It feels silly to ask, but a 'like' (thumbs up) to this video would be appreciated. Of course, only if you do believe it is good. The KZread system simply works that way. It isn't geared towards spreading truth; it's geared towards spreading advertising space. That's why popular videos do better. I am trying to spread this explanation of the tides - against the prevailing current of the abundantly presented popular but incorrect explanation. Your 'likes' can help spread the message.

Hello Tribus Montibus Oceanography! You asked me to comment on your work and I am very happy to do so. The graphics and images are great; you have clearly put a lot of thought and effort in to them, and to me they work really well. I am particularly pleased that you are correcting the many incorrect ‘explanations’ of the tides that can be found on the internet. Euler and Laplace worked it all out in the eighteenth century and gave us a very effective model capable of accurate predictions, but sadly, too many people are still promoting the old, disproven, and frankly impossible explanation. I would be inclined to simplify this part even more and drop the ‘differential gravitational attraction’ which might sound a bit off putting. The key to understanding the situation is to realise that the Earth’s gravity swamps all other gravitational forces at the Earth’s surface, but only in the local vertical plane. As you say here, it is about ten million times stronger than the Moon’s influence so the lunar field simply cannot lift anything against such a stronger field. However, the Earth’s gravity is always vertically downwards which means that any horizontal forces are not overwhelmed but can accumulate. The Moon’s gravitational pull is only purely vertical when the Moon is overhead. Everywhere else on the Earth’s surface, the Moon’s pull has to ‘lean over’ a bit in order to point at the Moon. This produces horizontal gravitational components which are the cause of the tides. Although these tractive forces are very small compared with the Earth’s downward pull, they are always at ninety degrees to it so aren’t overwhelmed, and the oceans cover a vast surface area of the planet and seawater is incompressible. This is a bit like pushing on opposite sides of a rug and producing a bump in the middle, or similar to how mountain ranges are formed by colliding plates. In the case of the tides, the bumps are only of a few metres in magnitude at their highest which shows both how small the tractive forces are and how relatively dense seawater is. Another key point to realise is that the tractive forces are convergent towards the the sublunar and antipodal points. Convergent forces in an incompressible fluid will exploit any remaining degrees of freedom, in this case forming a bulge in the vertical plane. Also of note is that the tractive forces arise because the Earth presents an extended target to the Moon’s gravity. In other words the Earth is big and the Moon is nearby. Explanations which reduce the bodies to their centres of gravity cannot succeed because of this. P.S. I was lucky enough to fly the BAC One Eleven for Dan Air at the start of my career. It was designed to be a means of transporting large amounts of noise over short distances, and fulfilled the role admirably.

@TribusMontibus

2 жыл бұрын

Hello One Eleven, Thank you for taking the time to look at and comment on my videos. It is clear to me that your understanding of the tides goes a good deal further than what one usually encounters. I take your point about about ‘differential gravitational attraction’. In fact, I wasn’t too happy to start the series with this concept, but I felt I had to. I chose the thumbnail specifically to be less-than-appealing, because I actually hope that people will be drawn to episode 2 (which is currently in the making) first. Episode 2 will be ‘juicier’ than episode 1, and I don’t want to risk viewers ‘tuning out’, because of boring content. What I hope to do is to ‘hook’ them, when episode 2 demonstrates why the moon’s gr avitational attractions at sublunar and and lateral cannot contribute significantly. For many people this is surprising, because, as you say, it is counter-intuitive. Having established that, I hope the really curious ones will loop back to episode 1, which attempts to show that the tides are not about absolute forces. For that reason, the episode 1 thumbnail doesn’t jump out with appealing colors and has its real title almost hidden in the waves. I hope to finish episode 2 in a month or so, work and family life permitting. I’m stillworking on the best way to express one or two things in a clear yet appealing manner. Besides, I hope to convey a point which wasn’t lost on you; that the tides are very much a 3-dimensional phenomenon. I feel that many explanations put so much emphasis on 2D-diagrams that the 3D implications (like the convergence) are often overlooked. When I do finish it, I hope you’ll take a critical look at it again. It feels silly to ask, but any ‘thumbs up’ and subscription would be greatly appreciated, as it helps me to ‘spread the message’. Kind regards, Garret

Very good explanation and channel in general. Looking forward to your next one.

@TribusMontibus

2 жыл бұрын

Hello R, Thank you for your kind comment. This is the kind of input that motivates me to keep going. I must ask for your patience however. The video which is on the cutting table right now is on a slightly different subject; why is a frigate a frigate? (if you think I have a lot to say about the tides, don’t get me started on naval matters). One parallel to the tides; it is also a matter on which many will offer you an explanation which sounds plausible at first glance, but is hardly ever correct. This also serves the purpose of giving me a bit more time to consider exactly how I will shape the next tides video. It is very clear to me which mechanism I have to explain in the video, but it isn’t desirable to present a dry summary of formulae. There are a few thing which I still have to express in a satisfactory manner. The challenge - which fascinates me - is to find the best way of expressing how it works, without compromising physics, through over-simplification. When I listen to a lot of explanations I find that many explainers are unaware that they have come to accept such simplifications as the full explanation and never venture beyond them to verify them through observations and/or calculations. As many of them are well-thinking people, they would soon find out that they are wrong (or at least, incompletely informed). This is what I hope to achieve with my channel; to offer a well-founded explanation to those who suspect that something is ‘off’. I realize that this will never ‘make it big’, and a majority of viewers will happily flock to the incorrect explanation, because that doesn’t question their ‘certainties’ too much. But I consider every single person who finds that these videos ‘answer a question they hadn’t yet asked’ a small victory. Thank you, and I hope my next video doesn’t disappoint.

@r-gart

2 жыл бұрын

@@TribusMontibus you might be wrong to think that there isn't a demographic of users that are rooting for more in-deep knowledge about such topics. We are surely out there. There are far too many shallow videos in KZread; on the other hand videos like yours that try to trim all the loose ends in a subject that is highly misleading, like tides, are a rare gem. On the content side I think you're on the spot, but if you plan to continue the content creation my suggestion would be, if you allow me, to just work a little bit more on your titles and thumbnails. Just get them more interesting to click on. Maybe roll some "Why (big youtuber) got it wrong with X". Things like that. I know it might feel sometimes that you're playing the trick-the-audience game but no one wants to work for free and I think your content deserves way more views that it currently has. Just the global tides animation (like a heat map) that you brought to the table made my mind blown and I would never have seen that if it weren't for your comment on another video telling us about your KZread channel. Having that said, I wish the best of luck to you, and thanks so far for your creations.

@TribusMontibus

2 жыл бұрын

Hello R, Thank you for your reply. I see your point. This may sound a bit strange, but I made the thumbnail for this video less-than-appealing on purpose. The reason is that I felt I had to start this new series with such a dry subject, for the sake of completeness. It is on purpose that the title is almost invisible in the waves. I think that this video will be the hardest-to-digest in the series. Number two is projected to be a lot juicier (in a month or two we’ll know) and I actually hope that people will enter the series at number two (then loop back to number one, only after they realize they’re ‘on to something’ and want to know more). Number two is where the big surprises start for those who have seen a few vector constructions already. But it will demonstrate once-and-for-all how the tides are NOT formed by the forces working on the oceans at the point closest to the moon. From experience; this surprises most people. But ‘the big kicker’ is kept in reserve for an even later episode. You’ve already noticed the ‘heat map animation’. It isn’t my work. Dr Erofeeva and Dr Egbert from Oregon State University are kind enough to let me use it. Although Dr Erofeeva was a bit surprised that I preferred this old simulation over her newer one, which is much more detailed. But this one fit my purpose better because it is clearer on the big picture. That will be the video in which I get rid of the misconception that tides have anything to do with the moon being overhead (for 90% of the world’s beaches they do not). I may eventually aim an arrow or two at other KZreadrs. A great eyesore to me is the piss-poor, but very popular video by the Australian KZreadr ‘Atomic School’. This is the video which is presented to school children when they google ‘how tides work’. I have tried to reason with the man but he’s not ‘the reasonable type’ and, unfortunately, none too smart. He is so inlove with the success of the video that he has blinded himself to anything which endangers its perceived status. My initial intention was to get him/help him to produce a correct tides video, because he already has an audience. But nothing came of this, except for a very tiresome discussion with a willfully ignorant, easily offended man. I understand that such approaches work better on KZread. It’s not difficult at all to aim an arrow at Neil deGrasse Tyson (he understands the astrophysics very well, but not the response of the oceans) but I like him. I’m afraid that this would draw more interest, but that many of those viewers would just come over to express their annoyance that I have dared to question their hero. So, for now, I plan to quietly plod along with the series, hoping to hang on to viewers like you, who approach open mindedly. Kind regards

Very good explanation. 😊 could you make a video talking about rossby waves?

@TribusMontibus

2 жыл бұрын

Thank you Jhony. To be honest, Rossby waves are not ‘my specialty’. They are interesting in their own right but have negligible influence on the ocean tides. In that respect, they are of more interest to meteorologists and oceanographers who are primarily concerned with global currents. To be even more honest, I’d have to read up on them myself and I’m therefore not sure if I’d be the right person to tell you anything useful about them. Kind regards

Hi Garret, Max here again as invited. Nice video with quantitative comparisons. I will refrain from being too critical and I have not checked all the numbers you mentioned there (so unable to agree or disagree). Only some quick and general thoughts (except one specific - the last one). 1. I agree there are plenty of people out there touting misleading information or unplausible explanations - I guess probably because these people themselves indeed don't understand the subject. But I do think in the simplest terms, it's correct to say the tides are largely caused by the pull of the Moon. If going into the detail, indeed the tidal-generating forces are a field (just like the gravitational field or other spatial fields), and quite often it can be said as the difference, residual, differential, or the vector sum of the Moon's pull and another centrifugal 'force' (and the most important or apparent components). But still, the Moon's pull is always one important contributor. I think it goes too far to say this simplistic explanation of the Moon's pull is totally wrong. 2. It' probably a personal preference, but I always find it strange to explain a force in terms of acceleration when the object is actually not being accelerated by that force (like in the example of an object under a gravitational force by the Earth but sitting there still on the top of a scale). This is not a big problem though. 3. I would never disagree with the point that the Sun is also a contributor to the tides. But since, first, its contribution is of smaller amplitude (I believe), and most importantly, its period is much longer than one or half a day, so it makes it much easier and is much simpler to leave it out of the equation when we are to explain only the diurnal or semi-diurnal tides (which are the main components). After some very fresh study myself, the explanation of tides if only in the Earth-Moon system now appears quite simple and straightforward to me. 4. I believe you got it wrong at 1:44 by saying the centripetal acceleration of the Earth, orbiting along a circle of a greater radius, is less than that of the guardsman (less radius). It's the opposite. Given they are both revolving at the same angular velocity, the greater the radius, the greater is the centripetal acceleration (because with a constant angular velocity, the centripetal acceleration is proportional to the radius of revolution). [Note: there is a big caveat or discussion point here which can trip many people up - probably including myself. But I will leave it here for now. Without dealing with this caveat, at least it's incorrect - I believe - to say the centripetal acceleration at the centre of the Earth is less than that at the point of the guardsman.] Cheers, Max

@TribusMontibus

2 жыл бұрын

Hello Max, Thanks for your reply. I can answer your points. 1. I agree that most explainers do not understand the tides themselves. Typically they are totally unaware of that. But I strongly believe that it is necessary to call it 'totally wrong'. The reason is that, if you leave people to believe that the 'vertical pull' (which is at the core of pretty much all of those explanations) contributes to the tidal rise in any significant way, you will never get them to consider the mechanism which actually does cause the water to rise. I don't actually mind when people say that tides are caused by 'the gravitational tug of the moon on the ocean water', because that's true (even though in most people it will conjure up mistaken ideas). But I object to ANY mention that 'the moon is PULLING the water UPWARDS', as this is factually incorrect and reinforces the emphasis on the wrong mechanism. 2. You are right; it is a matter of preference. And, as you see me do quite a few times; later in the process I have to make it clear that these accelerations most often don't actually happen. Hence the use of the word "want". But the reason that the use of accelerations is common in astrophysics is because it is the same for a given position in a system. This makes it less complicated to compare the movements of very different masses without having to consider greatly varying forces. 3. Indeed, most astrophysicists totally agree with you and consider only one external gravitational influence when analyzing tidal forces. The internet runs rife with people who are confusing themselves when considering multiple sources and develop all kinds of strange reasoning as a result. Whereas it is much easier to regard them individually and just add up the resulting constituents with their appropriate periods. 4. I'm afraid you have fallen into your own 'trap', of labelling forces, here. Although I have to admit that my labelling contributed to it. I think you are confusing cause and effect. What you are saying about Fc holds true for point masses in a stable orbit or for objects on a rotating disc with constant angular velocity. In those cases it is a useful tool to determine what the Fc must be for the mass under consideration. This is how you can derive the Fc (I prefer ac) for the earth as a whole in its orbit. But this does not hold true for an object on the 'near side' to an attracting mass. According to the gravitational force formula it experiences a greater acceleration (a good example of why it is more productive to consider accelerations rather than forces). It certainly doesn't comply with 'lesser radius, lesser acceleration'. The only criticism I'd tend to agree with, concerning my use of words in the video, would be that I might have said: 'the guardsman wants to accelerate more towards the source of gravitational attraction (but can't) than the centripetal acceleration of the planet'. But, this discrepancy in accelerations is exactly the source of tidal forces. Do you see what I mean? Sometimes when you are too concerned with 'labels' this can get in the way of seeing what's actually happening. Kind regards, Garret

@maxwang2537

2 жыл бұрын

@@TribusMontibus All good with 1-3, though your 'preference' over acceleration is causing problems, at least to me, here again on 4, which let me address - I checked again your video, I don't think I'm mistaken. You said, "So it [Earth at its centre] will experience a slightly lesser centripetal acceleration than the guardsman". You are talking about the CENTRIPETAL acceleration (or force) here. But in your response, you are now mixing (I've tried to use "confusing") it with the acceleration, or force, due to the gravitational attraction (of either the Earth or the Sun). In discussing this centripetal force, you are now saying "[But this does not hold true for an object on the 'near side' to an attracting mass.] According to the gravitational force formula it experiences a greater acceleration". I don't understand why these two need to be mixed when they can be isolated and dealt with separately without causing any confusion. I'm unable to continue the debate (this is not saying you are necessarily wrong, though I do believe) because your way of analysing mechanical problems (not complex ones actually only static or can be treated as static) is too different from what I'm used to and beyond my comprehension. So please never mind all of the above. The only one point I'd like to test if we can still have some common grounds is on some selected statement of the NOAA - Our Restless Tides article (Chapter 3) - Do you agree or not? Thank you. (Text in square brackets added by myself as what I believe is supported by this NOAA article). [1] "Note that the earth revolves around G, but does not rotate around G." and [2] "And, since the centre-of-mass of the earth is always on the opposite side of this common centre of revolution from the position of the moon, the centrifugal force produced at any point in or on the earth will always be directed away from the moon [and constant, including for the part of the Earth that is at the Moon side relative to the barycentre of the Earth-Moon system]."

@TribusMontibus

2 жыл бұрын

@@maxwang2537 Hello Max, Sure, we'll let it rest. But I will try to urge you to do the following when thinking about it. Don't get bogged down in labels. The important thing to realize is that the near side attraction is greater and would want to make a mass there describe a tighter orbit than it does. But, on the NOAA text; no problem. But please include an indication where in the article you have found these quotes. Otherwise I have no idea what I am commenting to. By the way, if you've noticed, this article agrees with the incorrectness of the 'pulling upwards' (Chapter 3, half way down the page, point 4. 'The Tractive Force'): "The tide raising force of the moon, is, therefore, entirely insufficient to "lift" the waters of the earth physically against this far greater pull of earth's gravity". But yes, it seems to me that I do agree on both quotes from the NOAA text. Kind regards, Garret

@maxwang2537

2 жыл бұрын

@@TribusMontibus Thanks for your reply. I would have included a link to the reference I mentioned (the one you previously pointed to me in your next video of this series) if I had been able to (I was not allowed by YT to include links according to my experience - for multiple times). But I did indicate where I meant "NOAA - Our Restless Tides article (*Chapter 3*)" - and this entire chapter is one webpage where one can easily pinpoint the statements I quoted by copy and search. (This is the silly restriction on YT comments not accepting a link, not to mention a picture.) Good to know you don't have a disagreement with these statements of NOAA. I don't quite understand where I boggled down in labels (I only recall I used *a* for twice or so, for accelerations, which possibly caused confusion. Sorry if that's the case) and if I indeed did boggle down in labels, what adverse effect that has made in the discussion or in my reasoning. Also, I'm again confused by your saying "The important thing to realize is that the near side *attraction* is greater ..." when I think we were talking about centrifugal force or centripetal acceleration (the same thing) but "attraction" here I believe you mean the gravitational attraction, which is a completely different thing. Thank you anyway for the discussion. All the best with your series.

@TribusMontibus

2 жыл бұрын

@@maxwang2537 Hello Max, it is a pity that discussions through e-mail are so limited in their scope. It is always better to sit down over a cup of tea and see each other's immediate reaction. You cannot separate the forces from the accelerations. I could also have said: 'the important thing to realize is that the acceleration, which the attractive force wants to cause, is greater on the near side'. It's pretty much the same thing. The reason I said that I thought you got bogged down on labels is because you started focusing on the book definition of Fc (or ac) and therefore thought I had made a mistake in the video. I think it a pity, because it diverted attention from the really important point; that the gravitational influence on the acceleration/path/resultant force (really doesn't matter which one of these words you pick) is greater. But sometimes discussions don't work because people are on different wavelengths. No hard feelings, and best of luck on your search. It is a fascinating subject. Kind regards, Garret

The explanation was good but that brings me to another question. If what's explained is indeed true, how come the only noticeable effect of the gravitational pulls differential are on oceans? I still don't get how great lakes are not affected by this. Lastly if these forces are capable of affecting water molecules in such a significant manner then it stands to reason that they would affect the atmosphere in an even greater manner, yet I have not heard of the atmosphere bulging due to such forces...

@TribusMontibus

2 жыл бұрын

Hello Again, I see you haven't watched the OTMS-2 video yet; it answers a lot of your questions. The great lakes ARE affected by it. But first you need to understand how it builds up, and that has nothing to do with 'pulling upwards'. The atmosphere IS affected by it, but tidal forces on air are overcome by other atmospheric pressure gradients, by such a degree that you'll be hard pressed to notice them. The great tidal bulges in the oceans are a fallacy; they don't exist. The tidal forces cause partial rises in the southern oceans, which affect the connected oceans. Please just watch the video: Tides - How the moon raises ocean water It is designed to answer your questions. Kind regards, Garret

@TribusMontibus

2 жыл бұрын

By the way, there is a word-document on our website you will probably find interesting. If you google: ocean tides - how to embarrass your science teacher google should show our website www.tribusmontibusoceanography.com in the search results and you can click to the document with the embarrassed looking teacher. I am a bit busy this weekend, helping my daughter set up some science tests for school and preparing for a flight test on Monday. Kind regards, Garret