7L Sound Flashcards
Making Sounds
Sounds are made by something vibrating.
Intensity
How loud or soft a sound is- its volume.
Pitch
How high or low a sound is.
Frequency
The number of vibrations each second.
The higher the frequency the higher the pitch.
Hertz (Hz)
The units for measuring frequency.
Amplitude
The size of vibrations.
The bigger the amplitude the louder the note.
Humans making Sounds
Two flaps (vocal folds) across the windpipe vibrate when air moves across them.
Vacuum
A completely empty space. Sound cannot travel through.
Sound wave
Formed by the moving vibrations.
Moving sounds
Sounds can only travel through a medium (a solid, liquid or gas).
Sound Moving Through the Air
Air particles vibrate and cause nearby particles to vibrate so the vibrations spread through the air.
Sound wave frequency
The number of waves passing a point per second.
How Ears Detect Sounds
Sound waves enter the ear canal.
the eardrum (a thin membrane) vibrates.
Vibrations pass to the tiny bones which amplify the vibrations.
vibrations pass to the liquid inside the cochlea.
Tiny hairs inside the cochlea detect vibrations and create electrical signals (impulses).
Impulses travel along the auditory nerve to the brain.
Infra-sound
Sounds below 20Hz
Decibels
The units for measuring the loudness of a sound.
