Sound Waves and Ultrasound Flashcards

Flashcards about Sound Waves and Ultrasound

Sound waves

Produced by vibrating sources and require a medium to travel through because they are longitudinal waves.

Longitudinal waves

Waves in which the vibration is parallel to the direction of energy transfer; consist of compressions and rarefactions.

Compression

A region in a longitudinal wave where the density is higher and molecules are bunched together.

Rarefaction

A region in a longitudinal wave where the density is lower and molecules are spread out.

Speed of sound in air

Varies from 330-350 m/s; increases with higher air temperature.

Speed of sound in different mediums

Travels fastest in solids (around 5000 m/s), slower in liquids (around 1500 m/s), and slowest in gases (around 330-350 m/s).

Trundle Wheel

Equipment with the purpose to measure the distance travelled by sound waves.

Wooden Blocks

Equipment with the purpose to create a sound when banged together.

Oscilloscope

Equipment with the purpose to display the sound wave electronically.

Echo

The reflection of a sound wave off a hard surface.

Frequency and Pitch

A high pitch has a high frequency (or short wavelength), while a low pitch has a low frequency (or long wavelength).

Amplitude and Volume

A large amplitude has a high volume, while a small amplitude has a low volume.

Human Hearing Range

Approximately 20 Hz to 20,000 Hz; Decreases with age.

Ultrasound

Sound with a frequency higher than 20 kHz.

Uses of ultrasound

Includes non-destructive testing of materials, medical scanning of soft tissue, and sonar to calculate depth or distance.

Ultrasound transducers

Equipment with the purpose to emit and receive ultrasound signals, and display the received signal on an oscilloscope screen.

Calculating depth of a boundary with ultrasound

depth = 1/2 × speed × time, where 'time' is the total time from ultrasound emission to receipt.

Applications of ultrasound in industry

Checking for cracks inside metal objects and generating images from beneath surfaces.

Applications of ultrasound in medicine

Constructing images of a foetus in the womb, generating images of organs, and medical treatments like removing kidney stones.

Sonar

A system that uses echo sounding to measure depth or detect objects underwater.

Echo sounding

Used to determine water depth; the time it takes for a sound wave to return after being reflected off the ocean floor is used to calculate the depth.