Machinery Mate Test 1 Practice 2026 – Complete Exam Preparation

When the dry-bulb and wet-bulb temperatures are the same, the air is saturated with moisture, meaning relative humidity is 100%. The wet-bulb thermometer cools only by evaporation from its wick; if the air cannot take on any more moisture, evaporation stops and the wet-bulb temperature cannot fall below the dry-bulb temperature. So they equalize. This also implies dew point equals the ambient air temperature. If the air were dry, the wet-bulb would be noticeably lower than the dry-bulb due to evaporative cooling, and evaporation would occur more readily.