Editing Stethoscope (section)

===Acoustic===
[[File:Stethoscope.svg|thumb|Parts of a binaural stethoscope]]
[[Image:Stethoscope pink.JPG|thumb|150px|right|Acoustic stethoscope, with the ''bell'' upwards]]

Acoustic stethoscopes operate on the transmission of sound from the chest piece, via air-filled hollow tubes, to the listener's ears. The chestpiece usually consists of two sides that can be placed against the patient for sensing sound: a diaphragm (plastic disc) or bell (hollow cup). If the diaphragm is placed on the patient, body sounds vibrate the diaphragm, creating acoustic pressure waves which travel up the tubing to the listener's ears. If the bell is placed on the patient, the vibrations of the skin directly produce acoustic pressure waves traveling up to the listener's ears. The bell transmits low frequency sounds, while the diaphragm transmits higher frequency sounds. To deliver the acoustic energy primarily to either the bell or diaphragm, the tube connecting into the chamber between bell and diaphragm is open on only one side and can rotate.  The opening is visible when connected into the bell. Rotating the tube 180 degrees in the head connects it to the diaphragm. This two-sided stethoscope was invented by Rappaport and Sprague in the early part of the 20th century.{{citation needed|date=June 2019}}