The IEC Diffraction Kit is a low cost and unique instrument to teach the principles of diffraction. The kit is self contained and housed in a small plastic box. A mono filament lamp provides a line source of light and it is viewed through various single and double slit sets produced photographically and supplied in the kit. An adjustable slit is provided and a set of colour filters to observe different patterns of different colours. A simple scale is mounted behind the light source to measure the distances between the dark and light bands of light.