During equinox_____?

Analyze the question: It asks what happens during an equinox. The word itself helps: "equi" means equal and "nox" means night.

Explain the concept: An equinox happens twice a year, around 21 March (March equinox) and 23 September (September equinox). On these dates, the sun's vertical (overhead) rays fall directly on the Equator. The Earth's axis is tilted, but neither pole is tilted toward or away from the sun. The circle of illumination (the line dividing day from night) passes through both poles, so it cuts every line of latitude into two equal halves.

Step-by-step evaluation of the options:

• A. The Tropic of Cancer experiences longer day than the Tropic of Capricorn. Wrong. Both tropics get about 12 hours of daylight at an equinox. The Tropic of Cancer only has longer days around the June solstice.
• B. All places across the globe experience equal lengths of day and night. This is the standard textbook statement. Day and night are each about 12 hours everywhere.
• C. The length of day at the equator is shorter than at the Tropic of Cancer. Wrong. The equator has about 12 hours of day all year, and at an equinox the Tropic of Cancer has the same.
• D. The moon is star shaped all through the night all over the world. Nonsense. The moon is never star shaped, and its phase has nothing to do with equinoxes.

A small note for accuracy: in strict terms, the equality is approximate. Because of atmospheric refraction and the sun's size as a disc, day is slightly longer than night, and the poles are special cases. WASSCE, however, expects the standard answer: equal day and night everywhere.

Exam tip: Remember "Equinox = Equal night." Also link the two events to the seasons. At the equinoxes the sun is overhead at the equator, while at the solstices (21 June and 22 December) it is overhead at the Tropic of Cancer and the Tropic of Capricorn respectively.