P12.6 The uses of ultrasound

Question 1

What are ultrasound waves?

Answer 1

Waves above the highest frequency that humans can detect are called ultrasound waves

Question 2

What are ultrasound waves used for?

Answer 2

For prenatal scans of a baby in the womb

To get images of organs in the body such as kidney or damaged ligaments and muscles

Question 3

What is the role of a transducer?

Answer 3

Produces and detects set(or pulses) of ultrasound waves

Question 4

How does the ultrasound wave pulse travel from the transducer?

Answer 4

It is partially reflected from the different tissue boundaries in its path
Returns to the transducer as a sequence of ultrasound waves reflected by the tissue boundaries - arriving back at different times

Question 5

What is the purpose moving the transducer?

Answer 5

The ultrasound waves are then detected by the transducer

Used tip build up an image on a screen of the internal tissue boundaries in the body

Question 6

What are the advantages of using ultrasound waves?

Answer 6

They are reflected at boundaries between different types of tissue (different media) so they can be used to scan organs and other soft tissues in the body

They are non-ionising. Non-ionising radiation is radiation that does not have enough energy to remove an electron to ionise an atom or molecule - so it is harmless when used for scanning

Question 7

How can fatal flaws in metal casting be found using ultrasound waves?

Answer 7

A flaw might be an internal crack that creates a boundary inside the metal
The ultrasound waves are partly reflected from this boundary
The transducer at the surface of the block sends ultrasound waves into the block. The reflected waves are detected by the transducer and displayed on an oscilloscope screen

Question 8

Why is there a strong ultrasound wave pulse?

Answer 8

Due to partial reflection of the transmitted pulse at the surface