Sound, amazing facts. Did you know?
Sound is a mechanical energy wave created by vibrations that travel through a medium (solid, liquid, or gas) by causing molecules to bump into one another. It cannot travel through a vacuum, such as outer space, because there is no matter to propagate the vibrations.
Speed and Medium: Sound travels at approximately 767 mph (343 m/s) in dry air at room temperature, but moves significantly faster in denser materials like water (**~1,482 m/s**) and steel (**~4,512 m/s**). The speed of sound also increases with temperature and depends on the stiffness of the medium.
Properties and Perception: Sound waves are characterized by frequency (measured in Hertz, Hz), which determines pitch, and amplitude (measured in decibels, dB), which determines loudness. Humans can typically hear frequencies between 20 Hz and 20,000 Hz; sounds below 20 Hz are infrasonic, while those above 20,000 Hz are ultrasonic.
Fascinating Phenomena:
Human hearing: the three smallest bones in the human body—the hammer, anvil, and stirrup—are located in the ear and amplify incoming vibrations to the inner ear.
Animal hearing: many animals hear beyond human range; for example, dogs hear higher frequencies, while dolphins can detect sounds from up to 15 miles away underwater.
Sound can boil water: Peter Davey created a device that can boil water in seconds, using only sound waves.
Sound can create light: Sonoluminescence is the emission of short bursts of light from imploding bubbles in a liquid when excited by sound. An intense amount of energy is created by the process as well.
Sonic booms: occur when an object, like a jet, travels faster than the speed of sound (Mach 1), compressing sound waves into a loud explosion-like noise.
Acoustic levitation: scientists can use standing sound waves to lift and suspend small objects in midair by balancing acoustic pressure against gravity.
