The Reasons For the Seasons
Need a fun way to incorporate some physical activity in your weather & earth systems lessons? The Reasons of the Seasons created by M. J. Krech gives your students an engaging and active way to learn about the earth’s seasons.
Students will physically demonstrate the tilt and orbit of the earth in order to understand the conditions that create our seasons on earth.
A common misconception regarding the seasons is that the summer season is caused when the earth moves closer to the sun, and winter is caused when the earth moves farther away. In fact, we are physically closer to the sun during the winter months of the year. Earth does not orbit in a perfect circle, but rather in an elliptical, oval shape. The earth’s closest distance from the sun, known as perihelion, occurs around January 3. The farthest point we reach from the sun, known as aphelion, occurs around July 4.
In order to fully understand the earth’s seasons, it is important to understand the tilt of the earth’s axis. Earth does not stand straight up, but on a 23.5 degree tilt from its plane of orbit. This tilt means that during certain months, the southern hemisphere experiences warmer temperatures while the northern hemisphere experiences colder temperatures. The tilt itself does not change directions as it orbits around the sun every year.
The tile of the earth during different parts of the year affects how much direct sunlight a hemisphere receives on a daily basis. For the northern hemisphere that receives hotter temperatures during the summer months, the tilt of the earth faces them more directly towards the sun. On the other hand, those countries in the southern hemisphere will receive less direct sunlight during those months. More direct sunlight and longer days leads to hotter average temperatures, and thus a warmer summer season.
What You’ll Need
M. J. Krech created a great handout that you can use in your own classroom at The Reasons for the Seasons. This handout includes four major related activities. For these activities, you will need the following:
- 4 globes
- Soft white light bulb on a stand
- Extension cords
- 4 flashlights
- 4 sets of “seasons cards”
- 4 laminated black cards with 1 inch holes in the center
- M&M’s or beans
- Printed copies of pages 3-7 for student groups
What to Do
Your first step should be to find a large enough indoor space for groups to move around comfortably. Here are the steps for the four activities provided by the author. I will provide the basic instructions to give you an idea of what the activity entails. You should refer to the PDF for more detailed instructions.
- Place a lamp fixture in the center of your classroom.
- Tape the electric cord to the floor.
- Remove the shade and place a large soft white bulb in the lamp.
- Turn on the lamp and turn off the classroom lights.
- Have student teams (four is good) hold an Earth globe and walk around the lamp (sun) modeling the orbital path of the Earth. Each team can walk as a team.
- Have teams place large colored laminated cards on the classroom floor with
the dates and names of the spring and fall (autumnal) equinox and the
summer and winter solstice.
- Quiz Teams on various aspects of this set-up, such as:
- What Season are you at now, Team One?
- How do you know?
- Are we closer or farther away for this season?
- What season is the Southern Hemisphere experiencing now?
- How do you know?
- At what angle is the Earth pointing toward the Sun?
- What is the Special Day called? Date of that Day?
- Now, turn off the lamp and have the Teams turn on the flashlights,
which now represent the Sun.
- The Teams hold the globe 3 feet away from the flashlight and place the
black laminated card with the one inch hole between them.
- Adjust the distances so the flashlight shines a one inch beam of light on the
equator. Have the Teams measure the size of the beam of light on the globe
to be sure. [The shape should be a perfect circle – 1 inch across.] This is
called Direct Sunlight.
- Slowly tilt both the flashlight and cardboard to move the light beam
away from the equator toward the Tropic of Cancer or Capricorn, being
careful not to change their relative positions. Have students measure
the size of the light beam as it moves north or south. [The shape should
be an oval, larger than 1 inch across.] This is called Indirect Sunlight.
- While the new location receives the same amount of light (solar energy),
what happens to the light’s size and shape, and thus Intensity as it moves
away from the equator? [It increases in size, thus decreasing the amount of
solar energy in any one area.]
- Shine the flashlight directly at the grid on this page, at right angles, from a
height of about 15 cm. Trace the lighted area with a pencil. Label #1.
- Change the angle of the flashlight to about 30 degrees. Hold the flashlight at about 15 cm above the paper. Trace the area. Label #2.
- Use the following steps to measure the amount of sunlight traced on the grip paper
After completion of the first three activities, instruct your students to answer these questions individually or as a group:
- If the flashlight were sunlight, which angle would heat the paper the most?
- In general, where would the world have higher temperatures?
- Refer to a world map and list at least 6 different countries you think would have
the highest temperatures on the planet:
- If the flashlight were sunlight, which angle would heat the paper the least?
- In general, where would the world have lower temperatures?
- Refer to a world map and list at least 6 difference countries you think would
have the coldest temperatures on the planet:
- How would the angle of sunlight affect the temperature of the lighted area?
As the angle of the sunlight increases,
the temperature of the lighted area _______________
- Which lighted area (90o or 30o) would be called direct sunlight? ________________
Indirect sunlight? _______________
- Compare Jefferson City to Miami, Florida, using what you’ve learned in this lab.
- Compare Jefferson City to Toronto, Canada, using what you’ve learned in this
I’ve had the opportunity to implement this activity with my own students. My students enjoyed the opportunity to get up and move around and they showed a lot of enthusiasm for this particular activity. I find that kinetic activities are a great way to reinforce concepts or help those learners who learn by doing rather than by watching or listening.
In order to implement this successfully, it is important to plan and organize the logistics of the activity beforehand. It can be easy for kinetic activities like these to get clumsy or clustered, so it is important to plan out the logistics beforehand. It is also important to have enough space for the needs of your class in order to avoid any physical injury.
Connecting Concepts (NGSS)
- Develop and use a model of the Earth-sun-moon system to describe the cyclic patterns of lunar phases, eclipses of the sun and moon, and seasons.
Disciplinary Core Ideas
ESS1.A: The Universe and Its Stars
- Patterns of the apparent motion of the sun, the moon, and stars in the sky can be observed, described, predicted, and explained with models.
ESS1.B: Earth and the Solar System
- This model of the solar system can explain eclipses of the sun and the moon. Earth’s spin axis is fixed in direction over the short-term but tilted relative to its orbit around the sun. The seasons are a result of that tilt and are caused by the differential intensity of sunlight on different areas of Earth across the year.