Question

If the Moon is over the same spot on Earth only once per day, why are there two high tides per day?​

Answer 1

When the moon is over a spot on the earth, the gravitational pull causes the high tide. Just the same, when the moon is on the other side of the planet, the water rises. The water that isn't in direct contact is being compressed by the gravitational pull, causing the water facing the moon, and the water on the direct opposite side of earth to bulge.

Step-by-step explanation:

Answer 2

It's what's left over after removing the Moon's average gravitational pull on the whole planet from the Moon's specific gravitational pull at each location on Earth.