Ultrasound and its applications

Sound is something we encounter every day, but there is a fascinating world of sound that we cannot hear with our ears—such as ultrasound. Ultrasound consists of sound waves with a frequency higher than the upper limit of human hearing. While humans can hear sounds in the range of about 20 Hz to 20,000 Hz, ultrasound begins above this range.

Understanding sound waves

Before we learn about ultrasound in detail, let us understand what sound waves are. Sound is a type of energy produced by vibrations. When an object vibrates, it sends out waves of pressure that travel through air, water or solids. Our ears detect these pressure waves and interpret them as sound.

Sound waves can be represented as transverse waves in diagrams, although they are actually longitudinal waves. Sound waves travel at different speeds in different materials. In air, sound travels at about 343 metres per second (1235 km/h).

What is ultrasound?

Ultrasound refers to sound waves with a frequency above 20,000 Hz, which is beyond the upper limit of human hearing. These high-frequency sound waves can travel through a variety of materials, including air, water, and body tissue.

Frequency of sound waves

Frequencies are measured in hertz (Hz), and they tell us how many waves pass a certain point in one second. Here's a simple formula to help you understand frequency:

Frequency (f) = Number of waves/Time (in seconds)

Ultrasound typically operates at frequencies ranging from 1 million hertz (1 megahertz) to 10 billion hertz (10 GHz). As a result, these waves can do things that normal sound waves cannot do because of their higher frequency.

Applications of ultrasound

Ultrasound has many applications due to its unique properties. Let's take a look at some of the most common uses.

Medical imaging

In medicine, ultrasound technology is widely used for imaging. It helps doctors see inside the human body without the need for surgery. This type of ultrasound uses a device called a transducer. The transducer emits ultrasound waves, which bounce off tissues in the body and return to the transducer. These returning echoes are converted into visible images.

Example: Prenatal ultrasound scan

Prenatal ultrasound scans are a common medical use of ultrasound. They allow doctors to see the fetus developing in the womb and make sure it is growing correctly. Parents also have the opportunity to see pictures of their baby before birth.

Industrial applications

Ultrasound is used not only in medicine but also in industry. It can be used for non-destructive testing of materials. This means that it can test the integrity of materials without causing any damage.

Example: Detecting cracks in metal

Ultrasound can be used to detect cracks in large metal structures such as bridges or aircraft. A device such as a medical transducer sends ultrasound waves through the metal. If there is a crack, the waves will reflect differently, indicating a problem.

Cleaning delicate items

Another industrial use of ultrasound is cleaning. Ultrasonic cleaners use high-frequency sound waves to create tiny bubbles in liquids. These bubbles move around and help remove dirt and grime from delicate items such as jewelry and small machine parts.

Example: Jewelry cleaning

A typical ultrasonic cleaner places the ring or necklace in a solution and exposes them to ultrasound waves. The tiny bubbles produced by these waves gently clean the fine parts of the jewellery.

The science behind ultrasound

The ability of ultrasound waves to interact with different materials is what makes these applications possible. To understand how these waves work, it is important to look at the properties of the waves.

Reflection

Just as a mirror reflects light, some surfaces can reflect sound waves. When ultrasound waves hit a surface, they bounce back. This is called reflection. In medical ultrasound, reflections from different tissue types create images.

Refraction

Refraction occurs when waves pass through different mediums, changing their speed and direction. This can also happen with ultrasound, causing images to become slightly distorted.

Attenuation

As sound waves travel through a medium, they can lose energy, a process called attenuation. Different materials attenuate sound waves to different degrees. This is why some images in ultrasound appear sharper than others, depending on the density of the tissue.

Towards the future

The potential of ultrasound technology is constantly growing. Researchers are exploring new uses, such as advanced medical treatments and advanced cleaning techniques. With continued advancements, ultrasound is expected to play an important role in both the medical and industrial fields.

Example: New medical treatments

Future research is looking into using ultrasound for targeted drug delivery. By focusing ultrasound waves on a specific area in the body, it is possible to target drugs to precise locations, minimising side effects.

Summary

Ultrasound offers unique advantages due to its high frequency and non-invasive nature. Its applications range from important medical diagnostics to innovative industrial solutions. Understanding how it works helps us understand how sound interacts with different materials and how it reaches areas where human hearing cannot reach.

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