This concept module on radiation is one of thirteen modules that provide a flexible, laboratory-based physics instructional package designed to meet the specialized needs of students in two-year, postsecondary technical schools. Each of the thirteen concept modules discusses a single physics concept and how it is applied to each energy system. This module addresses mainly the topic of electromagnetic radiation. Included with the concept module are twenty-two application modules that discuss a specific application of a single concept in a single energy system, and contain a student laboratory exercise. Laboratory modules included are Inverse Square Law: Spreading of Light; The Optical Spectrum; Light Sources; Lasers; Stroboscopes: Pulses of Light; Optical Filters: Absorption of Light; Specular and Diffuse Reflection of Light; Image Formation with Mirrors; Prisms: Refraction and Dispersion of Light; Lenses: Focusing and Spreading of Light; Interference: Testing Flat Surfaces; Diffraction Grating: Measuring the Wavelengths of Light; Polarization: Glare Reduction; Holography: Three Dimensional Photography; Spectroscopy: Light Analysis; Infrared Radiation Thermometers; Illumination; Single Lens Reflex Camera; Geiger Counters; Penetrating Power of Alpha and Beta Radiation; Radioactivity; and Absorption of Gamma Radiation. (LRA)