What causes tides to rise and fall?

Tides rise and fall due to the gravitational pull of the Moon and, to a lesser extent, the Sun. The Moon’s gravity causes water to bulge on the side of Earth closest to it, while centrifugal forces create a similar bulge on the opposite side. As Earth rotates, these bulges move, creating high and low tides. The timing and height of tides vary depending on the position of the Moon and local geography.