What objects will have
a gravitational
attraction to the Earth?
Which one has a
greater gravitational
pull on the Earth’s
tides?
Why does the moon
have a greater
gravitational pull on
the Earth’s tides?

Because it is closer to
the Earth!
The moon exerts a
gravitational pull on
the Earth that causes
the oceans to rise and
fall.
The rise and fall of
the oceans are called
The moon’s
gravitational pull
causes the oceans
to bulge.
Bulging of the oceans
The oceans
bulge in two
places:
• The side of the
  Earth facing the
  moon.
•The side of the
Earth
  facing away from
Each of these bulges
causes a high tide.
At the same time, low
tides occur between
the two bulges.
The high tides ALWAYS
follow the moon.
The difference between
the level of ocean water
at high and low tide is
How many high tides
and low tides occur
each day?
How long does it take
for the Earth to rotate
once on its axis?
How many hours are
there between a high
tide and a low tide?
How many hours are
there between two
high tides?
At any given time of
the day, how many
high tides are there?
High tides that are
higher than normal
are called
This also means that
the low tide is lower
than normal during a
spring tide.
Spring Tides occur
during the Full Moon
and New Moon phases.
The gravitational pull of
the sun and moon are
combined together
since the sun, Earth and
moon are in a straight
line.
High tides that are
lower than usual are
called
This means that the
high tides are not very
high and the low tides
are not very low.
Neap Tides occur during
the First and Last Quarter
Moon phases.
This means that the
moon’s gravitational
pull is partially
cancelled out by the
sun’s gravitational
pull.

Tides notes ppt