What is Altimeter?
[[File:Aircraft altimeter.JPG|thumb|Altimeter in an aircraft.]] An '''altimeter''' is an [[tool]] that can measure the height of an object, above a reference plane. A common reference plane is [[Sea level|meters above sea level]]. There are different ways that this measurement can be done. The most common one uses [[atmospheric pressure]]. Other ways include [[Ultrasound|ultra sound]], [[laser]] light, or [[Microwave|microwaves]]. Altimeters in planes often use lasers or microwaves.<ref>A Dictionary of Aviation, David W. Wragg. {{ISBN|9780850451634}}, 1st Edition Published by Osprey, 1973 / Published by Frederick Fell, Inc., NY, 1974 (1st American Edition.)</ref> ==References== {{reflist}} [[Category:Measuring tools]]