Reslless Energy
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into play by the Sun and Moon are extraordinarily slight, and even
when acting together would explain tides of only about two feet.
In 1774 the French mathematician Pierre Simon Laplace (1749—
1827) added to the theory with hydrodynamics—the science of
uids. He showed that although the Sun and Moon were the
driving forces, the behaviour of the liquid masses themselves were
also important. The tides could be compared with a child’s sw1ng
which the attraction of the Sun and the Moon gives two little pushes
every day to maintain its motion. Of course the nature of the ‘shove’
from outer space varies with the relative positions of the Sun, Moon
and Earth.
Superimposed on the basic pattern of the astronomical forces are
the complicating factors on the Earth itself. For example, the shape
of the ocean basins, the presence of the prevailing winds and the
land masses Which separate the major oceans, all play a part in
determining the tide. The tidal range in the open ocean, for example,
139
'
!'
into play by the Sun and Moon are extraordinarily slight, and even
when acting together would explain tides of only about two feet.
In 1774 the French mathematician Pierre Simon Laplace (1749—
1827) added to the theory with hydrodynamics—the science of
uids. He showed that although the Sun and Moon were the
driving forces, the behaviour of the liquid masses themselves were
also important. The tides could be compared with a child’s sw1ng
which the attraction of the Sun and the Moon gives two little pushes
every day to maintain its motion. Of course the nature of the ‘shove’
from outer space varies with the relative positions of the Sun, Moon
and Earth.
Superimposed on the basic pattern of the astronomical forces are
the complicating factors on the Earth itself. For example, the shape
of the ocean basins, the presence of the prevailing winds and the
land masses Which separate the major oceans, all play a part in
determining the tide. The tidal range in the open ocean, for example,