The movement of the oceans tides can be seen clearly on our beaches.

1. Ocean tides are created by combining the gravitational pull of the moon and the sun, combined with the rotation of the earth. The moon’s gravitational pull is stronger than the suns which makes it the most important factor in creating tides.

2. The tides are really long-period waves that appear as the rise and fall of the sea as they reach the coastline . High tide is the crest of the long-period wave and low tide is the trough of the long-period wave.

3. The earth rotates on its axis once every 25 hours and the moon rotates around the earth once every 27 days. The moon pulls upwards on the ocean while the earth pulls down. This causes tidal movement.

4. Most places in the ocean experience two high tides and two low tides each day. There are places that experience only one each day. This is determined by the shape of the coastline and the shape of the ocean floor.

5. The tidal troughs are separated by about 12 hours. Because the moon rotates around the earth it’s not in the same place at the same time every day. So the high and low tide times changes every day by about 50 minutes.

6. Alignment of the earth, the moon and the sun cause the most gravitational pull resulting in maximum tides.

7. There are times during the moon’s rotation that it is on the same side of the earth as the sun. This occurs at the new moon and full moon phase. This results in larger tidal troughs. These are called Spring tides.

8. There are times in the moon’s rotation that it is at right angles to the earth sun line. This is at the first quarter and last quarter phase. This causes interference between the sun and the moon’s gravitational pull and results in weaker tidal troughs. These are called Neap Tides.

9. The lowest tide height difference occurs out in the deepest part of the ocean at approximately 1.6 feet.

10. The highest tide height difference in the world is in the Bay of Fundy in Nova Scotia, Canada at approximately 15 Metres!

Resources:

Facts About Tides  www.surfingsantacruz.com

Wikepedia

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