How Sound Works - It is a vibration that begins with some mechanical movement, like slapping your hand down on a table. The atoms next to where your hand hit the table vibrate, causing adjacent atoms to vibrate.
QUESTIONS: How It Works - Have you ever heard of the sound barrier? Aircraft are said to be breaking this barrier when they travel faster than the speed of sound, a speed known as Mach 1.
Pitch and Frequency - Two important words to know when talking about sound are pitch and frequency. Frequency means how fast the wave is vibrating. Frequency is not the same as the speed at which the wave travels.
QUESTIONS: Pitch and Frequency - When we talk, obviously, we are also creating sound. Producing discernable speech is a complicated process involving many parts of the body.
Waves - A sound wave is a kind of wave that can be detected by the ears of many creatures. The wave begins with some mechanical movement, like plucking a guitar string.
QUESTIONS: Waves - Sounds waves are longitudinal waves. This means that as atoms vibrate and pass energy from atom to atom, the wave that they cause moves in the same direction as the vibration.
How We Hear? - Hearing is the sense that we use to perceive sound. We hear something when our ears translate those waves into something that is comprehensible to our brain.
QUESTIONS: How We Hear? - In addition to fluid, the inner ear contains an organ called the cochlea, which uses little hairs that vibrate with the waves in the fluid to translate the vibrations into electrical signals that the nerves then send to the brain.
Breaking the Barrier - It took nine flights before Yeager broke the sound barrier. The first took place on August 29th, 1947. Each subsequent flight was faster by .2 Mach. Mach is the unit in which the speed of sound is measured.
QUESTIONS: Breaking the Barrier - When the Glamorous Glennis reached Mach 1.06, about 700 mph, on October 14th, 1947, the crew on the ground heard a loud boom, the first sonic boom. The craft flew at supersonic (greater than sound) speed for 20 more seconds before Yeager cut the engines and glided safely back down to the ground.
The Hearing Barrier - The term sound barrier was first used during World War II when aircraft first began to try to travel faster than the speed of sound. As they approached that velocity, about 758 mph, they would begin to encounter the aerodynamic effects of compressibility.
QUESTIONS: The Hearing Barrier - Aircraft are said to be breaking the sound barrier when they travel faster than the speed of sound, a speed known as Mach 1. The Mach unit of measurement is named for Austrian physicist and philosopher Ernst Mach.
Sonic Boom - A sonic boom is the sound you hear when an object moves faster than the speed of sound. It is usually associated with military aircraft flying at supersonic speeds.
QUESTIONS: Sonic Boom - A sonic boom creates a very large amount of sound energy, as much as a million watts per square meter. The volume sometimes exceeds 200 decibels.
Ultrasound - An ultrasound (also called sonography) is a medical procedure that uses high-frequency waves to make pictures of the inside of the body.
QUESTIONS: Ultrasound - The most common use of ultrasound is on pregnant women. With an ultrasound, a doctor can monitor fetal development. Ultrasounds can also used to detect problems in certain fetal organs.
Different Types of Waves - Two of the most basic things that physicists study are light and sound. Many more advanced studies in physics have their basis in our understanding of how they work.
QUESTIONS: Different Types of Waves - Besides being slower, sound waves are also able to travel through substances (solids, liquids, and gases) that light waves are not. Light moves best through empty space.
Acoustics - The study of how sound moves and behaves is called acoustics. Just as ripples of water move away from a rock that is thrown into a pond, the waves travel away from the source of sound through both air and solids.
QUESTIONS: Acoustics - The term acoustics also refers to the science of controlling noise in buildings. Acoustics does more than just minimize the extent to which tones can travel.