Final answer:
An infrared thermometer is best used for measuring surface temperatures, such as those of ventilation systems or for non-contact body temperature readings in the ear, thanks to its ability to detect infrared radiation.
Step-by-step explanation:
An infrared thermometer is best used for measuring surface temperatures. These devices work by detecting infrared radiation, which varies with temperature, to give a temperature readout without requiring contact with the object being measured. This makes them ideal in situations such as measuring the temperature of an aircraft carrier's ventilation system as seen in the example of Fireman Jason Ormand, or for taking body temperature readings with ear thermometers that avoid contact with mucous membranes to reduce the possibility of cross-infection and allow rapid measurement.
Infrared thermometers are not designed to read through glass as glass can reflect or absorb infrared radiation, thus giving inaccurate readings. Likewise, they are not the best choice for verifying internal temperatures since they measure surface temperatures and the internal temperature could be very different. Although they can work in dusty environments to a certain extent, heavy dust could potentially interfere with the accuracy of the infrared readings.