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Why do tides happen twice daily?

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Answer: Moon creates two tidal bulges

Earth rotates twice per dayWrong. Earth rotates once per day (24 hours), not twice. Two daily tides occur because the Moon creates two tidal bulges on opposite sides of Earth.

Moon creates two tidal bulgesCorrect! The Moon's gravity pulls ocean water toward it (creating a bulge on the near side). On Earth's far side, inertia creates a second bulge as the Moon pulls Earth itself more than the distant water. As Earth rotates through both bulges, most coasts experience two high tides ~12.5 hours apart daily!

Ocean water sloshes backWrong. Water does move, but tides aren't random sloshing—they're predictable responses to the Moon's gravity creating two simultaneous bulges.

Go deeper: Tidal force · Tidal bulge
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