Man's physical universe

xanabras

UNIT IV

SECTION 8

SCIENTIFIC WEATHER-FORECASTING IS AN EXCEL-

LENT EXAMPLE OF THE APPLICATION OF THE

SCIENTIFIC METHOD

The belief that nature is orderly is not yet universal.

Savages, we are told,

live in a completely capricious universe, and we still find congregations praying

for rain although they would hesitate, probably, to pray that the sun might

stand still. That is because astronomy is a more developed science than

meteorology. — J. W. N. Sullivan.^

Introduction.

Man has little control of atmospheric conditions beyond the air

conditioning of his buildings and trains, but he has learned how to

predict the weather fairly accurately for one to two days in advance.

In 1940, the United States Weather Bureau launched five-day weather

forecasts, issuing them twice a week from ten district headquarters.

Weather prediction involves the consideration of so many variable

factors and such a large number of observations that it is not at all

exact.

,

Many Observations Must Be Made for Weather Prediction.

At the United States Weather Bureau stations, maximum- and minimum-temperature

readings are a part of the regular observational

routine. The maximum thermometer is like the ordinary kind except

that a constriction near the bulb end prevents the mercury from going

back to its bulb after it has risen. Just as a clinical thermometer, it

must be reset by whirling. The minimum thermometer contains alcohol

instead of mercury, and it is kept in a nearly horizontal position. As

the alcohol recedes with a falling temperature, a little dumbbellshaped

index is carried down with it. Since this index is not carried

upward when the alcohol expands, the point where the index is

located indicates the lowest temperature reached since the time when

the thermometer was last set.

' The Limitations of Science, The Viking Press, New York, 1934, p. 284.

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