Either the Hard Drive spinning or a fan.
Heat is a form of energy, you are adding energy to the system, this causes the particles to vibrate faster.
Mechanical Waves
Thermal energy causes particles to vibrate. When thermal energy is transferred to an object, its particles gain kinetic energy, causing them to move and vibrate.
Sound waves cause the tympanic membrane (eardrum) to vibrate, which in turn causes the malleus (hammer) to vibrate. This vibration is transmitted through the ossicles in the middle ear, ultimately leading to movement of the stapes against the oval window of the cochlea.
When a source of energy causes a medium to vibrate, it creates sound waves. Sound waves are mechanical waves that travel through a medium by causing the particles of the medium to vibrate and transfer energy in the form of sound.
Heat is a form of energy, you are adding energy to the system, this causes the particles to vibrate faster.
Heat!
Heat energy from the source causes the particles to oscillate (vibrate) this chains and causes neighbouring particles to vibrate.
Mechanical Waves
Thermal energy causes particles to vibrate. When thermal energy is transferred to an object, its particles gain kinetic energy, causing them to move and vibrate.
they vibrate..
vibrate or oscillate. This vibration is then transferred through the medium, causing particles in the medium to also vibrate. This transfer of energy produces the mechanical wave.
sound
the vibrations from your lips
sound
Sound waves cause the tympanic membrane (eardrum) to vibrate, which in turn causes the malleus (hammer) to vibrate. This vibration is transmitted through the ossicles in the middle ear, ultimately leading to movement of the stapes against the oval window of the cochlea.
All states of matter have vibrating particles, but solids' particles vibrate only.