Final answer:
Tides are caused by gravitational forces from the Moon and Sun creating tidal bulges on Earth. Earth's rotation and the Moon's orbit lead to twice-daily high tides, with the positions of the Moon and Sun affecting tide heights, resulting in equatorial and tropical tides.
Step-by-step explanation:
The tides are a phenomenon occurring as a result of the gravitational pull exerted by the Moon, and to a lesser extent, the Sun on Earth's oceans. Water on Earth's surface forms two tidal bulges: one facing the Moon and one on the opposite side. As Earth rotates, any given point on the surface passes through these bulges, experiencing high tides twice a day.
In addition to Earth's rotation, the complicated movement of both the Earth and Moon contributes to the variation in tide heights. As the Moon orbits Earth approximately every 28 days in the same direction as Earth's rotation, it slightly alters the timing and height of the tides. When the Sun aligns with the Moon and Earth during new and full moons, their combined gravitational pull results in higher tides called spring tides, while during the first and third quarters of the Moon, lower tides called neap tides occur.
Thus, the changing positions of the Moon and its interaction with the Sun are responsible for the differences in tide heights. Additionally, the shape of coastlines and ocean basins also affects the actual ocean tides, creating complexities in the tidal patterns that are observed as equatorial tides and tropical tides.