Explain what causes spring and neap tides, and identify the phases of the moon when these tides occur. Be sure to mention what happens to Earth's crust, ocean water, and the positions of the Sun, Earth, and the moon.

Sample Response: Spring tides occur when the moon is full or new. Earth, the moon, and the Sun are in a line. The moon's gravity and the Sun's gravity pull Earth's crust and ocean water. This causes tides to be higher than normal.

At neap tide, the moon and the Sun are at right angles to each other. This happens during the first and third quarters of the lunar cycle. At neap tide, the Sun's gravity and the moon's gravity are balanced. High tides are lower; low tides are higher.

Spring tides occur when the moon is full or new ... The moon's gravity and the Sun's gravity pull Earth's crust and ocean water. This causes tides to be higher than normal. At neap tide, the moon and the Sun are at right angles to each other