Tides in the oceans are primarily caused by the gravitational pull of the moon and the sun on the Earth. The gravitational force of the moon is stronger than that of the sun because it is closer to our planet. As the Earth rotates on its axis, the gravitational pull of the moon and the sun causes bulges of water on the side of the Earth facing them and on the opposite side as well. These bulges of water create high tides. Low tides occur in between these high tides when the water is drawn away to create the bulges. The alignment of the Earth, moon, and sun also affects the intensity of tides, resulting in spring tides (higher high tides and lower low tides) and neap tides (lower high tides and higher low tides).