Lecture History of Sonography

Question 1

550BC sound pitch/frequency relationship

Answer 1

Pythoagorus

Question 2

322-384BC sound propagation

sound carried by movement of AIR

Answer 2

Aristotle

Question 3

480-524AD compared sound waves to pebble in water

Answer 3

BOEthius

Question 4

1500 sound travels waves

>reflection= >incidence

Answer 4

DaVinci

Question 5

1638 sound

frequency determines pitch

Answer 5

Galileo

Question 6

1877 “Theory of Sound”
who wrote it?
contents of book (2)

Answer 6

Lord Rayleigh

• mechanics of vibrating medium=sound production
• acoustic wave propagation

Question 7

what is the range of normal human hearing

Answer 7

20Hz —– 20 kHz

Question 8

Hz

Answer 8

Hertz
SI measurement system
units of frequency
1 cycle per second

Question 9

kHz

Answer 9

killohertz

1000 cycles per second

Question 10

what does ultra stand for in ultrasound?

Answer 10

frequencies above range of human hearing

20 kHz

Question 11

what do bats and dolphins have to do with ultrasound frequencies?

Answer 11

they use it to navigate

Question 12

who discovered the piezoelectric effect?

Answer 12

Curie Brothers 1880

Question 13

what is piezoelectric effect?

Answer 13

crystals expand/contract when placed in an alternating electrical field512+3