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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?

24 hours

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

23.5 degrees

What does this tilt cause?

The seasons


When the Sun is directly above the equator

Spring Equinox

March 20th/21st

Fall Equinox

September 22nd/23rd

Solstice-the point at which the Sun reaches its greatest ________ north or south of the equator.


Summer Solstice

June 21st/22nd

Winter Solstice

December 21st/22nd

What causes changes in the moon's appearance?

Revolution of the Moon

How often does the Moon rotate on its axis?

27.3 days

How long does it take the Moon to revolve once around Earth?

27.3 days

Moon phases

the changing appearances of the Moon as seen from Earth.

New Moon

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.

Waxing Crescent

24 hours after the New Moon, you can see a thin slice of the side of the Moon that is lighted by the Sun.

First Quarter

When half the Moon is lighted by the Sun for the first time in the cycle after the New Moon.

Waxing Gibbous

More than one quarter of the Moon is visible before a Full Moon.

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

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