### Waves, light and simple harmonic motion video lessons to buy

These topics on progressive waves are split into four sections, that is in the basic properties of waves and light, interference, wave particle duality and standing waves.

These are followed by details of the videos on standing or stationary waves.

At the bottom of the page is an example from the section - an introduction to standing waves

Basic Properties

Refraction 5m 30s.    (In GCSE, 14 to 16 years, collection also suitable for A level introduction)

Explaining Snell’s law and the mechanism of refraction.

Total internal reflection 4m 25s.    (In GCSE, 14 to 16 years, collection also suitable for A level introduction)

An explanation of how TIR occurs and the relation pf the critical angle to the refractive index/ Snell’s law

Transverse and longitudinal waves 4m    (In GCSE, 14 to 16 years, collection also suitable for A level introduction)

Illustrating the properties of both together with amplitude, wavelength and frequency and the connection to wave speed.

Diffraction water waves 2m 30s.     (In GCSE, 14 to 16 years, collection also suitable for A level introduction)

Explaining diffraction using water waves at corners and at wide, narrow and double slits.

The Doppler effect 4m 40s.       (In GCSE, 14 to 16 years, collection also suitable for A level introduction)

Demonstrations and explanations of the Doppler effect with reference to sound, light and red shift.

Interference

Interference patterns 5m      (In GCSE, 14 to 16 years, collection also suitable for A level introduction)

Explaining constructive and destructive interference and path difference.

Young’s slits 4m      (In GCSE, 14 to 16 years, collection also suitable for A level introduction)

The classic experimental method of measuring the wavelength of light demonstrated and explained.

How a diffraction grating works 3m 35s.

An explanation of the function of a diffraction grating detailing path difference.

Measuring the wavelength of light with a diffraction grating 3m

showing experimental details and the calculation.

Wave/ particle duality

The Photoelectric effect 5m

An explanation of the photoelectric effect and the influence that the discovery of this had on the theories about the nature of electromagnetic radiation.

Measuring Planck's constant 6m

A demonstration of the method of measuring the constant using a light emitting diode.

Polarization 7m
Starting with an overview explanation of what is meant by polarization and the standard demonstration of crossed polaroids and then moving on to explain how polaroid filters are used to reduce glare, increase contrast in photography, to analyse stress in perspex shapes and the use in 3D imaging.

Standing waves

Standing Waves- an introduction  8m

This video tutorial is in four parts illustrated throughout by demonstrations, diagrams and animation. A standing wave is produced by interference with the wave travelling in one direction and its reflection travelling the opposite way. A standing wave is a fixed pattern of vibration - hence the term “standing wave”. The fundamental frequency and harmonics of standing waves in a system are shown and the importance of understanding the waves to music and structures is briefly explained.

Standing waves in wires   13m

Starting with an overview of what a standing wave is we look at the effect of mass per unit length, tension and length of a string on the frequency of oscillation of the fundamental and then show the second harmonic.

There is an animation showing how the standing wave is formed by the wave meeting its reflection, an explanation of the measurement of the wavelength and frequency and important practical examples of standing waves. Finally an explanation of using a second source, a tuning fork, to match to the frequency of a string through resonance.

Standing waves in tubes 13m

An brief overview is followed by a demonstration of  matching the note of a tuning fork to the fundamental note of the tube and an explanation of the graphical representation of the wave together with an animation of the molecular movement. The video demonstrates how the wavelength is measured and then the velocity of sound in air can be calculated.

A simulation of the molecular motion at the second harmonic is shown and measurements explained on the more accurate determination of the velocity of sound taking into account the end correction. Finally a brief explanation of standing wave in an open tube is provided.

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