Resources

This item is one of over 25,000 physical resources available from the Resources Collection. The Archive Collection covers over 50 years of curriculum development in the STEM subjects. The Contemporary Collection includes all the latest publications from UK educational publishers.

Waves - coherence and path difference

This video introduces explains the difference between the phase difference of a wave (measured in degrees) and the path difference of a wave (measured in metres of fraction of a wavelength). 

When waves are coherent and have a path difference that is a multiple of λ, then the interference is constructive. ...

Waves - diffraction gratings

This video begins by asking the question, “why do we see rainbow colours on the surface of a DVD?”.

Light from a laser is shone through a diffraction grating to demonstrate a diffraction pattern.  The terms 0^th, 1^st and 2^nd order maxima are introduced and explained using the...

Waves - optical fibres

This video recaps on the idea that light sent along an optical fibre requires total internal reflection for it to progress along its length. It explains that information is sent as a series of on – off signals.  However, if light rays take different paths they can be modally dispersed, and this can degrade the...

Waves - refraction and Snell's law

This video models refraction using a vehicle travelling from a concrete surface to a grass surface and shows how the forward wheel slows and so the vehicle changes direction.

A diagram is then constructed to develop Snell’s law, i.e., the angle of incidence (from air) is proportional to the angle of...

Waves - superposition

This video explains how two waves passing through each other interact through the process of superposition.

The resultant interference of waves at phase differences of 0⁰ or 360⁰ is constructive, they are additive.  Whereas phase differences of 180⁰ produce destructive interference, i.e., they cancel each...

Waves - total internal reflection and critical angle

This video begins by showing a demonstration of total internal reflection (TIR) through a semi-circular glass block.

It develops an understanding of TIR by showing that as the angle of incidence (θ_i) increases so too does the angle of refraction (θ_r).  Eventually, as  θ_i is...

Waves - two source interference

This video shows how interference from two sound wave sources can produce both constructive (louder sound) and destructive (softer sound) interference patterns.  A demonstration using microwaves reinforces this idea. Microwaves are generated and passed through a double slit.  The resultant interference of waves is...

Waves - Young's double slit experiment

This video explains the observations when two coherent light waves interact to form fringes.  A diagram is used to show that

λ = ^(ax)/_d, where a = slit separation and D = the distance between the slit and the projection screen, and x = distance between fringes. From these measurements...

This item is one of over 25,000 physical resources available from the Resources Collection. The Archive Collection covers over 50 years of curriculum development in the STEM subjects. The Contemporary Collection includes all the latest publications from UK educational publishers.