This is a chapter in physics. I class X and a importantchapter

1. Sound Energy

2. What is sound?
 Sound is
– A form of energy made by vibrations.
– When an object vibrates it causes the air particles
around it to move.
– These particles bump into particles close to them
and this continues until they run out of energy.

3. Try this:
 Putyour finger on your neck and say “aah”
as loud as you can.
 Now say it as soft as you can.
 You can not only hear the sound, but you can
feel the vibration inside your throat.

4. How does sound travel?
 Soundtravels through all forms of matter—
gases, liquids and solid.
 These are called the medium.
 Sound cannot travel through a vacuum.

5. What is pitch?
 Pitch is how high or how low a sound is.
 This is a high pitched sound.
 This is a low pitched sound.

6. How does sound travel?
 Sound passes through the medium as
longitudinal waves.
 When the vibrations are fast you hear a
high pitch. When they’re slow, you hear a
low pitch.
High Pitch Low Pitch

7. How else can we change sound?
 We can make it louder or softer by changing
the amplitude of the height of the wave.
 The higher the amplitude, the louder the
sound. The lower the amplitude the softer
the sound.
Louder
Softer

8. How do musical instruments create
sound?
 Itdepends on the type of instrument. There
are four types.
– Woodwind
– String
– Percussion
– Brass

9. Woodwinds Instruments
 Woodwinds make music by blowing on the
top of the instrument or on a reed.
Clarinet
Bassoon
Oboe
Flute
Piccolo

10. String Instruments
 Strings make music by plucking or
strumming the strings.
Cello Guitar Harp
Violin
Electric
Guitar

11. Percussion Instruments
 Percussion instruments make music by
striking, shaking or scraping them.
Tambourine Piano
Drum
Xylophone Maracas
Cymbals

12. Brass Instruments
 Brass instruments make music by buzzing
lips while blowing.
Trombone
French Horn
Tuba
Trumpet

13. Did you know?
 Sound travels 4 times faster through water
than through air.
 There is no sound in space.
 Geologists use their knowledge of how sound
travels through rocks to help them find oil
fields.