Which tide occurs when Earth, Moon, Sun form a right angle, resulting in the smallest tidal variation?

• A. Spring Tide
• B. Neap Tide
• C. Slack Water
• D. Solar Tide

Answer: (B)

Tides come from the Moon’s and the Sun’s gravity pulling on Earth’s oceans. When the Sun and Moon line up with Earth, their tidal effects add and create a large vertical movement—this is a spring tide with the biggest difference between high and low water. When the Sun, Moon, and Earth are at right angles, the Sun’s tide acts at a right angle to the Moon’s tide and partly cancels it. The water bulges don’t reinforce each other, so the difference between high and low water is smallest. That situation is called a neap tide. Slack water isn’t about the geometry of the Sun and Moon, and the solar tide refers to the Sun’s contribution in general, not this right-angle configuration.