The+Science+of+Sound

Jess Moss, Amy Sutherland, Lucy Drake & Chris Hebbron
 * The Science of Sound **



Sound is a form of energy. It is simply vibrations travelling through the air or some other medium to the ear where messages are passed to the brain for decoding.
 * What is Sound? **



Sounds travels outwards from a source in waves, "in shapes of ever-expanding spheres, a bit like the layers of an onion," (Peacock et al 2011). Sound travels in all directions, even around corners. Sound needs a medium through which to travel. This may be a solid, liquid or gas. It cannot travel through a vacuum because in a vacuum there are no particles to pass on the vibrations. This concept is not always easily understood but can be demonstrated with a bell jar, as in this video:
 * How Does Sound Travel? **

media type="youtube" key="q2pj9k1lrsM" height="315" width="420"

**Gases**: Most of the sounds we hear have been transmitted through the air. **Liquids**: Although our ears have not evolved to hear well under water, we can still hear muffled sounds when under water. Whales and other seas creatures can also hear each other under water.
 * Examples of sound travelling through a medium: **



**Solids:** It is difficult to appreciate the concept that sound can travel through solids as solids absorb some of the sound's vibrations, but simply pressing an ear against a table or door and tapping on it shows clearly that sound can travel through solids.

Wherever there are particles to pass on vibrations, sound can travel. Sound cannot travel through space.


 * Properties of Sound **

__ Frequency or Pitch refers to the number of sound waves per second. __
 * High pitched sounds have high frequency
 * Low pitched sounds have low frequency
 * Pitch is affected by the size, the length and the tightness of the object that is vibrating (the source of the sound)

__ Amplitude is the volume or loudness of the sound and describes the size of the sound waves. It is measured in Decibels. __


 * Loud sounds are made from larger sound waves (greater amplitude)
 * Quiet sounds are made from smaller sound waves (lesser amplitude)
 * Loudness is affected by the amount of energy put in to making a noise eg. how hard something is hit, plucked, shaken or scraped and the amount of matter vibrating

**What the National Curriculum Requires Children to Know About Sound...** __**KS1 - Light and Sound.**__ **Making and Detecting Sound.**
 * that there are many kinds of sound and sources of sound
 * that sounds travels away from sources, getting fainter as they do so, and that they are heard when they enter the ear

__**KS2 - Light and Sound.**__
 * Vibration and Sound.**
 * that sounds are made when objects, (for example, strings on musical instruments) vibrate but that vibrations are not always directly visible
 * how to change the pitch and loudness of sounds produced by some vibrating onjects (for example, a drum skin, a plucked string)
 * that vibrations from sound sources require a medium (for example, metal, wood, glass, air) through which to travel to the ear

**Suggestions for Teaching and Investigating Sound**

**References & Useful Resources**

CPG KS2 & 3 Science Revisions Guides

Cross & Bowden (2009) //Essential Primary Science.// Berkshire, Open University Press

Wenham, M. (2005) //Understanding Primary Science.// London, Paul Chapman Publishing **Wikis from fellow trainees**: http://mcruniprimarypgce.wikispaces.com/Sound http://mcruniprimarypgce.wikispaces.com/Sound+as+a+proverbial+pound