Theory: noun, plural theories.
A statement that explains observed observations
and predicts future observations. A theory is repeatedly
tested; if new observations do not agree with the stated theory then the theory
will be modified or replaced.
Examples:
Newton’s theory of gravitation which was replaced by Einstein’s upon further
observations.
Darwin’s theory of evolution which replaced those of Lamarck and others and has
been
modified through the study of genetics.
modified through the study of genetics.
Kepler’s theory of planetary motion which explains the orbits of planets and
allows
us to predict where new planets may be found.
us to predict where new planets may be found.
The germ theory of disease which replaced various superstitions concerning
the
cause of diseases.
cause of diseases.
The scientific theory of climate change explains the rapid
increase in the average temperature of the atmosphere and allows
the prediction of what will happen because of it.
From Earthguide.ucsd.edu |
As an example, my students learned (I hope) about how water
moves north and south in the oceans. The
start of the ocean currents is the freezing of the ocean in the arctic near Greenland. Only pure water freezes; the very salty and cold remainder sinks to
the bottom of the ocean. From there the
water travels south, cooling the tropical oceans as it goes.
The water finally reaches the Gulf of Mexico, where it flows
back along the surface to the arctic as the Gulf Stream. It is this warm Gulf Stream that keeps the
United Kingdom and northern Europe much warmer than it otherwise would be. In fact, Iceland is warmer in January than
Connecticut is.
The polar ice, then and now. From NASA |
An article published in Nature magazine (http://www.nature.com/nclimate/journal/v7/n8/full/nclimate3353.html)
indicates that the freezing up north is slowing down. Satellite image records indicate that
September Arctic sea ice is 30% less today than it was in 1979.
The obvious prediction is that when the arctic stops freezing,
the currents will stop exchanging cold water from the north with warm water
from the south and Europe will freeze. Yes,
“global warming” means that it will be colder
up north. Of course the ocean will also
be warmer at the equator (so we can predict more powerful hurricanes).
Science: it doesn’t only predict eclipses.
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