Rotation &

Revolution

http://studyjams.scholastic.com/studyjams/j

ams/science/solar-system/day-on-earth.htm

Astronomy The study of the moon, stars and other objects

in space.

Axis

The imaginary line that passes

through the Earth’s center and the North

and South poles.

23.5° angle/tilt

Rotation

Earth’s rotation, or spin, on its axis (23.5)

causes day or night.

Night & Day

• The Earth rotates on it’s axis every 23hrs and 56 mins (almost 24 hrs)

• The sun shines on only ½ of the Earth at a time. – ½ of the Earth is

experiencing night time. While the other ½ is in daylight!

What Is Rotation?

• For every complete rotation one day has passed.

Earth spins

counter-

clockwise.

Sunset from space

Orbit

–Earth’s path as it revolves

around the sun.

–Earth’s orbit is not circular. It

revolves in an oval shape called elliptical

•Revolution or orbit –The time it takes for the earth to make

one complete revolution around the sun is called a year.

One Revolution = 365.25 days or

One Year

- This is why we have a leap year every 4

years!

Revolution Causes changes of the

seasons?

Seasons are caused by 1. Earth’s revolution around

the Sun

2. the unchanging tilt of the Earth’s axis.

Common Misunderstandings:

Earth’s changing distance to the Sun does not cause seasons!

The north pole tilts towards the sun

It is Summer time in countries in the Northern Hemisphere.

It is Winter time in countries in the Southern Hemisphere.

One more time…We have seasons because:

1. The tilt of the Earth’s axis

2. The revolution of Earth around the Sun.