1. Sound. Qualities of sound

Music is made by sound. But, what is sound made of? What is it?

When we hit an object, when we pluck a tight string, when we blow through a tube, when we speak and sing; we make sounds.

In order to turn sound into music, there must be an expressive intention.

The first step will be to work on the different qualities of sound, which have their own graphic representations on the staff: conventional notation symbols, as well as the so called alternative graphic notation.

	We are going to learn to...	Basic skills
Performance and creation	Recognize sound as a physical phenomenon. Experiment with sound, noise and silence as means of musical and personal expression. Use our voice, our body, objects and musical instruments in order to investigate the different qualities of sound, and also to enhance its expressive possibilities. Identify the qualities of sound and their representation with alternative graphic notation. Creatively investigate the different acoustic and musical possibilities of objects. Show interest in the composing and improvisation activities, and respect their classmates’ creations. Actively participate in the different musical activities by playing different roles, providing ideas and contributing to the perfection of the common task.	CCL CMCT CPAA CSC SIE
Listening	Recognize sound and silence as constituent parts of music. Appreciate silence as a requirement in order to take part in the listening. Identify the work of the different qualities of sound in the listening. Describe a composition’s parameters by using alternative graphic notation. Identify everyday situations in which sound is indiscriminately used, analyze its causes and provide possible solutions.	CMCT CPAA CSC SIE
Musical and cultural contexts	Become aware of the problems created by noise pollution and its consequences. Show interest in discovering different types of music and expanding their own musical preferences while adopting an open and respectful attitude. Value the need of handling different basic musical concepts in order to be able to talk about and judge music. Clearly and accurately communicate their knowledge and musical opinions, verbally as well as in writing. Read different types of scores as backup for the musical activities of the class.	CCL CMCT CPAA CEC
Music and technology	Easily find their own way with the necessary technological resources for recording and playing music. Use the available computer resources in a practical way in order to learn and investigate music. Easily handle the right sources and procedures in order to carry out the proposed tasks. Become aware of the contribution of music to the human experience, and show a more critical attitude towards the indiscriminate consumption of music.	CCL CMCT CD

1 Sound

1.1. How it is produced

Sound is produced when an object vibrates and that movement travels through sound waves until it reaches our ears.

↑ The vibration of an object travels through sound waves.

1.2. How it propagates

Sound propagates at high speeds. The waves travel through the air at 340 meters per second, and they are transmitted the same way waves spread on water when we throw a stone.

Usually, sound travels through air, but it can also travel through other mediums like water or solid objects. In fact, sound travels faster through water (1.435 m/s) and even faster through materials like wood (3.900 m/s) or iron (5.000 m/s).

1.3. How we hear

Sounds are picked up by a very thin membrane in our ear, the eardrum, which connects the outer and middle ear. When sound waves hit the eardrum, the information produced by its vibration is transmitted to the brain.

Reverb and echo

Reverb is produced when sound waves find obstacles on their way. They are reflected or bounced back in the opposite direction of the sound source.

Echo is a kind of reverb that creates the repetition of sound. When the time-lapse between the emitted and the reflected sounds is wide enough, we perceive them both separately.

The echo and the reverb of sound are very useful phenomena of nature. For example, they allow bats find their way while flying; and make it possible for sailors to measure the depth of the sea or let them know where a school of fish is.

The eardrum’s vibrations are turned into nerve impulses. They transmit the information to the brain.

ACTIVITIES

If you put your ear to the table and hit the wood gently with your fingers, you’ll notice how well sounds propagate through solid objects. Try to make it louder and softer putting your ear away from the table. Write your conclusions.