What is relative humidity?

What is relative humidity?

• A. The percentage of water that air can hold
• B. The amount of water inside a cage
• C. The humidity level required for an animal to thrive
• D. The temperature at which air is completely saturated with moisture

Answer: (A)

Relative humidity describes how full the air is with water vapor compared to how much it could hold at the current temperature. It’s a percentage: if the air is warmer, it can hold more moisture, so the same amount of water vapor might give a different relative humidity than it would at a cooler temperature. This concept helps explain why air can feel humid on a warm day even if there isn’t a huge amount of water in the air, or why cooler air with the same water vapor content feels drier. The other ideas don’t fit as well. It’s not simply the amount of water inside a cage, nor a fixed humidity level needed for a particular animal (that depends on species and context). And it’s not the temperature at which air becomes completely saturated—that temperature is the dew point, not a humidity percentage.

Relative humidity describes how full the air is with water vapor compared to how much it could hold at the current temperature. It’s a percentage: if the air is warmer, it can hold more moisture, so the same amount of water vapor might give a different relative humidity than it would at a cooler temperature. This concept helps explain why air can feel humid on a warm day even if there isn’t a huge amount of water in the air, or why cooler air with the same water vapor content feels drier.

The other ideas don’t fit as well. It’s not simply the amount of water inside a cage, nor a fixed humidity level needed for a particular animal (that depends on species and context). And it’s not the temperature at which air becomes completely saturated—that temperature is the dew point, not a humidity percentage.