Tides
How They Work and Why They
Are So Important
Beatrix Hutton
2005
A Basic Definition
• Alternating
rising and
falling of water
due to the
position of the
Sun and the
moon and the
earth.
How Tides are Formed:
High Tides
• Are formed
when the moon
is facing the
water and pulls
the water
upward
Parallel Universe
• A high tide is
formed and a high
tide is formed at
the exact
opposite side of
the earth.
• This is caused by
earth’s rotation.
In The Middle
• Between the 2
high tides two
low tides are
formed.
• This is
repeating
constantly
around the
world
Spring Tides
• Are stronger and bigger than other
tides
• ocean rises to full capacity
• formed when the sun and moon line
up with earth
Neap Tides
• Are smaller and weaker than other tides
• they are weaker than other tides
because the moon’s attracting force is
partly canceled out
At the Beach
• At most beaches
and lakes there
are two tidal
cycles
• high tide and low
tide =tidal cycle
• 2 tidal cycles
=semidiurnal
Diurnal Tides
• In a few places
there is only one
tidal cycle
• these are called
diurnal tides
Falling and Rising Tides
• There are several
other tides
• rising tides=flood
tides
• falling tides=ebb
tides
• lowest point at low
tide and highest point
at high tide =slack
tide
Longshore Drift
• Long shore drift is
a strong current
of water than runs
almost parallel to
shore
• it can go in one
way or another
depending on the
wind
Riptides
• Riptides are a fast
moving water
current
• the Long shore
drift combines
with the angle the
ocean hit the
beach to produce
riptides
What to do if you are caught in
a Riptide
• The rip current can
push you out if you
are not careful.
• If you are ever
caught in a rip tide
you should swim
with the current until
you are free of the
current. Then you
can swim back to
shore.
Beach Erosion
• Tides cause a lot
of erosion
• If nothing keeps
the sand in place
it will completely
wash away
Xtreme Places
• The Bay of Fundy
has the largest
tidal ranges in the
world
• it has a range of
50 ft while most
beaches only have
a range of 5 of 6
feet
Newton and Tides
• Until the 19th
century the only
way used to
explain tides was
Newton’s laws
• Newton did not do
much work with
tides
Solar Tides and Lunar Tides
• Lunar, Moon,
tides are stronger
than Solar, Sun,
tides because the
moon is so much
closer to the earth
even though it is
much smaller
than the sun.
Extra Info
• Every 14 days
spring tides are
produced
• 7 days later neap
tides take place
Bibliography
• No Author mentioned.Scholastic Atlas of
Oceans. QA International. Montreal.
2004.pgs. 40-41.
• K. Lee Lerner and Brenda Wilmoth Lerner. U
X L Encyclopedia of Water Science. Volume 1
• Information and Facts on Ocean Tides. No
author given. The time last updated not
given.Accessed 5/19. At
<http.//gometaldetecting.com/oceantides.html>
Bibliography continued
• No author given. Tides. Accessed 4/29/05. Last
updated 2005.
<http://geography.about.com/od/physical
geography/a/tides.htm>
• Tides. U X L Encyclopedia of Science.2nd
edition.U X L.2002 Junior Reference
Collection. Thomson Cale.
4/29/05.<http://galenet.galegroup.com/servlet/J
RC>
About the Author
Hi, my name is Beatrix
Hutton. I always liked
science and I really love
marine biology. The trip
to the Florida Keys
really made me
interested in the ocean.
Since I learned to
snorkel there I have
been trying to learn
more about the ocean
and the animals living
there. I think that I might
consider a job in marine
biology after I graduate
from college.