1. The Reasons for the Seasons
Bell ringer- What causes the Earth to have seasons?
The moons revolutions around the Earth.
The Earths rotation around the sun.
The Earth’s revolutions around the sun.
The tilt of Earth on its axis and it’s revolution around the sun.

2. Objectives for
GLE Describe the relative distance of objects in the solar system from earth.
GLE Illustrate the relationship between the seasons and the earth-sun system.
The students will draw a diagram of the sun and earth displaying all of the seasons.
Similar to something like this:

3. Lets Review Everyone stand up and push your chairs in.
Depending on what I say, when I say rotate” or “revolve” you will spin one time or begin walking around your desk.
We modeled this last week during an activity in class.

4. Rotation of the Earth
The earth rotates about an imaginary line that passes through the North and South Poles of the planet.  This line is called the axis of rotation. 

5. Rotation of the Earth
It is for this reason, that it seems that the sun:
Rises in the East
Is south at noon
Sets in the West
This axis is tilted 23.5 degrees
The rotation occurs from west to east over a hour period
Speed of rotation = 1700km/hr at the equator, but varies by latitude due to Earth’s spherical shape

6. Rotation of the Earth This rotation causes the cycle of day and night
Since Earth is round and opaque, the sun can only illuminate one side at a time
This is why when it is
daytime in America, it is night in Australia

8. We’re Half Way Using the white boards, drop me a picture of….
The Earth and the Sun
The Earth tilted on its axis
Draw arrows showing it rotating and revolving around the sun.

9. Revolution of the Earth
The Earth also turns around the sun in a path called an ORBIT at a speed of 29.75km/s
It takes days for one complete revolution (a solar year)
Every 4 years the extra day is added to the calendar as February 29, this type of year is called a LEAP YEAR.

10. Revolution of the Earth
Because the Earth’s axis is tilted, our planet is in different positions during the year, giving us different seasons

12. Revolution of the Earth
The seasons are marked by solstices and equinoxes
— astronomical terms that relate to Earth’s tilt.
The solstices mark the points at which the poles are tilted at their maximum toward or away from the sun.

13. Revolution of the Earth
Summer solstice
shortest night of the year
sun is farthest north
first day of summer
June 21 in Northern hemisphere

14. Revolution of the Earth
Winter solstice
longest night of the year
Sun is farthest south
first day of winter
December 21 in Northern hemisphere

15. Revolution of the Earth
The equinoxes occur when the Earth is between solstices, it is spring and fall
Day and night have almost same duration all over the planet
Equinoxes occur on March 21 and September in the Northern Hemisphere

16. Why is it hot at the equator and cold at the poles?
At the equator, the sunlight hits the Earth’s surface at a 90˚ angle, which results in a more concentrated amount of sun in a given area.
At the poles, the same amount of sun is shining but not at a 90˚ angle.
The rays therefore get spread out over a larger area, making the sun less strong over any given area.

17. Around and Around We Go Fun Fact
Every second, that you sit in this classroom, the Earth's orbital motion carries you about 18 miles through space.

18. Identify the motion being shown in each of these pictures
Identify the motion being shown in each of these pictures. Each team must write their answers for each figure in the form of a question.
Figure #1
Rotation
Revolution
Planet
Round Two
Figure #2
Earth
Rotation
Revolution

19. Round One 1. The Earth spinning on its axis.
Rotation
Revolution
2. Going around a larger body.
Rotation
Revolution
Revolution
3. 24 hours.
Round One
Rotation
Revolution
4. Causes the Earth’s seasons.
Rotation
Revolution
5. Creates a year.
Rotation
Revolution
6. The moon going around Earth.
Rotation
Revolution

20. Quick Questions Use your white board to answer these three questions.
1. How long does it take the Earth to revolve around the sun?
2. Which direction does the Earth revolve around the sun?
3. What happens to the day when an equinox occurs? (season, and effect on the day)

21. Summarizer
On a half sheet of paper, draw a model of the sun and earth during all four seasons. Show how the earth is tilted on its axis, revolving, and rotating around the sun.
Label-summer, fall, winter, spring, sun, axis, equator