1. How does our journey through space cause days, years, and seasons?
As the World Turns
How does our journey through space cause days, years, and seasons?

2. Rotation
Earth rotates on its axis once every 24 hours. We call this one day.
When your part of the earth faces the sun, you experience day. What happens to cause night?

3. East West
Sun appears to rise in the east and set in the west because the Earth turns on its axis from west to east.

4. Revolution
The path the Earth takes around the sun is called it’s revolution. It takes us days to travel around the sun. We revolve around the sun counterclockwise.

5. Moving through Space
The Earth revolves around the Sun at a rate of about 67,000 miles per hour
We are also moving through space with our solar system and the Milky Way Galaxy
We don’t feel how fast we are moving because we have no way to sense the movement

6. Seasons
Are caused by the tilt of the Earth’s axis, which is at an angle of 23.5 degrees
Each season lasts 3 months
Equator is the line that divides the Northern and Southern Hemispheres
The hemisphere tilted toward the sun gets more direct light
There are four special times during the year.

7. +
Solstices
Summer Solstice – sun’s rays hit as far north as the tilt will allow – occurs in the month of June
Winter Solstice – sun’s rays hit as far south as the tilt will allow – occurs in the month of December

8. Observing Solstices
The Summer and Winter Solstices have been important to mankind for a long time. Stonehenge is aligned to measure the solstices.

9. Equinoxes
Vernal Equinox in March and the Autumnal Equinox in September; Equinox means “equal night”. These were considered the two days of the year where daylight and nigh time hours were equal. Now refers to the days the center of the sun is directly above the equator.

11. Many people believe we have summer because we are closer to the sun in the summer. Look at the diagram and explain why they are wrong!

12. Questions?