How can we help?
You can also find more resources in our
Select a category
Something is confusing
Something is broken
I have a suggestion
What is your email?
What is 1 + 3?
Vocab of Chapter 21 The Sun-Earth-Moon System
What shape is Earth?
How would you describe this shape?
It bulges at the equator and flattens at the poles
Imaginary line around which Earth spins
How long does one complete Earth rotation take?
What are the names of Earth's poles?
The north and south poles
yearly orbit of the Earth around the Sun
elongated, closed curve; describes Earth's revolution path
The ________ between Earth and the Sun changes during Earth's yearlong orbit.
Earth's axis is tilted ___ _______ from a line perpendicular to its orbit
What does this tilt cause?
When the Sun is directly above the equator
Solstice-the point at which the Sun reaches its greatest ________ north or south of the equator.
What causes changes in the moon's appearance?
Revolution of the Moon
How often does the Moon rotate on its axis?
How long does it take the Moon to revolve once around Earth?
the changing appearances of the Moon as seen from Earth.
Moon phase that occurs when the lighted half of the Moon faces the Sun and the dark side faces Earth.
occurs shortly after New Moon, when more and more of the Moon's lighted side becomes visible.
24 hours after the New Moon, you can see a thin slice of the side of the Moon that is lighted by the Sun.
When half the Moon is lighted by the Sun for the first time in the cycle after the New Moon.
More than one quarter of the Moon is visible before a Full Moon.
When all the side of the Moon facing the Earth is lit by the Sun.
Occurs after a Full Moon, when the amount of the Moon's lighted side that can be seen becomes smaller