What Are Tides? What Causes Tides? YouTube Lecture Handouts

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What are Tides? What Causes Tides?

What Are Tides?

Tides are the daily rise and fall of Earth՚s water on its coastlines.

Tides occur in all bodies of water but they are most noticeable in the ocean and large lakes.

Caused by the interaction of Earth, Moon and Sun.

Gravity is the reason for tides.

Illustration: What Are Tides?
Illustration: What Are Tides?

Tide-Generating Force

Tide-Generating Force of the Sun

NOTE: The sun has 27 million times more mass than the moon and is 390 times farther away from the earth than the moon.

So …

Therefore the Sun has 46% of the tide-generating force of the Moon.

Illustration: What Are Tides?

Declination of Earth

Illustration: Declination of Earth

High Tide and Low Tide Animation

Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of Earth. Some places have semi-diurnal tide — two nearly equal high and low tides each day. Other locations witness diurnal tide - only one high and low tide each day. A “mixed tide” has two uneven tides a day, or one high and one low.

Illustration: High Tide and Low Tide Animation

Spring Tide

Illustration: Spring Tide

Manishika