Ultrasound

• What is the frequency range that defines ultrasound?

  Ultrasound is defined as sound vibrating at frequencies above 20,000 Hertz.
• Which animals naturally produce ultrasound and for what purposes?

  Bats naturally produce ultrasound for communication and echolocation.
• How do humans produce ultrasound?

  Humans produce ultrasound using electrical devices that convert electrical oscillations into sound waves.
• What happens when ultrasound hits a boundary between two different mediums?

  Some waves are reflected off the boundary while others are transmitted through and refracted.
• What is the process called when only some ultrasound waves are reflected at a boundary?

  This process is called partial reflection.
• How can we determine the distance to a boundary using ultrasound?

  By knowing the speed of sound and the time it takes for the waves to be reflected, we can calculate the distance.
• What can we learn about an object by analyzing reflected ultrasound waves?

  We can learn about the different boundaries within the object, which tells us about its internal structure.
• Is ultrasound safe for use in medical imaging?

  Yes, ultrasound is completely safe and does not involve radiation.
• What is a common application of ultrasound in medicine?

  Ultrasound is commonly used in prenatal scanning to check the health of fetuses.
• How does ultrasound work in prenatal scanning?

  An ultrasound device transmits and receives sound waves that reflect off the fetus to create a live image.
• What happens to ultrasound waves when they pass from one medium to another during prenatal scanning?

  Some waves are reflected back to the device, and the timings and distributions of these echoes are processed to produce an image.
• How is ultrasound used in industrial imaging?

  Ultrasound checks the quality of products by detecting cracks through reflected waves.
• What indicates a fault in an object during industrial ultrasound testing?

  If reflected waves are detected unexpectedly, it indicates a crack or fault in the object.
• What is echo sounding or sonar used for?

  Echo sounding or sonar is used by boats to sense submarines and other objects in the ocean.
• How does a submarine use ultrasound to determine the distance to the seafloor?

  The submarine fires a pulse of ultrasound and measures the time it takes for the reflected waves to return.
• If a submarine detects reflected waves six seconds after firing ultrasound at a speed of 1400 meters per second, what is the distance to the seafloor?

  The distance to the seafloor is 4,200 meters.
• Why is the distance calculated from the submarine to the seafloor only half of the total distance traveled by the ultrasound waves?

  Because the time measured includes the journey to the seafloor and back, so we divide by two to find the one-way distance.
• What are the main applications of ultrasound technology?

  • Prenatal scanning to check fetal health
  • Industrial imaging to detect product quality
  • Echo sounding or sonar for navigation and object detection in water