EARTH IN MOTION
This movement of Earth causes day and night.
What is rotation?
This imaginary line runs through Earth's North and South Poles.
What is Earth's axis?
This type of sunlight strikes Earth's surface more directly and concentrates energy over a smaller area.
What is direct sunlight?
These are the four major seasons.
What are spring, summer, fall, and winter?
What part of Earth experiences daytime?
The part facing the Sun.
This is the time Earth takes to complete one rotation.
What is about 24 hours?
Earth's axis is tilted approximately this many degrees.
What is 23.5°?
This type of sunlight strikes at a lower angle and spreads energy over a larger area.
What is indirect sunlight?
This event occurs twice a year when day and night are approximately equal in length.
What is an equinox?
What causes day and night on Earth?
Earth's rotation.
This movement is Earth's trip around the Sun.
What is revolution?
This word describes one half of a sphere, such as the Northern or Southern half of Earth.
What is a hemisphere?
Which type of sunlight generally heats Earth's surface more effectively: direct or indirect?
What is direct sunlight?
This event marks the longest or shortest period of daylight of the year in a hemisphere.
What is a solstice?
If it is daytime on one side of Earth, what is happening on the side facing away from the Sun?
It is nighttime.
Earth takes approximately this long to complete one revolution around the Sun.
What is 365.25 days? 365 is accepted
When the Northern Hemisphere is tilted toward the Sun, what season does it experience?
What is summer?
During which season does the Northern Hemisphere experience the fewest hours of daylight?
What is winter?
During which solstice does the Northern Hemisphere experience its longest day of the year?
What is the summer solstice?
During an equinox, how does the length of day compare with the length of night in most places?
They are approximately equal.
Earth is rotating and revolving at the same time. Explain what each movement causes or determines.
Rotation causes day and night; revolution, combined with Earth's tilt, determines the yearly cycle of seasons.
Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere?
Because Earth's tilt causes the hemispheres to receive different angles of sunlight and different amounts of daylight at the same time.
As the Northern Hemisphere moves from winter toward summer, what happens to the number of daylight hours, and why?
Daylight hours increase because the Northern Hemisphere gradually tilts more toward the Sun.
Earth is closest to the Sun during Northern Hemisphere winter. Why doesn't this make winter warmer than summer?
Because seasons are caused mainly by Earth's tilt, which affects sunlight angle and the number of daylight hours.
A student says, “The Sun moves around Earth, causing day and night.” Explain why this statement is incorrect.
Earth rotates on its axis, causing different parts of Earth to face toward or away from the Sun.