Earth and space science in the middle school classroom are composed of intricately intertwined sets of conceptual systems (AAAS 1993; NRC 1996). Some systems of study, such as the water and rock cycles, are quite explicit and often found as stand-alone middle school science units. Other phenomena are not so apparent, yet they play an extremely important role when studying many crosscutting concepts associated with Earth systems. The albedo effect is a basic concept that can help students understand the connected relationships among the hydrosphere, atmosphere, lithosphere, biosphere, and cryosphere. By the end of this lesson, middle school students will gain a better understanding of the following: (1) Planet Earth intercepts solar energy from the Sun; (2) Energy from the Sun is reflected and absorbed by the Earth; (3) Places on Earth react differently when exposed to solar radiation; and (4) Albedo helps determine how energy transfers from the Sun to the Earth. (Contains 9 figures and 3 online resources.)