Neotropical cloud forests to lose what most defines them: clouds

In as few as 25 years, climate change could shrink and dry 60-80% of Western Hemisphere cloud forests, finds a study published today. If greenhouse gas emissions continue increasing as they have been, 90% of Western Hemisphere ...

New cellulose-based material represents three sensors in one

Cellulose soaked in a carefully designed polymer mixture acts as a sensor to measure pressure, temperature and humidity at the same time. The measurements are completely independent of each other. The ability to measure pressure, ...

Spider silk could be used as robotic muscle

Spider silk, already known as one of the strongest materials for its weight, turns out to have another unusual property that might lead to new kinds of artificial muscles or robotic actuators, researchers have found.

Snowflakes are not as unique as you think

The delicate snow flurries that you watch fall from your window, shovel off your sidewalk, and curse when they turn into slush puddles, have quite a long adventure before they make it to the ground. A snowflake begins its ...

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Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture, called the Absolute humidity. In everyday usage, it commonly refers to relative humidity, expressed as a percent in weather forecasts and on household humidistats; it is so called because it measures the current absolute humidity relative to the maximum. Specific humidity is a ratio of the water vapor content of the mixture to the total air content (on a mass basis). The water vapor content of the mixture can be measured either as mass per volume or as a partial pressure, depending on the usage.

In meteorology, humidity indicates the likelihood of precipitation, dew, or fog. High relative humidity reduces the effectiveness of sweating in cooling the body by reducing the rate of evaporation of moisture from the skin. This effect is calculated in a heat index table, used during summer weather.

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