How does the Moon control Earth's tides? | Stargazing | ABC Science

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[ABCScience]

✨May your day be filled with Space Gandalf levels of wonder. ✨

[samanthahorn]

I watched 5-6 YouTube videos about tides before this one. He explains it in a easy to understand visual way. I learned the most from him.

[kimberlybaldridge]

That was such a clear explanation. The visual aids really help.

[jackiesantangelo]

I can't believe it took me so long to find you - I'm in awe every day. I could follow you, carry your equipment? Kidding, don't worry.

[johngillespie]

I love listening to this guy. Explains things well in easy to understand language, Makes it interesting to learn.

[dananoack]

Homeschool Mom here. Thank you for this reality lesson!

[merrynbrown]

Outstanding! Clearly explained and the example was so practical I can use it in my Science classroom! How wonderful to have an expert that is Australian explaining so clearly! Bravo! Please make more.

[oneeleven]

This ISN’T how the tides are formed at all. It is a common misconception that is all too often put about and it is definitely wrong. The true explanation isn’t hard to follow but it is counter-intuitive. The Moon’s gravity doesn’t pull the tides up into bulges, it is far too weak to do so, and if it did, it would pull equally on everything else too. Also the explanation for the second tidal bulge on the far side of the Earth given here is incorrect.

The Moon’s vertical pull upwards at the surface of the Earth is about ten million times smaller than the Earth’s downward pull, so this part of the Moon’s gravity simply cannot directly lift anything at all. What actually happens is more subtle but makes perfect sense when you get the picture. The Moon’s gravity is only precisely straight up when the Moon is directly overhead. Everywhere else the gravity vector is leaning over a bit in order to point at the Moon. This means that everywhere on Earth away from the Earth-Moon line experiences a small horizontal force in the plane of the surface, pointing towards the Earth-Moon line. Forces like this are called tractive forces and they are a bit smaller than even the small vertical forces, but the key thing is that they accumulate across the huge surface area of the oceans and being horizontal they don’t get overwhelmed by Earth’s gravity which is always at ninety degrees to them. The tractive forces all point towards the place where the Moon is directly overhead, and seawater is fluid and incompressible, so a bulge of ocean a few metres high forms directly under the Moon, and also on the far side of the Earth where the Earth-Moon line comes out. The cause of this second bulge is slightly harder to visualise until you see that everything is symmetrical about the Earth-Moon line. The Moon’s gravity is a bit weaker on the far side of the Earth and, indeed, the second bulge is a little smaller and gives a slightly lower high tide.

All this was worked out by Euler in the eighteenth century, and mathematically modelled by Laplace the Tidal Equations that bear his name. Science has had a good understanding of the Tides for nearly 250 years, but sadly the truth of the matter doesn’t seem to have reached many YouTube producers.

[bethkebede]

I Love your explanation. It’s awesome and I totally get it. Thank you sir! 👍🏽

[g.d.]

Now I know what santa does during his vacation 😇

[mikev]

not sure if you explained the tidal bulge on the opposite side of the moon. I don't think Newton used the word " wobbling" : )

[BlinkinFirefly]

Why is it called "spring" tide? Is it spring as in the season of spring? Or spring like the verb?

[karhukivi]

The critical point here is that the Earth and Moon "wobble" as he puts it, around a point called the "barycentre" that is inside the Earth but not at the centre, it is about 4, 700 km from the centre and moves around with the rotation of the Earth..

[scbabymama]

Fantastic video!!! It makes it even better for my kids when they see Space Gandalf!!!

[materialgurl]

I understand what you're saying but it doesn't make it any less weird. Wow, what a planet!

[adamglltt]

I picked this video to help my 5 year old boy understand a little more about the effect of the moon on the sea. It's interesting and concise

[shotfam_]

If the moon can move the tides in the ocean, it can move us. We are comprised of 75% water in our body.

[wattihrvoltwatwat]

you are not quite correct, the far side is not centrifugal force, its that gravitational attraction is distance dependent and the close water gets attracted more than average so it rises towards the moon and the far side gets less attracted and rises away from the moon

[onixthepirategamer]

You know, I’ve wondered what if the moon had some water on it or a liquid. Like how extreme would the tides there be as the earth has a bigger gravitational pull than the moon has on us. It would be way more dangerous if there was liquid on the moon.

[pwx]

2:12 This is confusing. So if people live in the south in earth, doesn't that mean people will fall into space ? Or what is the explanation. 🧐

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