1. Once Around the Sun
The Story of the Seasons
A WindShadow Production

2. The Earth orbits around the sun once every 365 days.
The Science
The Earth orbits around the sun once every 365 days.
An orbit is the path that a planet follows around the sun.

3. one revolution
We also keep track of how many times we go around the sun. One complete trip is a revolution.

4. The sun is so far away the rays that hit the Earth are parallel.
axis
equator
Because the Earth is tilted on its axis we have seasons.

5. that receive the more indirect rays are cooler.
So that different parts of the Earth receive the Sun’s rays at different angles.
The Earth tilts
on its axis.
axis
Summer
equator
Winter
The parts of the Earth
that receive the more
direct rays are warmer.
The parts of the Earth
that receive the more indirect rays are cooler.

6. We will start our seasons here.
It is the Vernal Equinox, March 20 or 21.
The start of spring. .

7. we have a change of season.
summer
Summer Solstice
After the Earth has
traveled 1/4 of the way
around its orbit
we have a change of season. .

8. It is the Summer Solstice, June 21 or 22, .
It is the Summer Solstice, June 21 or 22,
the longest day of the year and the shortest night.
Summer begins.

9. equator
axis
warmer
colder
summer
Summer Solstice
The Earth’s axis is tilting towards the sun and the Northern Hemisphere starts to get warmer. .

10. we have another change of season.
Autumnal Equinox
autumn
After the Earth has
traveled 2/4 or halfway
around its orbit
we have another change of season. .

11. The Autumnal Equinox occurs on September 22 or 23, .
The Autumnal Equinox occurs on September 22 or 23,
day and night are of equal length.
Autumn begins.

12. axis . . . . . . . . . .
equator . . . . . . . .
Autumnal Equinox
autumn .
The Earth’s axis is tilting so that the Northern and Southern Hemisphere receive equal amounts of the sun’s rays.

13. After the Earth has traveled 3/4 of the way around one revolution
Winter Solstice
winter
After the Earth has traveled 3/4 of the
way around one revolution
we have a third change of season. .

14. the shortest day of the year and the longest night, occurs on
Winter Solstice
winter .
The Winter Solstice,
the shortest day of the year and
the longest night, occurs on
December 21 or 22.
Winter begins.

15. equator
axis
winter
summer
winter
Winter Solstice .
The Earth’s axis tilts the Northern Hemisphere away from the direct rays from the sun so it receives less energy.

16. After the Earth has traveled
spring
Vernal Equinox
After the Earth has traveled
for one complete revolution around the sun we are back where we began. .

17. It is the Vernal Equinox, day and night are equal in length.
spring
Vernal Equinox
equator
It is the Vernal Equinox,
day and night are equal in length.
Spring begins, again. .

18. the reason for the seasons.
The tilt of the Earth is
the reason for the seasons.
autumn
summer
winter
spring

19. Choose the words that belong in the sentence.
In a 365 day period, the Earth completes
one in its
a. rotation, axis
b. rotation, orbit
c. revolution, axis
d. revolution, orbit

20. Look at the illustration below.
equator
axis
What season is the location the arrow is
pointing to on the Earth experiencing?
a. spring
b. winter
c. autumn
d. summer

21. Look at the illustration below.
equator
axis
What season is the location the arrow is
pointing to on the Earth experiencing?
a. spring
b. winter
c. autumn
d. summer

22. The Math orbit geometry What geometric shape is the orbit? Art - oval
Math – ellipse

23. The Math orbit geometry What geometric shape is the sun and Earth?
Math – sphere

24. The Math seasons’ time How long is one revolution?
Math – 365 days – 12 months – 1 year

25. The Math seasons’ time How long is one season?
Math – ~91 days – 3 months – ¼ year

26. The Math geometry How would we describe the sun’s rays?
axis
geometry
equator
How would we describe the sun’s rays?
Math – parallel
How would we describe the angle made by
the equator and the axis?
Math – perpendicular, intersecting, 90 degrees

27. The Math geometry What is the geometric name for the equator?
axis
geometry
What is the geometric name for the equator?
Math – circle
What would we call it if it just went through the
center of the Earth?
Math – line segment -
diameter