The tide doesn't rise and fall!

[LittleSister]

A different way of looking at tides:

 

[Sandy]

Everything is relative.

 

[dombuckley]

Good, but ignores the fact that the earth also bulges (to a lesser extent) under the influence of moon and sun (called 'earth tides').

 

[sarabande]

And the earth is permanently flattened at the poles, being about 15 miles wider diameter at the equator. It's an blate spheroid.

I don't buy the video's explanation of the earth rotating inside the outer coating of water. The speed of earth's rotation at the equator is1660 km/h, which would make for interesting tidal streams and a LOT of erosion if the outer water envelope stood still.

Ocean tides are a lot more interesting than that. Arctic Pilot is your man with the explanations about intertidal, semi-diurnal, and storm surges.

 

[Porthandbuoy]

Ocean tides are a lot more interesting than that. Arctic Pilot is your man with the explanations about intertidal, semi-diurnal, and storm surges.

As well as degenerate amphidromes.

 

[RunAgroundHard]

The tide does flow in and out. The deformation in the water level due to tidal forces exists of course, but the surface is not homogeneous and forces the water to flow around and through restrictions. There is also a delay in the height of tide in relation to the tidal force, hence the water flows to the strongest tidal force.

The can be seen in many places around the world, as well as obvious differences in sea water level over small areas. External forces such as air pressure and gales can delay the movement of water due to tide force.

Also each molecule of water that has to bulge due to tidal force must move to that position, hence it flows.

 

[Slowboat35]

Talk about stuck with language - the man's hoist on his own petard, apart from talking utter bullshine.
If the earth rotated within the 'bulge' as described and illustrated then currents would flow at around 1000mph at the equator...

 

[mjcoon]

And the earth is permanently flattened at the poles, being about 15 miles wider diameter at the equator. It's an blate spheroid.

Since you put "an", you evidently meant to put "oblate"...

 

[Laysula]

And the Sun doesn't go up and down.

 

[Mister E]

Has he been listening to viago?

 

[srm]

He might be correct, on a planet where the moon, planet, and sun remain fixed in the same relative positions and a uniform depth to the ocean with no land masses. Our earth sun and moon have a much more dynamic relationship making for a much more interesting marine environment.

 

[mjcoon]

He might be correct, on a planet where the moon, planet, and sun remain fixed in the same relative positions and a uniform depth to the ocean with no land masses. Our earth sun and moon have a much more dynamic relationship making for a much more interesting marine environment.

I don't intend to watch the video (life's too short, at 80 anyway). But if there are any changes in depth the water cannot mysteriously levitate so the length of the water column, and hence its (incompressible) volume, must change. So there has to be lateral flow, to or from adjacent water columns, to accommodate that...

 

[LittleSister]

. . .

I don't buy the video's explanation of the earth rotating inside the outer coating of water. The speed of earth's rotation at the equator is1660 km/h, which would make for interesting tidal streams and a LOT of erosion if the outer water envelope stood still.

. . .

Talk about stuck with language - the man's hoist on his own petard, apart from talking utter bullshine.
If the earth rotated within the 'bulge' as described and illustrated then currents would flow at around 1000mph at the equator...

He doesn't say the water is stationary, he says the bulges in the water are stationary.

. . . Ocean tides are a lot more interesting than that. . . .

They are indeed, and I am sure that he would agree.

(He is famous as someone who delights in the myriad 'interesting' things about the world and universe, and an expert at making science (and astronomy in particular) interesting and accessible to the public.)

He is by no means denying all the interesting and complicating factors in tides, just adding further interest and fresh perspective on its fundamentals.

He might be correct, on a planet where the moon, planet, and sun remain fixed in the same relative positions and a uniform depth to the ocean with no land masses. Our earth sun and moon have a much more dynamic relationship making for a much more interesting marine environment.

I am sure that internationally famous astrophysicist and science educator would be pleased to be put right by you!

Neil deGrasse Tyson - Wikipedia

 

[LittleSister]

I don't intend to watch the video (life's too short, at 80 anyway).

The video is just 51 seconds long. I hope you find something useful to do with the time you've saved!

 

[mjcoon]

The video is just 51 seconds long. I hope you find something useful to do with the time you've saved!

To provoke that much discussion I thought it must be hours!

 

[oldmanofthehills]

I don't intend to watch the video (life's too short, at 80 anyway). But if there are any changes in depth the water cannot mysteriously levitate so the length of the water column, and hence its (incompressible) volume, must change. So there has to be lateral flow, to or from adjacent water columns, to accommodate that...

Of course, but he is not suggesting there isnt, though his explanation is a bit overly dramatically simplified on that point. He is merely pointing out that the bulge keeps trying to align with the moon, and also the sun as its their gravitational influence that raises the bulge thus the bulge is stationary relative to the moon. Indeed we must be fractional lighter if the moon is overhead - just think of us as sentient water, or at least semi sentient.

Of course the whole caboodle is whizzing through space and rotating with the galaxy, so there may be semantics in the term stationary

 

[Thistle]

The video is just 51 seconds long. I hope you find something useful to do with the time you've saved!

Yes, I poured another G & T.

 

[Rappey]

I can't see how any of it is possible as the earth is flat ?

 

[srm]

I am sure that internationally famous astrophysicist and science educator would be pleased to be put right by you!

But obviously not an oceanographer, hydrograhic surveyor or marine navigator.
He is using the simple tidal theory for a water world, where bulges would remain stationary.
On our world the tidal waves rotate around amphidromic points, or tidal nodes, with zero range. There are three in the North Sea. Ocean basins have one or more, influenced by surrounding land masses and depths.
Simplified world map:
Amphidromic point - Wikipedia
Or if you want more text info this is a starting point for a potentially complicated subject:
Amphidromic point - Wikipedia

 

[LittleSister]

But obviously not an oceanographer, hydrograhic surveyor or marine navigator.
He is using the simple tidal theory for a water world, where bulges would remain stationary.
On our world the tidal waves rotate around amphidromic points, or tidal nodes, with zero range. There are three in the North Sea. Ocean basins have one or more, influenced by surrounding land masses and depths.
Simplified world map:
Amphidromic point - Wikipedia
Or if you want more text info this is a starting point for a potentially complicated subject:
Amphidromic point - Wikipedia

But he's not talking about the fine detail such as tidal waves in the North Sea, but the overall vertical movement which generates, and provides a context for, such local phenomena.

The two - bulges at earth scale and local scale amphidromic points - are not incompatible, they are interrelated.