🔍 Key Concepts

• Dry bulb temperature is the ordinary air temperature measured by a regular thermometer. • Wet bulb temperature is affected by evaporation; the more evaporation, the cooler it reads compared to dry bulb. • On a psychrometric chart, when air is fully saturated, the relative humidity is 100% and certain lines coincide.

💭 Think About

• On the chart, look for where the wet bulb temperature line and the dew point/ grains-of-moisture line intersect the dry bulb temperature axis at the same point. What does the relative humidity read there? • If no evaporation can occur from the wet bulb, how will its temperature compare to the dry bulb? What does that say about the moisture content of the air? • Think about what dew point means: it is the temperature at which condensation begins. If the dew point equals the current air temperature, what does that imply about how much more moisture the air can hold?

✅ Before You Answer

• On the chart, verify what the relative humidity percentage is where the wet bulb, dry bulb, and dew point temperatures coincide. • Confirm whether grains of moisture per pound of dry air is zero or at some positive value at that same condition. • Ensure the chosen option matches the idea that at this condition, the air cannot hold any more water vapor without condensing it.