Search results
Results from the WOW.Com Content Network
A hygrometer is an instrument which measures the humidity of air or some other gas: that is, how much of it is water vapor. [1] Humidity measurement instruments usually rely on measurements of some other quantities, such as temperature, pressure, mass, and mechanical or electrical changes in a substance as moisture is absorbed.
This corresponds to 751.16 mm, [9] so that on the present-day definition, this boiling point is 99.67 degrees Celsius. [10] 1743 — Jean-Pierre Christin had worked independently of Celsius and developed a scale where zero represented the melting point of ice and 100 represented the boiling point but did not specify a pressure. [8]
The accuracy of a simple wet-bulb thermometer depends on how fast air passes over the bulb and how well the thermometer is shielded from the radiant temperature of its surroundings. Speeds up to 5,000 ft/min (~60 mph, 25.4 m/s) are best but it may be dangerous to move a thermometer at that speed.
Hygrometer for measuring humidity; Anemometer for measuring wind speed; Pyranometer for measuring solar radiation; Rain gauge for measuring liquid precipitation over a set period of time; Wind sock for measuring general wind speed and wind direction; Wind vane (also called a weather vane or a weathercock) for showing the wind direction
The wet-bulb temperature is the lowest temperature that may be achieved by evaporative cooling of a water-wetted, ventilated surface.. By contrast, the dew point is the temperature to which the ambient air must be cooled to reach 100% relative humidity assuming there is no further evaporation into the air; it is the temperature where condensation (dew) and clouds would form.
A hygrometer measures the relative humidity at a location, which can then be used to compute the dew point. Radiosondes directly measure most of these quantities, except for wind, which is determined by tracking the radiosonde signal with an antenna or theodolite .
Created Date: 8/30/2012 4:52:52 PM
The word hygroscopy (/ h aɪ ˈ ɡ r ɒ s k ə p i /) uses combining forms of hygro-(for moisture or humidity) and -scopy. Unlike any other -scopy word, it no longer refers to a viewing or imaging mode. It did begin that way, with the word hygroscope referring in the 1790s to measuring devices for humidity level. These hygroscopes used ...