Waves are disturbances that travel through space and carry energy.
Sound waves are longitudinal waves and can be reflected, refracted and diffracted like all waves. They are mechanical vibrations of particles that can be detected by the human ear. Ultrasound is outside the human range of hearing. See Sound.
Reflection and Refraction
Reflection of light, angles of incidence and reflection. Refraction is the change of direction from normal. Total internal reflection (TIR) occurs at the critical angle, and is used in fibre optic cables. See Reflection and Refraction.
Radio waves are used in communication, they travel round the world as ground, sky or space waves. They send signals as AM or FM: amplitude of frequency modulation. Their diffraction around hills (short or long wave). See Radio Waves.
Properties of Waves
Amplitude, wavelength and frequency defined. The wave equation linking velocity, frequency and wavelength and some example calculations. Waves can either be transverse of longitudinal. See Properties of Waves.
Light is just part of a continuum of waves called the electromagnetic spectrum. This spectrum includes many types of wave that you will recognise including X-rays and infra-red. Properties and uses of these. See ElectroMagnetic Spectrum.
The various components of a communication system. Transmitting and receiving signals, either digital or analogue and the various benefits. Problems of attenuation and noise. How information is read from a CD. See Communication Systems.