What are some key differences between sound and light waves?

Sound waves have mass, as they are the longitudinal (along the path of the wave) vibration shockwave of molecule, while light waves do not, as they are the transverse displacement of just energy.

Sound waves cannot travel in a vacuum, as they require a medium of massive particle to be transvered, but light wave can, as they are simply a form of energy.

In spite of this, the basic properties of waves still apply to both - light and sound can be reflected by objects, they can be refracted in different media, they have wavelength and frequency, and they can interfere to change the magnitude of a wave at any point.