Tides: the Moon in Motion

Today in class I learnt the role the moon plays in regards to our ocean's tides... Tune in for more information.

Ocean tides are caused by the Moon's gravitational pull. The Earth's oceans responds to the moon by bulging and dipping as the moon revolves around the Earth.

Does the Sun not have an effect on Earth's tides too?

Well... both the sun and the moon actually exert tidal forces. The moon exerts a much stronger force despite the size comparison.

This is because tidal forces are dependent on distance rather than mass. The moon is 384,400km away while the sun is 149.6 million km away.

What about High and Low tides?

The oceans on the earth that are on the same side of the moon always want to bulge out towards the moon. When this happens, it is what we call a high tide. This also happens on the side farthest away from the moon. If you are not on one of these bulges, you will experience

a low tide. The earth rotates through two tidal "bulges" every lunar day. Costal areas experience two high tides and two low tides every 24 hours and 50 minutes. It takes 6 hours and 12.5 minutes to go from low to high or high to low. And High tides occur every 12 hours and 25 minutes apart.

Why do the oceans bulge to form High tides on the side farthest from the moon?

The bulge on the far side of the earth is actually caused by inertia. The gravitational force of the moon is less because it is farther away. The inertia exceeds the gravitational force, and the water tries to keep going in a straight line, moving away from the Earth, also forming a bulge. This bulge is sometimes referred to as a "low high tide".

Are there different types of high and low tides?

Spring Tide:

Occur twice a month when the full and new moons occur. The Earth, Sun and Moon are nearly in alignment, resulting in slightly larger average tidal ranges. This causes higher High tides and lower Low tides.

Neap Tide:

Also occurs twice a month 7 days after a spring tide. The Sun and Moon are right angles to each other. The bulge of the ocean caused by the sun, partially cancels out the bulge of the ocean caused by the moon. This results in lower High tides and higher Low tides.

I hope you enjoyed reading this!