Reasons for Tides

Mishale

Chief Lister
What Causes Tides?

The Short Answer:

High and low tides are caused by the Moon. The Moon's gravitational pull generates something called the tidal force. The tidal force causes Earth—and its water—to bulge out on the side closest to the Moon and the side farthest from the Moon. These bulges of water are high tides.


A boat in high tide (left) and low tide (right) in the Bay of Fundy in Canada.

High tide (left) and low tide (right) in the Bay of Fundy in Canada. Image credit: Wikimedia Commons, Tttrung. Photo by Samuel Wantman.

High tides and low tides are caused by the Moon. The Moon's gravitational pull generates something called the tidal force. The tidal force causes Earth—and its water—to bulge out on the side closest to the Moon and the side farthest from the Moon. These bulges of water are high tides.

As the Earth rotates, your region of Earth passes through both of these bulges each day. When you're in one of the bulges, you experience a high tide. When you're not in one of the bulges, you experience a low tide. This cycle of two high tides and two low tides occurs most days on most of the coastlines of the world.

This animation shows the tidal force in a view of Earth from the North Pole. As regions of Earth pass through the bulges, they can experiences a high tide.
This animation shows the tidal force in a view of Earth from the North Pole. As regions of Earth pass through the bulges, they can experiences a high tide.



One thing to note, however, is that this is just an explanation of the tidal force—not the actual tides. In real life, the Earth isn't a global ocean, covered in an even layer of water. There are seven continents, and that land gets in the way. The continents prevent the water from perfectly following the Moon's pull. That's why in some places, the difference between high and low tide isn't very big, and in other places, the difference is drastic.


That explains the first high tide each day, but what about the second high tide?
The ocean also bulges out on the side of Earth opposite the Moon.
An illustration of the tidal force causing water to bulge toward the Moon and on the side opposite the Moon. These bulges represent high tides.

The tidal force causes water to bulge toward the Moon and on the side opposite the Moon. These bulges represent high tides.


To get the tidal force—the force that causes the tides—we subtract this average gravitational pull on Earth from the gravitational pull at each location on Earth.
Tidal force = Moon's gravitational pull in a specific location on Earth — Moon's average gravitational pull over the whole Earth

The result of the tidal force is a stretching and squashing of Earth. This is what causes the two tidal bulges.
rrows represent the tidal force. It's what's left over after removing the Moon's average gravitational pull on the whole planet  from the Moon's  specific gravitational pull at each location on Earth..

Arrows represent the tidal force. It's what's left over after removing the Moon's average gravitational pull on the whole planet from the Moon's specific gravitational pull at each location on Earth.
These two bulges explain why in one day there are two high tides and two low tides, as the Earth's surface rotates through each of the bulges once a day.


 

The.Black.Templar

Chief Lister
Staff member
All of you up there have failed as "scientists", because you have broken the cardinal sin of assuming a question is irrelevant.

The centrifugal force on your body at the equator is 0.034 m/s2 times the mass of your body. The centrifugal force at the poles is zero.

Your total weight at sea level at the equator (gravity minus centrifugal force) is therefore 9.764 m/s2 times your mass, whereas your weight is 9.863 m/s2 times your mass at the poles. If we use a more accurate model (such as taking into account the shape of the continents) these numbers will be slightly different, but the overall point will be the same: you weigh about 1% less at the equator than at the poles. If you weigh 200 pounds (90.7 kg) at the North Pole, you will weigh 198 pounds (89.8 kg) at the equator.

If you factor in the moon tides your total weight also fluctuates.
 

mzeiya

Chief Lister
i was also amazed.
there must be many theories/explanations... that we were taught along time ago that have been refined but we aren't aware of.

seems one doesn't stop learning until they die.
True that but this was taught in Geography form 3..ama wengi wenu mlidrop hiyo subject ya usito :D
 

Mishale

Chief Lister
True that but this was taught in Geography form 3..ama wengi wenu mlidrop hiyo subject ya usito :D
wewe labda ulkua na walimu digital. ama ukua unatumia textbooks new edition
was taught that it's the moon that pulls and releases the water only. not that we rotate around the pulled water.
 
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