Sound


 * Sound**



PITCH
 * Sounds occur when objects vibrate. These vibrations cause the air around the object to vibrate and these vibrations then enter the ear.
 * Sound can travel through solids, liquids and gases, although it travels through some objects better than others.
 * Sound travels in longitudinal waves.
 * We can hear sounds by sound waves vibrating the air particles around our ear. These then vibrate the air in our ear on to the ear drum. The ear drum then causes nerve impulses to be sent to our brain and this is how a sound is interpreted.
 * In this image, the sound of someone speaking into one tin would create a vibration of which would travel down the string to the other end. The person holding the tin can at the other end then hears the original sound.
 * Sound cannot be heard in a vacuum, as it needs something to travel through and vibrate. In a vacuum, there are no air particles to vibrate thus no sound is created.
 * @http://www.youtube.com/watch?v=ce7AMJdq0Gw&feature. This video shows how sound is produced in air and also how sound is produced in a vacuum. The bell jar demonstrates the difference between air particles being present to make sounds heard and a vacuum where sound cannot be heard.

AMPLITUDE
 * Pitch is how high or low a noise sounds.
 * A high frequency sound wave (vibrating very fast) produces a high pitch sound, for example a whistle, 1000hertz.
 * Slow vibrations cause a low pitch for example thunder with has a frequency measure of 50hz.
 * 50hz means that the sound wave would go past your ear 50times within a second.
 * Amplitude is a measure of energy.
 * The more energy a sound wave has the higher the amplitude.
 * Intensity is linked to amplitude and refers to the amount of energy a sound has over an area. The higher the amplitude then the higher the intensity.


 * Sound on the National Curriculum**


 * In Key Stage 1, children should be taught:- Making and detecting sounds - (a) that there are many kinds of sound and sources of sound; and (b) that sounds travel away from sources, getting fainter as they do so, and that they are heard when they enter the ear.
 * In Key Stage 2, children should be taught:- Vibration and sound - (a) that sounds are made when objects [for example, strings on musical instruments] vibrate but that vibrations are not always directly visible; (b) how to change the pitch and loudness of sounds produced by some vibrating objects [for example, a drum skin, a plucked string]; (c) that vibrations from sound sources require a medium [for example, metal, wood, glass, air] through which to travel to the ear.

Here is a video which includes two ways of visually showing how sound travels. The first example is great because it cannot be created in class. The second is one that we have been shown in lectures and is a great way to get children involved. Sound Through Air
 * Resources -**

Misconceptions about pitch seem to be common with pupils. Here is a video to show what determines the pitch of a sound. Pitch

This document contains sound activities and experiements. It includes yoghurt pots, so you know it's primary science!