This interactive is used in Chapter 2.
That our seasons come from the tilt of Earthâs axis relative to its orbit of the Sun is easy to grasp, once you have used this Interactive. It shows the flow of seasons as the planet orbits the Sun, the angle of the Sunâs rays for a given location on Earth, how temperature varies at that location, and how the Sunâs path varies in the sky by season. Choose from 3 planets to see how their seasons reflect their unique tilts, or customize the tilt. What would âwinterâ be like if Earth had no tilt? This Interactive will show you.
Source
http://highered.mheducation.com/sites/007299181x/student_view0/interactives.html#