Alt text: They’re up there with coral islands, lightning, and caterpillars turning into butterflies.

  • TheReturnOfPEB@reddthat.com
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    9 hours ago

    At some point I saw a yt science video saying that the water isn’t moving but the dirt bit is the bit moving during tides

    and i don’t understand why the tides on the Right Hand coast are like clockwork and the Left Hand side of the country the tides are like “what time is it IDGF HIGHTIDE”

    found it “rotating through the tides”

    • psud@aussie.zone
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      3 hours ago

      What he’s saying is there is always a bulge of water pointing at the moon (and another pointing away from it) the earth spins so the land sees the bulge coming and retreating as our bit of coast passes under the moon

      It’s a bad description because the water also spins with the rest of the world, so though there always is a bulge that is stationary relative to the moon, there is always different water being part of it.

    • LOGIC💣@lemmy.world
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      9 hours ago

      I’m not sure what that video said, exactly, but both water and dirt move because they are both affected by tidal forces.

      Tide is caused when an object, like Earth, is large enough to experience a difference in the effects of orbital gravity from one end to the other. The center of gravity of an object does not experience tidal forces.

      Since most of the Earth’s surface is water, and the water is on top of the dirt, the water should be affected more by tidal forces than the dirt underneath it.

      The video may have been talking about how the dirt affected by tidal forces also pushes the water, causing a compounding effect or something.

      • BCsven@lemmy.ca
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        3 hours ago

        In the video he’s saying the line between center of moon and center of earth has the most tidal force on the water, while the earht spins through that zone. It was not saying that the water stays 100% stationary and land spins through it, just that the height of water will always be high at that line as the earth rotates

    • marcos@lemmy.world
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      9 hours ago

      Some of the first mechanical calculators were created to predict tides (~3 centuries ago), because they are a really complex thing that the popular explanations completely paper over and pretend it’s simply the water keeping pace with the Moon.

      • MotoAsh@piefed.social
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        8 hours ago

        It’s shown like that because the water is trying to do that, to anthropomorphise it. Though of course that’s not what the water does everywhere because fluid dynamics get pretty nuts when there’s a ton of land in the way.

        • psud@aussie.zone
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          3 hours ago

          Also part of the tide is solar, if you see a highest high tide or lowest low tide, it is very likely it will be at a full or new moon as that is when the moon and sun are aligned, with the moon on one side or the other of Earth (or lagging that by days due to land getting in the way)

        • MotoAsh@piefed.social
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          3 hours ago

          To expand on the idea, even weather effects the level of the tides rather significantly… For a clear example, look at hurricanes. They can approach double digits in feet of storm swell if they’re severe enough.