Geography. Козлова Е.П. - 89 стр.

1000C. The scale in between these points was divided into 100 equal degrees and was
called a Centigrade or the Celsius scale. The scale was simpler than Fahrenheit’s, and
was soon adopted by scientists throughout the world. In 1948 it became officially
known as the Celsius scale, which is now part of the International System of Units.
     Another temperature scale was made in 1848 by Scottish physicist William
Thomson-Lord Kelvin (1824 – 1907). Kelvin knew that when oxygen and other gases
were cooled, their volume became smaller. The lower the t0, the smaller the volume.
Experiments proved that at certain t0 the molecules do not move, and their energy
becomes zero. That represented the lowest possible temperature, and was called
absolute zero on the Kelvin temperature scale. On the Celsius scale absolute zero is -
273,15 0C.

                           17.7 Mountains that explode

      Since ancient times volcanoes have struck terror and awe into the heart of man:
but scientists tell us they do more good than harm. Many of the islands in the seas
and oceans have been thrown up by volcanoes. They have thrown up whole mountain
ranges too, some of which are very useful because they increase rainfall. The best
thing of all, however, is the way the lava from volcanoes enriches the soil. This
explains why farmers crowd the sides of volcanoes, risking death and destruction
from new eruptions. They can grow such good crops there that they think the risk
well worth while.
      Some volcanoes are dangerous. Of all the thousands and thousands of them
scattered about the earth, only about 500 are active. Perhaps not more than 50
volcanoes are erupting at this moment like Stromboli in the Mediterranean and Izalco
in El Salvador 1. Such volcanoes are watched by scientists. Most of the great volcanic
disasters have been caused by surprise outbursts from volcanoes which have not
erupted for so long that everyone imagines them to be quite harmless.
      In 1952, one of these, Mount Lamington, in New Guinea 2, erupted and caused
six thousand deaths. That disaster was bad but there have been much worse ones.
Think of Vesuvius which erupted in 79 A.D. burying the towns of Herculaneum and
Pompeii 3 under its ashes. Have you heard of Krakotoa 4? Thirty – six thousand lives
were lost when Krakotoa erupted, and the smoke and dust from the explosion was so
thick that it was blown right around the world.
      There is so much power in an exploding mountain that man can not attempt to
control it. But at least he is learning how to save himself from the volcano’s fury.
Scientists are studying volcanoes ways and learning how to tell in advance when they
are going to erupt. Thanks to scientists we are not so helpless as people were in
earlier days, when they were too often caught before they could even try to get away.




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