01
Near side: pulled harder
Ocean water on the side facing the Moon is pulled more strongly than Earth's center, stretching a bulge toward the Moon.
Moon · Question
Why are there two high tides a day, not one?
If tides were just the Moon "pulling" water toward it, there would be one high tide a day, on the side facing the Moon. There are actually two — because tides come from stretching, not simple pulling.
Visual model
Spring tides vs. neap tides.
Sun and Moon pull along the same line, reinforcing the stretch on both sides of Earth — the highest high tides and lowest low tides of the month.
Sun and Moon pull at right angles to each other, partially canceling out — the smallest difference between high and low tide in the month.
What's simplified
Why two bulges, not one?
02
Far side: left behind
Water on the far side is pulled less than Earth's center is, so it's effectively "left behind" — stretching a second bulge away from the Moon.
03
Earth rotates through both
As Earth spins once a day, most coastlines pass through both bulges — that's why most places get roughly two high tides every 24 hours.
Misconception check
Quick check.
Quick check
Go deeper
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Next in this series →
Earth's seasons ↗
Why tilt creates seasons, not distance.
Moon
Moon phases
Spring tides happen at new moon and full moon — see why.
Moon
Tidal locking
The Moon's own rotation was shaped by this same tidal force.