2. WHAT IS SOUND?
Vibrations transmitted through an elastic solid or a
liquid or gas, with frequencies in the approximate
range of 20 to 20,000 hertz, capable of being
detected by human organs of hearing.
Transmitted vibrations of any frequency
3. HEARING
is the ability to perceive sound by detecting
vibrations, changes in the pressure of the
surrounding medium through time, through an
organ such as the ear. Sound may be heard
through solid, liquid, or gaseous matter. It is one of
the traditional five senses. The inability to hear is
called deafness
4. How sound travels?
Sound waves are essentially variations of pressure that exists,
To help visualize the nature of sound waves, think of yourself in a tub of
water with a plastic toy boat floating in front of you. If you create
waves by pushing your hand along the top of the water, the waves
push against the boat and move it from one end of the tub to the
other. Now think of the waves and the boat as sound. As the waves
move along, so does the boat (which is also the sound).
Sound wave
a sound wave is an example of an oscillation. An oscillation is a
regular backward and forward (or upward and downward) movement.
Speed of sound
The speed of sound is the distance travelled during a unit of time by a
sound wave propagate through an flexible medium.
Echo
an echo is a reflection of sound, arriving at the listener some time after
the direct sound.
5. MORE ON…
The Pitch of a sound means how high or low the sound is.
The Frequency of a sound is the number of sound
vibrations set up in 1 seconds. It is measured in
hertz(Hz).
The loudness of sound depends on the amplitude
or size of the vibrations.
The greater the amplitude, the louder the sound
6. We cannot actually see sounds but we can see sound
with the help of……
Oscilloscope
an instrument in which the variations in a fluctuating electrical
quantity appear temporarily as a visible wave form on the
fluorescent screen of a cathode-ray tube
7. HOW DO WE HEAR SOUND?
You can hear because your ears convert the vibrations of a
sound wave in the air into signals that your brain interprets as
sound. When the vibrations of a sound wave enter your ear,
your eardrum and a set of tiny bones in your ear (the wellknown hammer, anvil, and stirrup) amplify those vibrations. In
your inner ear, these amplified vibrations move tiny hair cells
that then convert the vibrations into nerve impulses sent to
your brain. Your brain then interprets these nerve impulses as
sound.
