5.6 - Ultrasound

• What is the frequency range of ultrasound?

  Above 20,000 Hertz
• How do humans produce ultrasound?

  Using electrical devices
• What happens when ultrasound hits a boundary between two mediums?

  Some waves are reflected, some transmitted
• What is the process called when only some ultrasound waves are reflected?

  Partial reflection
• How can we determine the distance to a boundary using ultrasound?

  By knowing speed and reflection time
• Why is ultrasound considered safe?

  It does not involve radiation
• Ultrasound is:

  Sound with frequencies above human hearing (above 20,000 Hz)
• What is a common use of ultrasound in medicine?

  Scanning fetuses
• How does an ultrasound device work in prenatal scanning?

  It transmits and receives sound waves
• What happens to ultrasound waves when they pass from tissue to fluid?

  Some waves are reflected back
• How are the reflected waves processed in prenatal scanning?

  By a computer to produce images
• What is the purpose of using ultrasound in industrial imaging?

  To check the quality of products
• What indicates a fault in an object during industrial ultrasound testing?

  Unexpected reflected waves
• What is echo sounding also known as?

  Sonar
• How do submarines use ultrasound?

  To detect objects in the ocean
• If ultrasound travels at $1400 \text{ m/s}$ and takes $6 \text{ seconds}$ to return, what is the total distance traveled?


  $8400 \text{ meters}$
• Why do we divide the total distance by two in sonar calculations?

  To account for the return trip
• What is the distance from the submarine to the seafloor if the total distance is $8400 \text{ meters}$?


  $4200 \text{ meters}$
• What are the main applications of ultrasound technology?

  • Prenatal scanning
  • Industrial imaging
  • Sonar for underwater detection
• What are the key processes involved in ultrasound imaging?

  1. Sound wave generation
  2. Wave reflection and transmission
  3. Echo processing to create images
• Bats naturally produce ultrasound for:

  • Echolocation
  • Communication
• Ultrasound can be produced using a:

  Speaker
• Ultrasound is:

  Safe
• The time taken for ultrasound to bounce back to the receiver can be used to calculate the thickness of the medium.

  
• Ultrasound can be used to check for cracks in solid products. The ultrasound would reflect off of the crack and be detected.
• Ultrasound can be used to check for cracks in solid products. The ultrasound would reflect off of the crack and be detected.

  
• ltrasound is used as sonar by boats and submarines. By reflecting the ultrasound off the sea floor, we can calculate the distance from the sea floor.