Equinox — Science definition
One of two days a year (around March 20 and September 22) when Earth's tilt is sideways to the Sun, so day and night are roughly equal length nearly everywhere.
Where it is taught
- Seasons & Earth's Tilt — Earth, Moon & Solar System, Earth & Space Science, Grade 9
Questions using equinox
Problem 1
What happens during an equinox?
- One hemisphere gets far more sunlight than the other
- Day and night are roughly equal length nearly everywhere
- Earth reaches its closest point to the Sun
- Earth's axis points directly at the Sun
Answer and explanation
Day and night are roughly equal length nearly everywhere
At the equinoxes, Earth's tilt is sideways to the Sun, so sunlight is split roughly evenly between hemispheres.
Problem 2
At an equinox
- day and night are roughly equal everywhere
- the Sun never sets
- the tilt is zero
- Earth is closest to the Sun
Answer and explanation
day and night are roughly equal everywhere
Neither hemisphere is tilted toward the Sun, so day and night are nearly equal.