Sound

Everything a person hears is called sound. Sound is a vibration or wave traveling through solids, liquids, or gases and can be heard. A sound begins by some type of mechanical movement which can include a person playing an instrument, a door slamming, or thunder in the sky. The molecules of these objects vibrate and in turn cause the surrounding molecules to vibrate, thus causing the sound to travel.

Without matter like a solid, liquid o gas, sound could not travel. It needs the vibration of molecules from the matter in order for there to be a sound that can be heard. Outer space is void of any objects and is a vacuum so there is no sound and it is very quiet. The solid, liquid, or gas that transports the sound is called a medium.

Next, the speed of sound is how fast the sound wave or the vibration travels through the object, medium, or matter. Depending on whether it is a solid, liquid, or gas, the sound will travel at different speeds. Sound will travel faster in water than in air, but much faster in steel.

The amount of moisture in the air will also affect the speed of sound. In dry air, sound will travel 768 miles per hour, but faster in water. At 768 mph, sound will travel one mile in 5 seconds through dry air, but four times faster in water, and 13 times faster through steel.

The term sound barrier is often heard when airplanes go faster than the speed of sound. When this happens, the plane breaks the sound barrier. They also create a sonic boom, which is a loud explosive-sounding noise that is caused by a number of sound waves that are forced together as the plane moves faster than sound.

Decibels are used to measure the loudness of sound. The more decibels the louder the sound. A whisper may only measure 15 to 20 decibels, but a jet engine may generate 150 decibels. Pain in the ears may occur if a person hears a sound measured at about 130 decibels, which can damage the ears or even cause a loss of hearing. This is why listening to loud music through headphones can be harmful.

Sound also includes a measurement called frequency. Frequency is related to the pitch of sound. For example, a thin guitar string that is plucked will vibrate faster and create a high sound or pitch. A thicker string will vibrate slowly and create a low sound or pitch. This is what leads to different musical notes.

Sound also helps humans talk and listen to each other. It is a very complex process and many parts of the body work together, but the vibration of vocal cords in the throat leads to sound. The mouth, tongue, and lungs also contribute to the sounds a human makes from their mouth.

Finally, acoustics is the study of sound and how it travels. Someone specializing in acoustics learns how sound moves, which is important when building auditoriums, theaters, and other types of buildings. In some places, like in a theater staging plays, it is important for sound to travel throughout the room, in a library however, it is more important to control the sound and prevent it from traveling. Using different materials on the walls or ceilings will help regulate the movement of sound waves.

In summary, sound is a vibration or wave traveling through solids, liquids, or gases and can be heard. Sound travels at different speeds depending on the medium that the sound wave travels through. The loudness of sound is measured in decibels and the pitch of sound is related to frequency. The study of sound and its movement is called acoustics.