🔍 Key Concepts

• Relative humidity – what it measures and why temperature matters • How a psychrometric chart is used (it needs specific inputs like temperatures) • Different meteorological instruments and what each one measures (humidity vs pressure vs density)

💭 Think About

• Ask yourself: what two temperature readings are typically used together to find relative humidity on a psychrometric chart? • Which of these devices is specifically designed to give you those two temperature readings? • Which instruments in the list are mainly used for pressure or liquid density, not air moisture content?

✅ Before You Answer

• Identify which option measures air temperature (often two temperatures at once) rather than pressure or density • Eliminate any instrument that is clearly a barometer (used for atmospheric pressure) • Confirm which device’s name is closely related to the word psychrometric/psychrometer used in the question