Emission spectra are patterns of light emitted by atoms or molecules when they transition from a higher energy state to a lower one. When energy is supplied, such as through heat or electricity, electrons in the atoms become excited and jump to higher energy levels. As they return to their original levels, they release energy in the form of light. Each element has a unique emission spectrum, which appears as a series of bright lines at specific wavelengths. This characteristic pattern allows scientists to identify elements in various substances, making spectroscopy a valuable tool in fields like astronomy and chemistry.