🔍 Key Concepts

• Sling psychrometer operation – it uses two thermometers: a dry bulb and a wet bulb • Effect of evaporation – why the wet bulb usually reads lower than the dry bulb • Standard meteorological term for the temperature difference between dry and wet bulb readings

💭 Think About

• Ask yourself: What exactly is being measured when you take the dry bulb reading and subtract the wet bulb reading? Is it a temperature, a percentage, or a kind of difference? • Think about dew point: Is dew point a single temperature value or the difference between two temperatures? • Consider what meteorologists call the gap between dry bulb and wet bulb temperatures when they use psychrometric charts to find relative humidity.

✅ Before You Answer

• Verify which option is specifically defined as the difference (dry bulb minus wet bulb), not the humidity itself. • Confirm that relative humidity is expressed as a percentage, not as a temperature difference in degrees. • Check that dew point is a particular temperature at which condensation begins, not a spread between two thermometer readings.