Motions of the Earth

Chapter 5Lesson 2 Earth and the Sun

Motions of the Earth

• If you watch the Sun for several hours, you will notice that it looks like it moves across the sky.

• Does the Sun move across the sky?

Motions of the Earth

• The Sun only seems to move, because the Earth is rotating, or spinning like a top.

• Earth spins, or rotates, around its axis.• What is Earth’s axis?

Motions of the Earth

• Earth’s axis is an imaginary line that runs from its North Pole, through its center, to its South Pole.

Motions of the Earth

• The Earth spins at just over 1,000 miles an hour.

• We can’t feel it spinning. • Earth completes one rotation in about 24

hours.• As a result of this movement, Earth has

day and night.

Motions of the Earth

• As Earth spins only one side faces the Sun.

• Day begins when our part of the world turns to face the Sun.

Motions of the Earth

• Night falls when our part of the Earth turns away from the Sun.

• The side facing away from the sun has nighttime.

1. We know the Earth is spinning from data gathered by satellites

HOW DO WE KNOW THAT EARTH IS SPINNING?

2. French scientist Foucault• Created a pendulum that swung back and

forth in one direction.• Pegs were arranged in a circle around the

ball• Over a period of a day, the pegs were

knocked down.• Earth rotated under the ball

HOW DO WE KNOW THAT EARTH IS SPINNING?

HOW DO WE KNOW THAT EARTH IS SPINNING?

3. The shape of the Earth is also proof that Earth is spinning

• Earth is slightly flattened at the North and South Poles

• It also bulges at the equator• As Earth spins, Earth’s matter is thrown to the

“edge”

HOW DO WE KNOW THAT EARTH IS SPINNING?