Abstract

When students learn about Earth-Sun relationships from models of the solar system, they discover that Earth's axial tilt is the cause of variable sun angle and the seasons. However, they experience this using an "eye in the sky" perspective that is not accessible through personal experience. Making the mental translation to a view from Earth is a spatially difficult task. This project engages students in recording spatio-temporal, personal observations of the sun in a way that is relevant and exciting. Activities include learning about a "mind-blowing ancient solar calendar", interacting with sun path and ecliptic simulators, and creating a montage of sunset pictures with solar angle measurements that beautifully display their observations.
Students will:
- observe that the length of the path of the Sun across the sky, and hence the length of day change in a predictable pattern over the course of a year; 

- notice that the elevation angle of the Sun in the sky, and hence the sun angle changes in a predictable pattern over the course of a year; 

- recognize that varying sun angle and length of day change the intensity and length of exposure to the Sun, thus affecting temperature and causing seasonal change. 


Context

I use this activity in an introductory level atmospheric science course that I teach to undergraduate students majoring in elementary education. I also published a version of the activity intended for middle school students in Science Scope, NSTA's peer-reviewed journal for middle level and junior high school science teachers. It is a hands-on, observational way to teach how fluctuating sun angle and length of day determine the amount of solar radiation, or insolation, that Earth receives. In addition to applications in atmospheric science, this lesson could be used in astronomy courses, general Earth science courses, and to teach the reason for the seasons. It can be also be modified for different levels, including K-12.

Why It Works

The highlight of the activity is the personal observations. Students take monthly photos of the sun along the horizon at sunrise or sunset. They also make monthly sun angle measurements of the sun at solar noon using homemade clinometers. Students assemble this evidence with a written explanation of how the sun's position along the horizon and sun angle changes throughout the year and how this affects insolation. The innovative use of an Earth (versus space) perspective effectively frames students' understanding in a relevant way that fosters "aha moments". By engaging with the natural world students connect with science authentically, promoting scientific thinking. This activity is worthwhile because it kindles interests and encourages students to purposefully seek connections between their personal experiences and the science classroom.