Inch of mercury

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<div class="definition"><div class="short_definition">A common unit used in the measurement of [[atmospheric pressure]].</div><br/> <div class="paragraph">1) One inch of mercury (in Hg) is defined as that [[pressure]] exerted by a 1-in. column of  [[mercury]] at [[standard gravity]] and a [[temperature]] of 0&deg;C:  <div class="display-formula"><blockquote>[[File:ams2001glos-Ie2.gif|link=|center|ams2001glos-Ie2]]</blockquote></div>This is a unit recommended for meteorological use.</div><br/> <div class="paragraph">2) One 45&deg; inch of mercury [in Hg (45&deg;)] is defined as that pressure exerted by a 1-in. column  of mercury at 45&deg; latitude at [[sea level]] and a temperature of 0&deg;C.</div><br/> <div class="paragraph">It is evident that for most purposes these two units are interchangeable. When this is not the  case, the unit should be carefully specified. Metric, rather than the English, units of length are  used in many branches of science, and in other parts of the world. The early development and  continued widespread use of the [[mercury barometer]] has fostered this manner of expressing  atmospheric pressure. Although it has largely been replaced by the [[hectopascal]] (hPa) in most  meteorological work, inches of mercury is still used in [[altimetry]], and it remains the most common  form of [[barometer]] scale [[calibration]].</div><br/> </div>
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<div class="definition"><div class="short_definition">A common unit used in the measurement of [[atmospheric pressure]].</div><br/> <div class="paragraph">1) One inch of mercury (in Hg) is defined as that [[pressure]] exerted by a 1-in. column of  [[mercury]] at [[standard gravity]] and a [[temperature]] of 0&#x000b0;C:  <div class="display-formula"><blockquote>[[File:ams2001glos-Ie2.gif|link=|center|ams2001glos-Ie2]]</blockquote></div>This is a unit recommended for meteorological use.</div><br/> <div class="paragraph">2) One 45&#x000b0; inch of mercury [in Hg (45&#x000b0;)] is defined as that pressure exerted by a 1-in. column  of mercury at 45&#x000b0; latitude at [[sea level]] and a temperature of 0&#x000b0;C.</div><br/> <div class="paragraph">It is evident that for most purposes these two units are interchangeable. When this is not the  case, the unit should be carefully specified. Metric, rather than the English, units of length are  used in many branches of science, and in other parts of the world. The early development and  continued widespread use of the [[mercury barometer]] has fostered this manner of expressing  atmospheric pressure. Although it has largely been replaced by the [[hectopascal]] (hPa) in most  meteorological work, inches of mercury is still used in [[altimetry]], and it remains the most common  form of [[barometer]] scale [[calibration]].</div><br/> </div>
 
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Latest revision as of 17:27, 20 February 2012


[edit] inch of mercury

A common unit used in the measurement of atmospheric pressure.

1) One inch of mercury (in Hg) is defined as that pressure exerted by a 1-in. column of mercury at standard gravity and a temperature of 0°C:
ams2001glos-Ie2
This is a unit recommended for meteorological use.

2) One 45° inch of mercury [in Hg (45°)] is defined as that pressure exerted by a 1-in. column of mercury at 45° latitude at sea level and a temperature of 0°C.

It is evident that for most purposes these two units are interchangeable. When this is not the case, the unit should be carefully specified. Metric, rather than the English, units of length are used in many branches of science, and in other parts of the world. The early development and continued widespread use of the mercury barometer has fostered this manner of expressing atmospheric pressure. Although it has largely been replaced by the hectopascal (hPa) in most meteorological work, inches of mercury is still used in altimetry, and it remains the most common form of barometer scale calibration.

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