# How should I be thinking about tides?

I am working on a project for physics that involves tides. This is my current mind set when thinking about tides:

The earth applies a gravitational force on some mass M. The moon & sun apply a gravitational forces on the mass M away from the earth. The bodies of water on the earth have some acceleration towards the moon & sun due to their forces (F=ma). The bodies of water accelerate till they reach a sort of equilibrium between forces.

I would like you to poke holes in my understanding of tides and try and answer my naive questions bellow.

How would you describe tides effected by the moon using forces? How can that be used to calculate the height of tides?

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Don't ask Bill O'Reilly. He was completely stumped by tides, and attributed them to an act of God. Lol! –  ja72 May 15 '12 at 5:34