This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 Excerpt: ...Light House Bureau. Henry noted that the sound of a steam siren at A often passed completely above a vessel at B but could be heard distinctly at a second vessel stationed at C. Refraction of this sort is caused apparently by successive layers of air having different densities, due to differences in temperature. ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 Excerpt: ...Light House Bureau. Henry noted that the sound of a steam siren at A often passed completely above a vessel at B but could be heard distinctly at a second vessel stationed at C. Refraction of this sort is caused apparently by successive layers of air having different densities, due to differences in temperature. Loudness And Intensity Of Sound 277. Distinction between Loudness and Intensity. Loudness is a term used to designate the strength of the sensation received through the medium of the ear. The loudness with which a given sound is heard depends in part on the energy of the vibrating system and in part on the nature of the hearing mechanism of the individual. It is probable that no two persons hear the same sound with exactly the same degree of loudness; indeed, the loudness with which a given individual perceives a sound varies from time to time, depending upon the state of health and nervous condition. Intensity of sound is a physical characteristic quite independent of the hearing mechanism. Intensity may be defined as the quantity of energy in the sound wave passing through a surface of unit area (1 cm2) in one second. It is understood that the unit area is at right angles to the direction of propagation of the sound wave. Intensity, being a physical quantity, can be measured. Loudness, on the other hand, cannot be measured in physical units. Loudness is not a physical quantity; it is a sensation. We may say, however, that within certain limits loudness is proportional to intensity. Intensity of sound depends upon several factors as follows: (a) distance from its origin; (b) amplitude of vibration; (c) frequency of vibration; (d) density of the medium; (e) area of the vibrating body. 278. Relation of Intensity to Distance. It is a common experience...
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Add this copy of Physics in Everyday Life to cart. $21.69, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2010 by Nabu Press.
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