How ultrasound and infrasound differ from normal sound?

Ultrasound

Ultrasound refers to sound waves with frequencies higher than the upper limit of human hearing, which is generally considered to be around 20,000 Hz. These waves are inaudible to humans but are commonly used in various applications such as medical imaging (sonography), industrial cleaning, and non-destructive testing. Some animals, like bats and dolphins, can hear and use ultrasound for echolocation and communication.

Key characteristics of ultrasound:

1. High Frequency: The frequency range of ultrasound is typically between 20,000 Hz and several gigahertz (GHz).

2. Short Wavelength: Due to their high frequency, ultrasound waves have short wavelengths, allowing for precise focusing and imaging.

3. Inaudible: Humans cannot hear ultrasound sounds because their ears are not sensitive to frequencies above the audible range.

Applications of ultrasound:

1. Medical Imaging: Ultrasound is widely used in medical diagnostics for obtaining images of internal organs and structures. It is safe and painless, using high-frequency sound waves to create real-time images.

2. Industrial Cleaning: Ultrasonic waves can generate high-frequency vibrations in cleaning solutions, effectively removing dirt and impurities from surfaces.

3. Non-destructive Testing: Ultrasound can detect defects, cracks, or flaws in materials without damaging the object being inspected.

Infrasound

Infrasound refers to sound waves with frequencies below the lower limit of human hearing, which is generally considered to be around 20 Hz. These waves are too low-pitched for human perception and are often associated with natural phenomena such as earthquakes, volcanic eruptions, and certain animal vocalizations.

Key characteristics of infrasound:

1. Low Frequency: Infrasound waves have frequencies below 20 Hz, extending down to extremely low frequencies.

2. Long Wavelength: Due to their low frequency, infrasound waves have long wavelengths, making them difficult to detect and study.

3. Sub-audible: Infrasound sounds cannot be heard by humans because they are below the range of human auditory perception.

Sources of infrasound:

1. Natural Phenomena: Infrasound can originate from natural events such as volcanic activity, earthquakes, wind turbulence, and ocean waves.

2. Industrial Processes: Certain industrial activities like machinery, wind turbines, and large engines can generate infrasound.

Applications of infrasound:

1. Earthquake Monitoring: Infrasound sensors can detect and monitor seismic activity, providing valuable data for earthquake early warning systems.

2. Atmospheric Research: Infrasound waves can be used to study atmospheric conditions, temperature variations, and weather phenomena.

3. Animal Communication: Some animals, such as elephants, whales, and certain insects, use infrasound for long-distance communication and social interactions.