Solar radiation (light) strikes Earth's surface throughout the daylight hours. Radiation (heat or infrared) also leaves the Earth during daylight and at night. Averaged over time and space, these downward and upward energy fluxes are equal. If they were not, our planet would gradually heat up or gradually cool down. But the surface of our planet is not simply a mirror for radiation. Some of the incoming ... Full description.

The seasons on Earth are caused by the tilt of the Earth as it rotates on its axis and revolves around the Sun. Students will correlate surface radiation with mean surface temperature of several geographic regions. By observing the graphs of these parameters, students will construct an understanding of the reason for the seasons. Full description.