Tides intro!

The reversing of St. John River is caused by ocean tides.

This is the Bay of Fundy the river is part of that system.

What are Tides?

The rise & fall of ocean water that occurs every 12.5 hours or so. The water rises for 6 hours and then falls for 6 hours.

Tide

The force of gravity pulls the moon & Earth (including the water on Earth's surface) toward each other!

Gravity

mainly by differences in how much gravity from the moon and the sun pulls on different parts of Earth.

​​Tides are caused...

This also means there are 2 places with low tides!

There are 2 places with high tides!

1 high tide occurs on the side of the Earth that faces the moon. A 2nd high tide occurs on the opposite side of Earth. (Look where the low tides are!)

As Earth rotates...

Changes in the position of the Earth, the moon, and the sun affect the heights of the tides during a month.

Spring tides occur. These are tides with the biggest difference between high and low tides.

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During a new or full moon...

Neap tides occur. These are tides with the least difference between high & low tides.

During a 1st quarter or 3rd Quarter moon...