Final answer:
Neap tides occur during the quarter moon phases, which include the first and last quarters where the Moon appears as a half moon. At these times, the gravitational forces of the Moon and the Sun are perpendicular, resulting in more moderate tides known as neap tides.
Step-by-step explanation:
Neap tides occur when the gravitational forces of the Moon and the Sun are at right angles to each other relative to the Earth. This typically happens during the quarter moons, also known as the first and last quarter phases of the moon, when the moon appears as a half moon in the sky. So, the main answer to when neap tides occur is during a quarter moon.In more detail, neap tides result in smaller tidal ranges compared to spring tides because the gravitational pull of the Sun partially cancels out the gravitational pull of the Moon. The explanation is that during a quarter moon, the Moon's position forms a 90-degree angle with the Earth-Sun line, leading to less extreme high and low tides, which are the signature of a neap tide scenario. Hence, neap tides are not associated with the alignment that produces spring tides during the full moon or new moon phases.In conclusion, neap tides are the least pronounced tides and they occur during the quarter moon phases, when the gravitational forces of the Moon and the Sun work against each other to a certain extent.