Sound Energy JSS3 Basic Science Lesson Note

Sound is a form of energy and is transferred in the form of a wave to the listener through a medium by vibration. Sound is transmitted through a medium in the form of vibration or wave reaching the human ear, the waves as sound. 

Sound is classified into two classes (i)  musical sound and (ii) noise

Musical sounds are caused by bodies performing regular vibrations. Examples of musical instruments are flute, trumpet, drum, guitar, piano, and gong.

Noises are caused by irregular disturbances such as collisions and explosions.

Sound requires a medium to travel. It can travel through the wire as well as through the air. Sound is also transmitted to metals and pipes. The sound may converted to electrical signals when traveling a long distance as in the case of a land telephone. Sound waves can be reflected in the same way as light waves when strike a hard surface such as a wall, rock, or concrete structure. The reflection of sound waves when obstructed by hard objects such as rock is called echo.

Sound waves can also be refracted when it passes from one medium to another. Sound can also undergo diffraction and interference.

Characteristics of sound waves

– Reflect

– Refract

– It needs a medium to travel, it is fastest in solid

Mechanism of Hearing

Sound waves entering the pinnae are directed into the auditory canal which makes the eardrum vibrate. The vibration sets the ossicles into a greater vibration. This vibration is greatly amplified in the middle ear, which causes the oval window to vibrate far more than the eardrum because of its smaller size. The vibration in the oval window is passed on to the endolymph in the cochlea and causes the membrane-carrying hair cells to vibrate. The vibration makes the hair cell set up a nerve impulse. The is carried through the auditory nerve to the auditory region of the brain where is interpreted as sound.

 ASSIGNMENTS

1. All objects  that produce sound have a common characteristic called   A. vibration  B.tuning fork  C pieces metal  D. sound
2. One of the characteristics of sound energy similar to light energy is  A.incidence  B.deviation  C. refraction  D.reflection
3. The part of the heart that is responsible for hearing is  A.semicircular canals B.auditory nerve  C.eardrum  D. pinna
4. The hole through which sound enters the human ear is called  A.tympanic membrane  B. auditory meatus  C. semi-circular canals
5. Echo is produced when sound is   A. incident  B. blocked  C. refracted  D. reflected
6. The matter through which sound is transmitted is called medium B.gong  C.flute  D.microphone
7. The bonelike structures found in the middle ear are called  A.blade  B. earbone  C. ossicles  D.pinna
8. Optic nerve is to the eye as ____________ nerve is to the ear  A.auditory  B.nerve endings  C.olfactory  D.papillae

9a. Define sound

b.State the S.I unit of sound energy

c.State four characteristics of sound