How do matter and light interact? This lecture is the first of two that will explore the interaction between light and ordinary matter, and how we measure that with spectroscopy. This lecture introduces the idea of internal energy as quantified by the temperature on the Absolute Kelvin scale, and Kirchoff's empirical Laws of Spectroscopy. We will deal primarily with blackbody spectra emitted by hot solids or hot dense gasses or liquids, the Stefan-Boltzmann and Wien Laws, and introduce emission and absorption line spectra. The next lecture will explain how line spectra arise from atoms and molecules. Recorded 2007 Oct 24 in 1000 McPherson Lab on the Columbus campus of The Ohio State University.