Watercress is fun and easy to grow at home. Take a look at our article showing you how to use the grocery store watercress to start your own patch of watercress at home. Hydroponic Water Cress. This is an image of commercially hydroponically grown watercress.
Fog is the extreme of humidity. Humidity control systems add or remove water vapor from indoor air to stay within proper humidity ranges. Humidity control is important for three reasons: 1  It is a large factor in people's thermal comfort.2  Excess moisture in a building can lead to mold and mildew, causing problems for indoor air quality.umidity control systems add or remove water vapor from indoor air to stay within proper humidity ranges. Humidity control is important for three reasons: 1  It is a large factor in people's thermal comfort.
Higher temperatures make higher levels of humidity possible. This is because warm air is capable of holding more moisture than cold air. Warm air has a stronger bond to water molecules, making the air feel drier and allowing more water to bond with air. In weather forecasting, humidity that is expressed as a percentage is called relative humidity. Relative humidity measures how much of the air's current moisture capacity is used. A relative humidity of 50 percent means that the air holds 50 percent of the moisture possible at the current temperature. This percentage changes with temperature, since colder air holds less moisture. A relative humidity of 100 percent means that the air is completely saturated with moisture.