Resources by Physics Online
Displaying 71 - 80 of 81
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 0th, 1st and 2nd 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 (θi) increases so too does the angle of refraction (θr). Eventually, as θi 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...
Waves in a solid
The speed of a wave in a solid is investigated in this video. A signal generator and length of elastic are used to measure the frequency and wavelength of a wave, which allows wave speed to be calculated.
Waves on water (distance and time)
A ripple tank is used in this video to calculate the speed of a water wave by measuring the distance and time. This is a GCSE Combined Science and Physics Required Practical.
Waves on water (frequency and wavelength)
A ripple tank is used in this video to calculate the speed of a water wave by measuring the frequency and wavelength. This is a GCSE Combined Science and Physics Required Practical.