Final answer:
The water on Earth's surface bulges towards the moon due to gravitational attraction. The Moon's gravitational force varies with distance, causing differential pull on Earth's waters and forming tidal bulges.
Step-by-step explanation:
The force that primarily causes the water on Earth's surface to "bulge" toward the moon is gravitational attraction. This phenomenon occurs because the gravitational force that the Moon exerts on Earth diminishes with the square of the distance from the Moon. Therefore, water on the side of Earth nearest to the Moon experiences a stronger gravitational pull than the water at the center of Earth, which in turn experiences a stronger pull than the water on the side of Earth farthest from the Moon. This differential in the gravitational pull causes the water to elongate and form tidal bulges, both on the side facing the Moon and on the opposite side, resulting in what's known as tide-raising forces.