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"For many people--perhaps for most--the word 'wave' conjures up a picture of an ocean,
with the rollers sweeping onto the beach from the open sea. If you have stood and watched this
phenomenon, you may have felt that for all its grandeur it contains an element of anticlimax. You
see the crests racing in, you get a sense of the massive assault by the water on the land--and indeed
the waves can do great damage, which means that they are carriers of energy--but yet when it is all
over, when the wave has reared and broken, the water is scarcely any further up the beach than it
was before. That onward rush was not to any significant extent a bodily motion of the water. The
long waves of the open sea (known as the swell) travel fast and far. Waves reaching the California
coast have been traced to origins in South Pacific storms more than 7000 miles away, and have
traversed this distance at a speed of 40 mph or more. Clearly the sea itself has not traveled in this
spectacular way; it has simply played the role of the agent by which a certain effect is transmitted.
And here we see the essential feature of what is called wave motion. A condition of some kind is
transmitted from one place to another by means of a medium, but the medium itself is not
transported. A local effect can be linked to a distant cause, and there is a time lag between cause
and effect that depends on the properties of the medium and finds its expression in the velocity of
the wave. All material media--solids, liquids, and gases--can carry energy and information by
means of waves."
2. (2 pts) What does the word wave mean to you? In your own words, give a description of wave
motion.
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