Reason for the Seasons

Many people incorrectly believe that the reason the average temperatures are colder during the winters and warmer during the summer is due to the changing distance between the Earth and the Sun. This simply is not true. In fact, the surface of the Earth in the Northern Hemisphere is closer to the Sun during winter than summer because of Earth's elliptical orbit. In this activity, students will create a storyboard that explains why we have seasons.

The Earth rotates about an axis, or imaginary line that runs through the center of the Earth. The Earth’s axis is not perfectly straight up and down; it is about 23.5° off the vertical. This means the South and North Pole face towards and away from the Sun as Earth makes its way around the Sun during the year. During summer months, the Sun’s rays hit the hemisphere more directly, so the rays are spread over a smaller area. During winter months, the opposite happens, and the rays from the Sun are less concentrated.

After completing this activity, there's a great opportunity for students to evaluate their models. Lead students through pointing out the strengths and limitations of the models by giving them an opportunity to make suggestions for improvements.

Student Instructions

Make a storyboard to explain what causes seasons on Earth. Use a series of scenes, props, labels, and shapes to create a model to explain the existence of seasons. Explain summer and winter in both the Northern and Southern Hemispheres.

1. Click "Start Assignment".
2. Create a diagram with Earth and the Sun.
3. Use arrows, lines, and shapes to show how sunlight reaches Earth.
4. Explain what causes summer and winter in the description box.