Tides

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Tides

• Presented to Sir Mehtab Ahmad
• Presented by Group(A) Roll No 6151, 6152, 6153,
  6154, 6155,
• M.Sc Geography. 1st Semester

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Contents

• Definition
• Causes
• Theories
• Equilibrium Theory of Tides
• Dynamic Theory of Tides
• Types of Tides
• Effects of Tides

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Definition

• Tides are the cyclic rise and fall of sea levels
  caused by the combined effects of the
  gravitational forces applied by the moon and
  the sun and the rotation of the Earth.
• One low-tide/high-tide cycle takes about 12 hours
  and 25 minutes.

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Causes

• The gravity of the moon and the rotation of the
  earth causes the tides in Earth's oceans. The
  moon's gravity causes the ocean near to it to
  rise up and this rise up appears to sweep round
  the earth as the earth rotates.

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Theories
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Equilibrium Theory of Tides

• First developed by Newton stating that there is a
  bulge of water formed from the gravitational pull
  from the moon and centrifugal pull from the side
  opposing the moon. this explains most of the
  reasoning behind tides, but the main thing that
  it does not account for is that there are
  landmasses on earth that the bulge of water
  cannot move over.

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Dynamic Theory of Tides
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Types of Tides

• There are two major Types of Tides
• Spring Tides
• When the moon is full or new, the gravitational
  pull of the moon and sun are combined. At these
  times, the high tides are very high and the low
  tides are very low. This is known as a spring
  high tide. Spring tides are especially strong
  tides (they do not have anything to do with the
  season Spring). They occur when the Earth, the
  Sun, and the Moon are in a line. The
  gravitational forces of the Moon and the Sun both
  contribute to the tides. Spring tides occur
  during the full moon and the new moon. 

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Neap Tides

• During the moon's quarter phases the sun and
  moon work at right angles, causing the bulges to
  cancel each other. The result is a smaller
  difference between high and low tides and is
  known as a neap tide. Neap tides are especially
  weak tides. They occur when the gravitational
  forces of the Moon and the Sun are perpendicular
  to one another (with respect to the Earth). Neap
  tides occur during quarter moons.

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Types of Tides

• Spring Tides
• Neap Tides