Glossary |
Select a letter from the index given below,
to be shown those glossary items which begin with the same letter.
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O |
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Occluded Fronts |
See Fronts (Occluded). |
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Offshore |
The coastal waters zone seaward of inshore waters. |
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Oxygen |
The second most abundant gas in air, comprising 21% by volume. It is a colourless
and odourless gas. |
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Ozone |
One of the several gases that make up the Earth's atmosphere. It is the triatomic*
form of oxygen and makes up approximately one part in three million of
all of the gases in the atmosphere. If all the ozone contained in the
atmosphere from the ground level up to a height of 60 km could be assembled
at the earth's surface, it would comprise a layer of gas only about 3
millimeters thick, and weigh some 3000 million tonnes. Ozone is toxic at
high concentrations because it reacts strongly with other molecules.
* Each ozone molecule
is made up of three oxygen atoms. |
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