Sonar (SOund Navigation And Ranging)
The use of sound to navigate, communicate with, or detect objects – on or under the surface of the water – such as another vessel.
Active sonar uses a sound transmitter and a receiver.
Active sonar creates a pulse of sound, often called a “ping”, and then listens for reflections (echo) of the pulse.
Several animals developed sonar through evolution by natural selection.
Medical ultrasound – a diagnostic imaging technique using ultrasound.
Used to see internal body structures such as tendons, muscles, joints, vessels and internal organs.
The practice of examining pregnant women using ultrasound is called obstetric ultrasound.
Ultrasound is sound waves with frequencies which are higher than those audible to humans (>20,000 Hz).
Ultrasonic images also known as sonograms are made by sending pulses of ultrasound into tissue using a probe.
The sound echoes off the tissue; with different tissues reflecting varying degrees of sound. These echoes are recorded and displayed as an image to the operator.
“Amniocentesis is a prenatal test in which a small amount of amniotic fluid is removed from the sac surrounding the fetus for testing. The sample of amniotic fluid (less than one ounce) is removed through a fine needle inserted into the uterus through the abdomen, under ultrasound guidance.”
“The fluid is then sent to a laboratory for analysis. Different tests can be performed on a sample of amniotic fluid, depending on the genetic risk and indication for the test.”