1) Sound is created by vibrations that cause air particles to bump into each other, transmitting sound waves. 2) In wind instruments like flutes, vibrating air makes sound by moving air particles back and forth to create sound waves. In string instruments, pressing and releasing strings at different lengths causes them to vibrate at different frequencies. 3) Sound needs a medium like air, water or other material to travel through as it is transmitted by particles colliding in the medium from one location to another.

1.
What is Sound?
Sound is a type of energy made by vibrations. When any object vibrates,
it causes movement in the air particles. These particles jump into the
particles close to them, which makes them vibrate too causing them to
bump into more air particles. This movement, called sound waves.
Picture a store thrown into a still body of water. The rigs of waves
expand indefinitely. When the vibrations are fast, you hear a high note.
When the vibrations are slow, it creates a low note.

2. How do Wind Instruments make
Sound?
In wind instruments, like the flute and trumpet,
vibrating air makes the sound. The air particles
move back and forth crating sound waves. Blowing
across a flute’s blow hole sets up Slinky like waves
in the tube. In the clarinet, a vibrating reed gets the
waves started.

3. How do String Instruments
make sound?
Stringed instruments are played by pressing
the fingers down on the strings. This
pressure changes the strings’ length,
causing them to vibrate at different
frequencies and making different sounds.
Shortening a string makes it sound higher.

4. What is the frequency of sound
waves?
When we draw a sound wave, the wave peaks and valleys are
close together or far apart. Sound waves vibrate at
different rates or “frequencies” as they move through the
air. German physicist who experimented with sound in the
19th
century. Amplitude is the objective measurement of
the degree of change in atmospheric pressure caused by
sound waves. Sounds with greater amplitude will produce
grater changes in atmospheric pressure from high pressure
to low pressure. Amplitude is almost always a
comparative measurement, since at the lowest-amplitude
end, some air molecules are always in motion and at the
highest end, the amount of compression and rarefaction
though finite, is extreme.

6. Pitch and Frequency
A sound wave, like any other wave, is introduced into a medium by a
vibrating object. The vibrating object is the source of the disturbance
could be the vocal cords of a person. Sound is transmitted by
particles in a solid, liquid or gas colliding with each other. It is a
wave which is created by vibrating objects and propagated through a
medium from one location to another.
The speed of sound in an ideal gas is independent of frequency, but it
weakly depends on frequency for all real physical situations. It is a
function of the square root of the absolute temperature, but is nearly
independent of pressure of density for a given gas

7. ss ure. Amplitude is almost always a comparative
The speed of sound is inversely dependent on square root, since sound in gases is a
type of compression. However, the speed of sound varies from substance to substance.
Sound travels faster in liquids.

8. Audible and inaudible sounds
Audible and inaudible sounds are relative terms.
Audibility of sound depends upon capability of ear.
Hence the sounds having frequencies above and
below this range are inaudible sounds for the human
beings. Ultra sonic sound is audible for such
creatures and the same kind of sound is inaudible to
the human beings.

9. A percussion instrument is a musical
instrument that is sounded by being struck
or scraped by a beater. The percussion
family is believed to include the oldest
musical instruments.

10. Sound is transmitted by particles (atoms or molecules) in a solid, liquid or gas colliding
Air particles moves in a to and fro position where they collide with each other to form a
cluster then they rebound from each other. The air particles do not move over a large
area but, carry the sound by air particles.

11.
Sound Needs a Medium to Travel
The origin of sound is always some vibrating body. In some
cases the vibrations of the source may be very small or
very large that it may not be possible to detect them.
Human voice originates from the vibrations of the vocal
chords. Sound travels in the form of longitudinal wave
and it requires a material medium for its propagation. This
structure helps you determine the direction of a sound. If a
sound is coming from behind you or above you, it will
bounce off the piano in a different way than if it is coming
from in from of you or below you. Your brain determines
the horizontal position of a sound by comparing the
information coming from your two ears. If the sound is to
your left, it will arrive at your left ear a little bit sooner
than it arrives at your right ear.

12. Sound Needs a Medium to Travel
The origin of sound is always some vibrating body.
In some cases the vibrations of the source may be
very small or very large that it may not be possible
to detect them. This type of vibrations is produced
by tuning fork, drum, bell, the string of a guitar
etc. Human voice originates from the vibrations of
the vocal chords and the sound from the musical
instruments is due to the vibrations of the air
columns. Sound travels in the form of longitudinal
wave and it requires a material medium for its
propagation.

13. Catching Sound Waves
The pinna, the outer part of the ear, serves to "catch" the sound
waves. Your outer ear is pointed forward and it has a
number of curves. This structure helps you determine the
direction of a sound. If a sound is coming from behind you
or above you, it will bounce off the pinna in a different way
than if it is coming from in front of you or below you. This
sound reflection alters the pattern of the sound wave. Your
brain recognizes distinctive patterns and determines whether
the sound is in front of you, behind you, above you or
below you.

14. Ear diagram courtesy NASA

15. Percussion instrument
The percussion section of an orchestra, however,
traditionally contains in addition many instruments
that are not, strictly speaking, percussion, such as
whistles and sirens. On the other hand, keyboard
instruments such as the celesta are not normally part
of the percussion section, but keyboard percussion
instruments (which do not have keyboards) are
included.

16. Air particles moves in a to and fro position where
they collide with each other to form a cluster
(compression) then they rebound from each
other, the same effect of hitting a ball against a
wall (rarefaction) - i.e. a series of mechanical
compressions and rarefactions. Sounds are
carried this way by the air particle in a outward
fashion similar to ripple in a pond as it
continues to collide with air particles.