Students
started class by going over safety rules and procedures with a
pictorial challenge. Afterwards students took the safety test. Today in
class we discussed waves, powered by wind, and their parts. 
We
also discussed tsunamis, which fascinate most students. Tsunamis are
caused by underwater earthquakes and they displace water. Displacement
of water causes a large wave or energy to travel through the water, but
it cannot be seen at the surface until the wave approaches shallow
water. (Confused? Check out the diagram to the left) Because the wave is
not felt in deep water, going out to sea is one option for escaping a
tsunami, getting onto land with higher elevation is another option.
There are places in Japan and Hawaii where fishermen went out to sea in
the morning and when they returned, their villages had been washed away.
Next
we discussed tides. Tides are caused by the moon's gravitational pull
on the ocean. The sun has an impact too, but the moon's impact is
greater because it is a lot closer. The ocean water bulges towards the
moon and causes the high tide... areas perpendicular to the bulge are
having a low tide. Because the earth is rotating, each place is going to
have two high tides and two low tides each day.Spring high tides are
exceptionally high and really really low when the earth, sun, and moon
are all lined up in a row.
We
finished class by discussing temperature and locations on the globe and
watched some Blue Planet on tides, tidal bores, sand bubbler crabs that
comb through sand eating macro-organisms, and bears that eat clams.
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