Spaghetti and Tinkercad Models of the Seasons

Introduction: Why is it hotter in the summer than in the winter? The answer has to do with the arrangement of the sun and earth in our solar system. But there are a lot of misconceptions about this! These models can help visualize what happens over a year.

Background: The most common misconception about seasons is that it is warmer in the summer since the earth gets closer to the sun. In fact, while the orbit of the earth is slightly elliptical, the earth is a bit closer to the sun during our winter. Besides, half of the earth is always experiencing the opposite season. So what is happening? The models below can help students visualize the reason for summer and winter. No one model is perfect for all aspects of the solar system. For example, these models are totally inaccurate in terms of relative sizes and distances. It is best to use several different models and simulations, and discuss their strengths and shortcomings.

Supplies

The Tinkercad model can be found at: https://www.tinkercad.com/things/h3toWtwOgwK

For the spaghetti model, you will need a small sheet of corrugated cardboard and about 20 pieces of spaghetti. A small cardboard box can serve as a base.

Step 1: ​Tinkercad Model

Seasons have to do with the tilt of the earth’s axis combined with the position of the earth in its yearly orbit around the sun. Here it is shown in a Tinkercad model: https://www.tinkercad.com/things/h3toWtwOgwK

Count up the “light rays” that are hitting the earth above the equator in the picture on the left (summer in the northern hemisphere). Six months later the earth has gone halfway around in its yearly orbit of the sun. Now count the “light rays” hitting the earth above the equator in the picture on the right. Why is this significant? More light means more energy from the sun — the light warms the sections of the earth it is falling on and more light equals more heat. If there is less light spread out over the same area, it means less energy and it is colder. The Northern and Southern hemispheres are always the same size, but the amount of light (energy) they get depends on where we are in our yearly orbit of the sun.

Of course, the earth is also rotating around its axes, so day and night are a separate daily cycle superimposed on the yearly orbit around the sun. The half of the earth that is in the dark tends to cool off somewhat during the night but then gets warmed up again the next day.

In the model the earth has 8 segments. You can also count the number of “light rays” hitting a segment near the equator, versus a segment near a pole. The tropical latitudes also get more energy from the sun relative to the latitudes nearer the poles. How would this affect the temperature?

Using the Tinkercad model: In the Tinkercad model you can “fly” around the model in three dimensions. To visualize summer and winter, go to the Home view, then select the earth (a grouped object) and simply drag it around the sun in a rough orbit to the other side. Then return to the Front view to count the light rays that hit above or below the equator. (Keep in mind that the direction of the earth's axis stays the same — so do not rotate the earth in the model, or move the earth up or down out of the plane of its orbit.) To visualize the position 6 months later, go back to the Home view and select the earth and drag it halfway around the sun. Go to the Front view and count the light rays again.

Because the model compresses distance, students sometimes look at the model and point out that the hemisphere experiencing summer is closer to the sun than the other hemisphere. This is true, but the difference is not the cause of the seasons — the question is how much energy from the sun is hitting each hemisphere based on the geometry shown above.

Step 2: Making the Spaghetti Model of the Seasons

Students can make a physical model as well. Cut a circle of corrugated cardboard about 5.5 - 6 inches in diameter. Gently push a strand of spaghetti through every other corrugation. This yields an evenly spaced set of “light rays” that can be pushed back and forth through the cardboard. It is basically like a “contour gauge” used by woodworkers. You can leave a few spaces open on the top and bottom to make it easier to hold.

Use a styrofoam or rubber ball about 2.5 to 3 inches in diameter for the earth. You will need to push a stiff wire through the center of the ball to form the axis. It is helpful to mark the poles first and try to get the axis as centered as possible. (You can also use two pieces of wire pushing one halfway in from the North pole and one from the South pole — this makes it easier to keep it centered.) The earth's axis is tilted at 23.5 degrees so use a protractor to set the angle as best you can relative to the table or base. In terms of height above the table, the midpoint of the earth and sun should be lined up. I used a box with a folding lid as a base to hold the model earth and sun.

Step 3: Using the Spaghetti Model of the Seasons

To show the daily rotation of the earth, rotate the ball on its axis. To show the seasons, move the earth from one side of the sun, around to the opposite side. Make sure to keep the axis pointing in the same direction as you make the orbit, and keep the same distance from the sun. You can then push the spaghetti to see how many hit the earth in each hemisphere. After counting, move the earth around to the other side of the sun (showing the location 6 months later), reposition the spaghetti, and count again.

Step 4: Resources

For more information on the seasons and further links see:

https://www.loc.gov/everyday-mysteries/meteorology...

This work is made possible by support from STAR, a Biogen Foundation Initiative. The team at Lesley supporting this initiative includes faculty and staff in the Lesley STEAM Learning Lab, Science in Education, the Center for Mathematics Achievement, and other related Lesley University departments and programs.