The document discusses lasers and their properties compared to ordinary light. It provides details on: 1) Lasers emit light that is highly directional, monochromatic, and coherent, while ordinary light is emitted in many directions and is a combination of wavelengths. 2) Gas lasers work by applying a voltage to excite gas atoms in a tube to produce population inversion and emit continuous wave light. 3) Lasers can pose eye, skin, chemical, electrical, and fire hazards depending on their power level and are classified based on factors like wavelength and output.