What  makes sound?

For a sound to be made and heard ,three things need to happen. First, an object vibrates.A vibrating object makes tiny,very fast back-and-fourth movements.For example, when a musician strums guitar strings, they vibrate.The vibration moves the surrounding air and produces waves of sounds.

Second,the sound waves pass into a medium . A medium is any substance through which the waves can travel.Sound waves may travel through many mediums. These include air, water and solid objects.Sound waves pass through mediums in all directions.

Third,some kind of receiver, such as the ear of a person,picks up the sound waves . The ear change sound waves into signals that travel to brain.The brain understand these signals as sound.

Speed of sound

The speed of the sound varies depending on what medium it is  travelling through.In air at a temperature of 70 degrees of Fahrenheit
[21 degrees of Celsius] sound travels at a speed of 1,129 feet [344 meters] per second.That it takes about five seconds to travel one mile.
In warmer air travels faster.Sound travels even faster through water and solid mediums such as iron , stone etc.

Pitch,intensity and quality

Every sound has 3 basic properties:pitch,intensity and quality. The pitch of a sound is how high or low it is. Faster vibrations cause sound with a higher pitch.The intensity of sound is how soft or loud it is.Intensity depends on the strength of the vibrations,stronger vibrations cause louder sounds .The quality or timbre, of a sound is how hash or pleasant a sound seems. 

Are all the sounds in the world are heard by man?

No there is a limit that man can hear sound . The frequency of human 's ear is  20 Hz to 20,000 Hz .The man cannot hear sound above those frequencies.

Then what is called as frequency?

Frequency means the number of vibrations that take place in a material per second.It is measured by Hz.

The frequency of other species.

Other species have a different range of hearing. For example, dogs can perceive vibrations higher than 20 kHz. As a signal perceived by one of the major senses, sound is used by many species for detecting danger, navigation, predation, andcommunication. Earth's atmosphere, water, and virtually any physical phenomenon, such as fire, rain, wind,surf, or earthquake, produces (and is characterized by) its unique sounds. Many species, such as frogs, birds,marine and terrestrial mammals, have also developed special organs to produce sound. In some species, these produce song and speech. Furthermore, humans have developed culture and technology (such asmusic, telephone and radio) that allows them to generate, record, transmit, and broadcast sound.

The animals that has a higher range of frequency

The animals that has a higher range of frequency

Sound recording

Sound recording, or audio recording, is the storage of sound so that they can be heard again . In professional and home recording studios ,special equipment records the music that  people listen to on compact discs[CD] and their computers .Sound recording is also used in radio,television and movies. 

How does the sound records?

Sound is caused by tiny vibrations that travels through the air as waves .Sound  recording devices use a microphone to change the sound waves into electrical signals  that resemble the waves. A play back device turns the electrical signals back into sound waves.  It sends the waves to loud speakers to reproduce the original sound.

1877 Edison phonograph Thomas Edison's first phonograph recorded sound when someone spoke into the recording sound box while turning the hand crank. The recording sound box pressed a needle-like object called the recording stylus against the tinfoil cover of a rotating cylinder. A person could play the recording back by turning the crank while pressing another stylus against the same tinfoil. Then the reproducer sound box would reproduce the original sounds.