Greek mathematician who observed the relationship between sound pitch and frequency. He discovered the sonometer.
Christian Johann Doppler
Austrian scientist who studied the effect of motion on the pitch of sound. Called the Doppler effect.
Helped develop the metal flaw detectors and naval sonar.
Credited with perfecting the A-mode measurement of the fetal biparietial diameter making it possible to ultrasonically estimate fetal age, weight, and growth rate. Known as the "father of obstetrical ultrasound".
Archytas of Tarentum
400 BC. Greek scholar, defined nature of sound. Sound is produced by the motion of one object striking another ... fast motion = high pitch ... slow motion = low pitch
350 BC. Greek Philosopher and Scientist. Therory of Sound Propagation. Sound is carriewd to the ears by the movement of air.
Roman Philosopher. First to compare sound wavws to the waves produced by dropping a pebble into a cal body of water. This theory is still used today.
Leonardo Da Vinci
1500 AD. (Post renaissance period). Study of the physical properties of sound. Originated the idea that sound travels in waves. Credited with discovery that angle of reflection = angle of incidence.
1638. Frequency of sound waves determines pitch.
Sir Isaac Neewton
Late 1600's. Derivation of the theory of velocity.
Late 1600's. English Chemist. Popularized the theory of elasticity of air.
1877. British scientist. THEORY OF SOUND published - marked the beginning of the modern study of acoustics.
1793. Italian Priest / Scientist. Studied activities of bats. Observation: bats could function if blinded in the dark, but not if deafened.... Theorized: bats were listening to something he could not hear - what it was he didn't know.
1938. Inveneted a sonic detector - pick up high frequency vibrations of bats and to convert them into audible sounds.
1942. Austrian became the first physician to use ultrasound for diagnostic purposes ... used to detect brain tumors.
1947-1949. First used ultrasound to detect gallstones at MIT. A-Mode.