Translations:AY Honors/Oceans/Answer Key/78/en

The sun affects the tides in the same way that the moon does, but the sun has a much lesser pull on the oceans than the moon does, because it is much farther away, and therefore the effect is much smaller. But it does have an effect, which is what accounts for the the neap and spring tides. When the sun and moon are 90 degrees apart, they do not work together to reinforce the tidal effect. One of them will be trying to cause a high tide, and the other will be trying to cause a low tide, so the high tide is not as high, and the low tide is not as low (a neap tide). When the sun, moon, and earth are in a straight line, they do work together to make the high tides higher, and the low tides lower, thus giving us the spring tide. Therefore, we get a spring tide when we have a new moon (when the moon and sun are both on the same side of the earth) and when we have a full moon (when the sun and moon are on opposite sides of the earth). The neap tides occur at the first quarter moon and three quarter moon.