How Stuff Works explains that sound travels in mechanical waves, and these waves are disturbances that cause energy to move. The energy is then transported through a medium. Disturbances occur when an object vibrates. This vibration is caused by interconnected and interactive particles.
Sound has the ability to travel through gases, liquids and solids. How Stuff Works sates that the speed of any sound wave is highly dependent on the medium through which it travels. The speed of sound is greater when it travels through solids. It travels more slowly when it goes through liquids and gases. This means that the denser the medium through which sound travels, then the slower it passes. This is evidenced by the fact that sound travels faster on a warm day than on a cold day.
The sounds that one hears are created when air particles collide. These air particles pass from the object the sound is coming from into the eardrum, which is also known as the tympanic membrane. This movement of sound waves from the object to one's eardrums is called transmission. How Stuff Works explains that when the air particles collide with the eardrum, vibrations resonate through several different structures in the ear: These vibrations are sent as messages to the brain, where they are interpreted as sound.