cancer could be mutagenized.) Under excessive amounts of UV,
skin cancer would be widely spread.
[Show 00:37-00:47 segment of The Antarctic Ozone Hole -- From Discovery to Recovery, a
Scientific Journey, http://www.youtube.com/watch?v=AU0eNa4GrgU
] 11’’
UV radiation causes deformed morphology for plants, such as changes in plant height
and leaf area. Animals also suffer the negative effects of UV radiation.
[Show 00:48-00:56 segment of The Antarctic Ozone Hole -- From Discovery to Recovery, a
Scientific Journey, http://www.youtube.com/watch?v=AU0eNa4GrgU
] 10’’
Fortunately, the Earth has an “umbrella” to protect itself from UV radiation. This
“umbrella” is the ozone layer.
[Show
Ozone Layer & Hole—Video for Kids
http://www.youtube.com/watch?v=u9ztDSbSrFI] 11’’
There are two layers of atmosphere on the Earth, the Tropo-sphere and the
Strato-sphere. The ozone layer is at the bottom of the Strato-sphere.
[Show
00:31-00:41
00:01-00:26
segment
of
segment
of
Ozone
Layer
Depletion
HD
http://www.youtube.com/watch?v=6QyI3Yo1sf4] 26’’
The ozone layer is 20-30 kilometers above the Earth. The thickness of the ozone layer,
usually several millimeters, depends on latitude and season. The solar intensity and
atmosphere circulation patterns affect its thickness. The ozone layer absorbs 91-99%
of the Sun’s UV radiation, like a shelter for the Earth.
[Show the picture of reaction] 15’’
With the energy of UV light, an ozone molecule would break into an oxygen molecule
and an oxygen atom. Then, the radiation is no longer harmful.
[Show
00:27-00:30
segment
of
Ozone
http://www.youtube.com/watch?v=6QyI3Yo1sf4] 3’’
However, the ozone layer is depleting.
Layer
Depletion
HD
[Show
00:32-00:40
segment
Layer
Depletion
HD
of
Ozone
http://www.youtube.com/watch?v=6QyI3Yo1sf4] 9’’
With audio
[Show the picture of molecular structures of CFCs] 9’’
Ozone layer depletion is caused by chlorofluorocarbons, which are usually called
CFCs.
[Show
01:19-01:28
segment
of
Ozone Layer & Hole—Video for Kids
http://www.youtube.com/watch?v=u9ztDSbSrFI] 12’’
Air conditioners, old refrigerators, fire extinguishers, spray cans, and so on are major
sources of CFCs.
[Show the picture of mechanisms] 50’’
The CFCs are stable below the Strato-sphere. However, when they reach the
Strato-phere, the C-C bond breaks with the energy of UV light. The free chloride
radical is made as the first reaction shows. The free radical contains a large amount
of energy. The chloride radical breaks down the ozone molecule. This whole process
creates oxygen but the free radical remains in the atmosphere and continues to work
in this way.
[Show
02:09-02:25
segment
of
Ozone
Layer
Depletion
HD
http://www.youtube.com/watch?v=6QyI3Yo1sf4] 17’’
Due to the low temperature at the Antarctic, CFCs condense in this area. The
depletion is harsher here, and then the Antarctic Ozone Hole appears.
[Show
00:01-00:56
segment
of
Discovery
http://www.youtube.com/watch?v=7QGD-KiqKdE] 56’’
With audio
of
the
Ozone
Hole
[Show 01:25-02:12 segment of Science Bulletins: Ozone’s Slow Recovery
http://www.youtube.com/watch?v=bZWrSr7c09k] 47’’
With audio
[Show “Thank You!””Edited by Fulin Wang”]