Sound | Notes

How does sound energy travel?

Travels in the form of sound waves

There are 2 types of sound waves - transverse and longitudinal waves


Transverse Waves

Particles vibrate perpendicular to the wave

This is light


Longitudinal Waves

The vibration of the particles are parallel to the wave

Sound waves are longitudinal waves

These waves can go through solids, liquids, and gasses. It travels the fastest through solids, slower in liquids, or slowest in gasses. This is because solids are denser than liquids and liquids are denser than gasses


Sound travels in all directions. It bounces off of solids. When it hits your ears again, its called echo.

Sonar - used to detect depth of the seabed

Echolocation - usualy used for animals that use sounds to detect location.

Echolocation and sonar is VERY simmilar.


The nature of waves

A wave is a traveling disturbance

Waves carry energy from place to place

Periodic waves are waves that repeat

Frequency is the number of waves per unit time | f=1/T


The Frequency of a Sound Wave

Audible Range: 20Hz---20,000Hz

Infrasonic waves: Sound waves with frequencies < 20Hz

---Rhinoceroses use infrasonic frequencies as low as 5Hz to call one another

Ultrasonic Waves: Sound waves with frequencies > 20,000Hz

---Bats use ultrasonic frequencies up to 100kHz for locating their food sources and navigating


Diffraction

Diffraction is the bending of a wave around an obstacle or the edges of an opening


The Doppler Effect

Effect on frequency or pitch due to relative motion between the source of sound and the observer/listener