“How can we measure the amount of humidity in a system?”
If you have ever traveled to moist locations such as India or the East Coast of the United States, then you will learn very quickly of something called humidity. This feature of air can make it feel like you are swimming in a sauna. However, have you ever wondered how can we measure this phenomenon? Well, we know that the more water is contained within a local atmosphere, the more humidity is experienced. And we also know that the total amount of pressure within water vapor at this temperature will be unable to exceed the equilibrium vapor pressure of the water (because if it did, it would just sink right back into the water!). So what if we were to take the ratios of these values for an area? Well, this value is known as the relative humidity and is used in vital for weather forecasts and HVAC system control.