Science Minutes DVD
Episode 4: Seasons
Focus Question: What causes Earth’s seasons?
Standards
National Science Standard
- Content Standard B: Physical Science (Grades 5-8)
- Content Standard D: Earth and Space Science (Grades 5-8)
Next Generation Sunshine State Standard
Grade 5: | SC.5.E.5 Earth in Space and Time |
Benchmark SC.5.E.5.3 | |
SC.5.E.7 Earth Systems and Patterns | |
Grade 6: | SC.6.E.7 Earth Systems and Patterns |
Grade 8: | SC.8.E.5 Earth in Space and Time |
Benchmarks SC.8.E.5.7, SC.8.E.5.9 |
Vocabulary
Axis a straight line about which a body or geometric figure (as in the earth) rotates or may be supposed to rotate; the earth’s axis runs from the north to south poles
Equator a great circle of the earth or a celestial body that is everywhere equally distant from the two poles and divides the surface into the northern and southern hemispheres
Northern Hemisphere the half of the earth that lies north of the equator
Rotation the action or process of making one complete turn on or as if on an axis or center
Season one of the four quarters into which the year is commonly divided; a period of the year characterized by a particular type of weather, activity or phenomenon
Southern Hemisphere the half of the earth that lies south of the equator
Classroom Activity
Supplemental Links
- Enchanted Learning: The Seasons and Axis Tilt, www.enchantedlearning.com/subjects/astronomy/planets/earth/Seasons.html
- Science U: Season Reasons, www.scienceu.com/observatory/articles/seasons/seasons.html
Further Investigation with Online Activities
- Science for Ohio: The Reason for the Seasons,
http://casnov1.cas.muohio.edu/scienceforohio/Seasons/L.html
Oral Assessment
Transcript
Kasey
Anyone out there know what causes the seasons? Well here is a pop quiz.
The reason for the seasons is: A. because the earth is closer to the sun; B. because the earth is farther away from the sun; C. both A and B; or D. none of the above. Correct answer: D. none of the above.
The reason for the seasons is actually caused by the orbit and tilt of the earth as it goes around the sun. Don't believe me? Check this out.
You see, the earth is a planet spinning in space and orbits around a bright yellow star, which is the sun of course. Now imagine a line from the north pole to the south pole. That line is called the axis of the earth.
The earth sits at kind of a funny angle. To be more precise, a 23.5 degree angle, which is why see a globe it is tilted on its side. It is this angle which is the reason for the seasons.
Each time the earth rotates on its axis, that equals one day. And each time the earth orbits the sun, that equals one year.
But notice what is happening at the bottom of the globe. There's less light reaching the southern hemisphere. So it's wintertime down under.
And when we get around to December 22, the situation is completely reveresed. That means more direct light is hitting the bottom of the globe than the top. So now it's summer down here and winter up here.
So to make a long story short, it's the angle of the earth that affects how much light different parts of the earth get through out the year. And this, my friends, is the real reason for the seasons.