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.

Answer:

Spring tides occur during the new and full moon phases when the Sun, Earth, and Moon are aligned in a straight line. In this position, the combined gravitational pull of the Sun and the Moon acts on Earth’s crust and ocean water, leading to higher than normal high tides and lower than normal low tides. Neap tides occur during the first and third quarter moon phases when the Sun and Moon are at right angles to each other relative to Earth. Because the gravitational pulls of the Sun and Moon offset each other, the tidal range is minimized, resulting in lower high tides and higher low tides.