Rain-Making

Clouds in the air, even those big ans full of water vapour, do not help the farmers whose fields need rain, or the city people whose reservoirs are running low. To be of use, the clouds must become rain. Scientists think that clouds can be turned into rain if provided with more particles around which the rain drops can form.

All kinds of particles have been tried for artificial rain-making. One kind that seems to work is a chemical called silver iodide. Small particles of this chemical can be scattered from an airplane. They can spread very well among the particles of water vapour, so that only a small amount of this harmless chemical can help a large cloud to form rain drops.

Besides, dry ice can be used. Clouds can be cooled and possibly “dusted” by scattering bits of these crystals from a plane. The dry ice breaks up into cold crystals around which water vapour can cool and condense.

Of course, artificial rain-making will not work on every cloud. It seems to work only on clouds that need a little push, that are almost cool enough ot that have almost enough dust. But further experiments are being tried all the time, and some day it will be possible to have rainfall from any cloud, whenever we need it.

Dry ice can be used to start a chain reaction that will release a great deal of energy from hurricane clouds and so control the farm centres. Perhaps it will be able to force rain by cloud seeding at an early stage in the life of a hurricane and thus prevent the formation of the storm.

Although some scientists are very enthusiastic about cloud seeding with dry ice and a chemical known as silver iodide, others say such actions do not really change the weather. Some farmers consider that new methods of increasing rain are not producing the results needed. Cloud seeding holds great promise. So, there is good reason to believe that man may some day prevent hail and storms which produce crop damage, as well as increase rain supply to certain areas.

Date: 2015-10-19; view: 304; Нарушение авторских прав