Unit 3 - Motion of Earth L4-5

Motion of Earth

How does Earth's motion cause Day and Night? How does Earth's motion cause the cycles of Seasons?

Multiple Choice

What do you think causes day and night?

• The Sun spinning around Earth

• The Earth spinning around the Sun

• The Earth spinning on its Axis

Multiple Choice

Day and Night on Earth are caused by...

• Revolution of Earth around the Sun

• Rotation of Earth around its axis

• The Revolution of the Sun around Earth.

Multiple Choice

How long is a "day" on Earth?

1 full rotation of Earth = 1 day on Earth

• 23 hours and 56 minutes

• 24 hours

• 12 hours of day time and 12 hours of night time

Length of "day" on Earth

• When you think of a day, you normally think of one cycle of daytime to nighttime. That is called a solar day. On Earth, a solar day is around 24 hours. However, Earth’s orbit is elliptical, meaning it’s not a perfect circle. That means some solar days on Earth are a few minutes longer than 24 hours and some are a few minutes shorter.

• Another way to measure a day is to count the amount of time it takes for a planet to completely spin around and make one full rotation. This is called a sidereal day. On Earth, a sidereal day is almost exactly 23 hours and 56 minutes.

Did you know?

• It takes approximately 24 hours for the Earth to turn all the way around (rotation). That makes one day and one night.

• The Earth spins around an imaginary line (axis) that runs between the South Pole and the North Pole. This line is tilted 23.5 degrees – so, sometimes the North Pole is pointing away from the sun for long periods of time and it is always dark there, and sometimes the North Pole points towards the sun for long periods of time and it is always light there.

• The Earth rotates in a counter-clockwise direction around its axis. This is why the sun rises in the east and sets in the west.

Dizzy Yet?

At Earth’s equator, the speed of Earth’s spin = 1,000 miles per hour.

Why do we not feel it? It’s because you and everything else including Earth’s oceans and atmosphere are spinning along with the Earth at the same constant speed.

Open Ended

What do you think would happen if the Earth stopped rotating? Explain your thinking.

Rotation vs Revolution

• Rotation - is a circular movement of an object around an axis.

• Revolution - is when one body moves around another.

• The Moon revolves around the Earth and the Earth revolves around the Sun while the Earth is also rotating around its axis.

Multiple Choice

How long does it take Earth to complete 1 revolution around the sun? On Earth, 1 revolution = 1 year

• 300 days

• 364 days

• 365 days, 5 hours, 59 minutes and 16 seconds.

Fill in the Blanks

Fill in the Blanks

Multiple Choice

What causes the Cycles of Seasons on Earth?

• Distance from the Sun

• Tilt of the Earth's Axis

Open Ended

What would be the effect on the seasons and the northern and southern hemispheres if Earth were not tilted? Explain your answer.

Poll

Have you completed the Reason for the Seasons Portfolio (U3-L5) yet?

• Yes

• No

Poll

Have you found the Alternative Portfolio Options for Unit 3 or know where to look?

• Yes

• No

Multiple Choice

What does ROTATION mean?

• To SPIN
• To ORBIT or GO AROUND

Multiple Choice

The MOON REVOLVES around the:

• Sun
• Earth
• The Moon doesn't revolve
• The Earth and Sun 

Multiple Choice

What does REVOLUTION mean?

• To SPIN
• To ORBIT or GO AROUND

Multiple Choice

Earth's rotation on its axis is what causes ______________________________.

• seasons
• moon phases
• day and night
• weather

Multiple Choice

The Earth spins on a tilted angle called a (an) 

• Axis
• Invert
• Revolution
• Bounce

Multiple Choice

Rotation of the earth takes

• One day
• One year
• One summer
• One winter

Multiple Choice

What motion of the Earth takes 365 days?

• Rotation
• Tilting 
• Revolution
• Spinning

Multiple Choice

Day and night is caused by the _____________ of earth on its axis.

• revolution
• orbit
• rotation
• space

Multiple Choice

The EARTH REVOLVES around the:

• Sun
• Moon
• The Earth doesn't revolve
• The sun rotates

Multiple Choice

Spinning of the Earth on its axis is called...

• rotation
• revolution
• orbit
• double axis