Sound and music
Introduction
Why do we see lightning before we hear the thunder? How do we amplify
sound and how do we reduce it? How is it we can hear at all? Sound
is all around us every day and it is important for students to understand
how and why we hear in order to manipulate their surrounding environment.
Key concepts of sound and music
The activities in this topic are designed to explore the following
key concepts:
Early years
- We hear sound with our ears.
- Our sense of sound is very sharp.
- Sound travels through air.
- Sound travels through water and solid objects.
- We use two ears to judge where sounds come from.
- Sound bounces off surfaces (echoes).
- Sound is caused by vibrating objects.
Middle years
- Sound can vary in pitch (or frequency) and loudness.
- The pitch (or frequency) of sound is related to the speed of vibration
of the sound source. The more vibrations per second, the higher the
pitch.
- The loudness of sound is related to the size of vibration of the
sound source: the larger the size of vibration, the louder the sound.
- Sound needs a material medium through which to travel.
- Sound travels faster through solids and liquids than through air.
- Sound is a travelling vibration that moves through a medium such
as air, water or solid objects.
- Sound can bend around corners and spread out after passing through
gaps.
- Objects have their own natural vibration pattern and can give a
characteristic note when hit (or blown).
- Large or long objects vibrate more slowly, causing sounds of lower
pitch (or frequency).
- Objects can be made to vibrate in sympathy with others that have
the same pitch (or frequency).
- Sounding boards amplify sound, and are important in instruments.
- Vibrating strings form the basis of stringed instruments.
- Vibrating air is the basis of wind instruments.
Students' alternative conceptions of sound and music
Research into students' ideas about this topic has identified the
following non-scientific conceptions:
- Students find it difficult to express a mechanism for how sound
travels.
- The loudness and pitch (or frequency) of sounds are confused with
each other.
- You can hear and see a distant event at the same moment.
- Hitting an object harder changes its pitch.
- In a telephone, actual sounds, rather than electrical impulses,
are carried through the wire.
- Sound moves faster in air than in solids (air is 'thinner' and
forms less of a barrier).
- Sound moves between particles of matter (in empty space) rather than
matter.
- Sound can travel through space.
- In wind instruments, the instrument itself vibrates, not the internal
air column.
- The pitch of whistles or sirens on moving vehicles is changed by
the driver as the vehicle passes.
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