The physical mechanisms that may cause a temperature probe to indicate a temperature different from that intended include conduction, radiation, snd velocity recovery errors. In any real measurement system, their effects coupled, and therefore should not be considered independently. However, for simplicity, we will consider each separately because out pupose is to provide only estimates of the error, and not to provide predictive techniquses for correcting measured temperatures. The goal of the measurement engineer should be to minimize these errors, as far as possible, throngh the careful installation and design of temperature probes.