Earth, Moon, and Sun

What is rotation?

•Rotation is…. ….the act or

process of turning around a center or an axis.

Spinning!

Earth’s Rotation Causes Day and Night

• Earth spins on an imaginary line running through its center called its axis.

Which way?• Earth spins from West to East

Do this!

• Place your right hand in front of you• Make a fist with your thumb pointed towards the

ceiling (up).• Your thumb will represent the North Pole.• Straighten your fingers and then slowly close

your fingers.• Your fingers curve the way the Earth rotates.• Weeeeeeee! (West to East)

Apparent Motion

• As the Earth spins westward the Sun and the moon appear to rise in the eastern sky.

Example of Apparent Motion

• As you drive in your car, trees appear to be moving by, but they are not, you are.

Can you think of other examples of apparent motion?

What is Gravity?• The force objects exert on each other

because of their mass…Causes objects to be pulled towards Earth’s center…Also causes Earth to be pulled towards the Sun’s center.

What is Revolution?• The motion of one object around another.

It takes the Earth one year to travel around the Sun

How long does it take Earth to spin on its axis?

• 24 hours!

• If it is noon at one location, what time is it at a location directly on the other side of the Earth?

• Midnight.☺

What are seasons?• Patterns of temperature changes and

other weather trends.

What causes temperature changes?

• The amount of sunlight at each location changes during the year

• Near the equator, temperatures are nearly the same year-round.

• Near the poles, there are large changes from winter to summer.

The Tilt is the Reason for the Season!

• Seasons are caused by the Earth’s tilted axis

• The Earth is tilted at 23°

Earth’s tilted Axis and Orbit Causes the Seasons

• As Earth moves, its axis always points in the same direction

• There is more direct sunlight during the summer and less direct sunlight in the winter in the Northern Hemisphere.