The Mystery of Earth's Tides

No doubt you've sat by the ocean's edge and wondered why the tides move in and out. Come on in and see why. The water's fine.

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• ignite
• learning
• ignitelearning
• science
• astronomy
• oceanography
• tides
• tidal
• sun
• moon
• water
• earth
• gravity
• orbit
• celestial

[kingkobra813]

two balls and bulge.... got it thanks!!!

[i7887]

I know this comment is over a year old but i cant resist. Please don't recommend this video to your son as the explaination for the bulge on the opposite side of the Earth is incorrect. It has nothing to do with the rotation of the Earth, only gravitational forces caused by the Moon and to a lesser extent, the Sun. The overly simplified reason is that gravity is affected by distance. So the Moon pulls the Earth away from the ocean on the far side of the Earth "leaving the ocean behind".

[thecoolrayan08]

lol

[thecoolrayan08]

is that guy a peice of poop?

[SuperCartoonAddict]

Ok, Im going INSANE looking for the song (from this video, I saw it in 8th grade science) it was like "It's just the phases of the moon", I wanna send it to all my friends from that class!! Can ANYONE link it to me PLEASE???

[viditibi]

and why not the moon also pulls the ocean towards it on the far side? i mean, you say moon pulls earth away from the ocean on the far side of earth "leaving the ocean behind", but how leaving the ocean behind?? why don't moon pulls also than ocean behind? gravity affects all materia being near or far

[i7887]

@timmydoulos None of it supports that theory, its simply stating it then later explaining why its wrong. There is no way to prove it to you in youtube comments so go ahead and keep on believe. You need to have a greater understanding of physics first.

I don't know what to say about your link other than that im disappointed in nova

[timmydoulos]

@i7887 ...a straight line is greater on the opposite side of the earth from the moon because it's radius from the center of rotation is greater. (This orbit is separate from the rotation of the earth about it's own axis... this would give an equal force to all points on the Earths surface, as the radius is effectively equal) Do visit pbs.org/wgbh/nova/earth/what-c­auses-the-tides.html and check out their explanation.

[timmydoulos]

@i7887 Thanks for your link to lhup.edu/~dsimanek/scenario/ti­des.htm . I had already been to your site. Some of your supporting links actually undermine the premise that you are making?

At least one SUPPORTED the idea of a common center of mass between the Earth and the Moon (barycentre) by which the Earth and Moon rotate each other.

The center of mass between the Earth and the Moon, by which they orbit one another, means that the tendency for an object to continue in ...

[i7887]

@timmydoulos Like I said, its an oversimplification. Add up the vectors caused by gravity and you will see that its gravity alone. I have a degree in physics and astronomy and I can guarantee that I know what Im talking about.

Read this is you don't believe me, its written at about a high school level so its easy reading. Its made to show how most lower level textbook are just plain wrong when it comes to the physics of tides

ht tp : // ww w . lhup . edu ~ dsimanek / scenario / tides . ht m

[timmydoulos]

A better explaination of this duel rotation theory is found at pbs.org/wgbh/nova/earth/what-c­auses-the-tides.html

[timmydoulos]

@i7887 Are you claiming that "the Moon pulls the Earth" - a massive, relatively rigid body - "away from the ocean" - a fluid, highly movable substance.

Wouldn't you think that the water would move around the earth toward the gravitational pull of the moon if your theory was correct? There is no way the Earth would be "leaving the ocean behind" as the ocean is attracted to the Earth, by it's gravitational pull.