Definition: Tides
The regular rising and falling of
seawater resulting from the
gravitational attraction between
the Earth, Sun, and Moon.
http://www.pbs.org/wgbh/nova/venice/tides.html
Definition: Spring Tide
Extreme high and low tides that occur
about twice a month, caused when the
sun and the moon pull in the same
direction
Definition: Neap Tides
Smaller high and
smaller low tides that
occur about twice a
month, resulting from
the earth and sun
being arranged at right
angles to one another
• http://www.asccsa.gc.ca/eng/educators/resources/astron
omy/multimedia/module3/tides/tides.swf
Tidal Range
– difference between low tide and high tide
– usually about 1 meter
– can be as little as ½ meter or as much as 20
meters
– influenced by the shape of coastline, shape of
ocean floor, and depth of coastal water
High and Low tides
Bay of Fundy high and low tide
High and low tides
NOAA Rainier
Low tide in Homer, Alaska
High tide in Homer, Alaska
Figure out the Tidal Range!
When were the two photos of the
ship taken?
The tide comes in at
Kachemak Bay, Alaska.
The tide goes out at
Kachemak Bay, Alaska!
PONTOON