Most likely, solar cells will play a significant role in this country's strategy to address the two interrelated issues of global warming and dependence on imported oil. The purpose of this paper is to present an explanation of how solar cells work at an introductory high school, college, or university physics course level. The treatment presented here will be qualitative and somewhat simplified, in order to reach the desired audience; references are provided for a more detailed and mathematically sophisticated treatment. It is hoped that this paper will, in a small way, motivate students to learn more about this technology, so critical to the energy and environmental future of this country.