Interesting...it looks like NIST has _defined_ the acceleration due to gravity to be a certain standard value. This makes sense, as the actual measured value varies slightly according to latitude, altitude, topography, local geology, the time of day (tidal effects), and perhaps even the weather (effects of high and low pressure systems). The precise measurement of g is called "gravimetry." Gravimetry is used by geologists in oil and ore exploration, and a change in measured g may indicate the movement of subterranean magma under a volcano. For example, see http://geology.about.com/library/weekly/aa050999.htm. This "gravimetry" is not to be confused (well, maybe it is,) with the chemistry-type gravimetry, namely the precise measurement of specific gravity.
Vickie Frohne
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From: Forum for Physics Educators on behalf of David Abineri
Sent: Thu 9/23/2004 3:41 PM
To: PHYS-L@LISTS.NAU.EDU
Subject: Standard Gravity
Does anyone what this link refers to when giving an exact value of
standard gravity? I'm not quite sure what this really means?