What Causes the Tides?

Imagine you're holding two balloons tied to a string, one is much bigger than the other. When you pull the string, the smaller balloon moves closer to the bigger one. The same thing happens with Earth and the moon: the moon pulls on Earth’s oceans, making them rise and fall like a giant wave. This is how tides happen every day.

The Moon's Pull

The moon is like a giant magnet that pulls Earth’s water toward it. When the moon is directly above an ocean, the water gets pulled up, causing high tide. On the opposite side of Earth, water also gets pulled away, making another high tide there too. The areas in between get lower tides.

A Daily Dance

As Earth spins around once a day, different parts of the world feel the moon's pull at different times. That’s why we see two high tides and two low tides every 24 hours.

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Examples

  1. A child playing with water in a bucket sees the surface rise and fall when another child pulls on the handle of the bucket.
  2. When you're swimming at the beach and the water gently pulls you up and then away, that's like the ocean being pulled by the Moon.
  3. Imagine a big spoon pulling jelly from one side to the other, that’s how tides work in the ocean.

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Categories: Physics · tides· gravity· moon· oceanography