Orbit & Revolution
What path does Earth follow as it moves around the Sun?
Its orbit
What is the imaginary line that Earth spins on called?
Axis
On what dates do solstices occur?
Around June 21 and December 21
On what dates do equinoxes occur?
Around March 21 and September 23
What causes the different seasons on Earth?
The tilt of Earth’s axis
How long does it take Earth to complete one revolution around the Sun?
365 days (1 year)
What does Earth’s rotation cause us to experience daily?
Day and night
Which solstice is the longest day of the year in the Northern Hemisphere?
The summer solstice (June 21)
What does the word “equinox” mean?
Equal day and night
When the Northern Hemisphere has summer, what season does the Southern Hemisphere have?
Winter
Earth’s orbit is not a perfect circle — what shape is it?
An ellipse (oval)
How many degrees is Earth tilted on its axis?
23.5 degrees
Which solstice is the shortest day of the year in the Northern Hemisphere?
The winter solstice (December 21)
What equinox marks the beginning of spring in the Northern Hemisphere?
Spring equinox (March 21)
What area of Earth receives the most direct sunlight year-round?
The equator
What does Earth’s revolution around the Sun cause?
The change of seasons
How long does one full rotation of Earth take?
24 hours
During a solstice, the Sun is farthest north or south of what line?
The equator
What equinox marks the beginning of fall in the Northern Hemisphere?
Fall equinox (September 23)
Why are days longer in summer and shorter in winter?
Because of Earth’s tilt toward or away from the Sun
If Earth weren’t tilted, what would we not experience?
Seasons
Why do solstices occur on different days between June 20–22 and December 20–23 instead of always on the same date?
Because Earth’s orbit is elliptical and doesn’t divide evenly into our calendar year.
Why are equinoxes important for farming and ancient calendars?
They signaled planting/harvest times and seasonal changes
Why does Earth’s tilt, combined with its revolution, cause seasons instead of Earth being the same all year round?
Because the tilt makes different parts of Earth receive varying amounts of direct sunlight throughout the year.