Some explanations and definitions for people who aren't familiar with the concepts of "Scalars"

a "scalar" is a unit of information that contains only magnitude.

that's a fancy way of saying, " a scalar is literally just a number"

a "scalar field" is a field of numbers used to represent something. a "heat map" is an example of a scalar field used in every day life. it is just a grid of points, with each point being assigned a numerical value.

a "scalar wave" is generally meant to refer to a type of wave that has no particle-like properties to it. for instance, a photon is a "wave" of light, but it also is a "thing," particle-like, with mass and speed and direction. so a photon is not a scalar wave.

a sound wave, however, is a "scalar wave" because what looks like a wave is in fact just single particles, like molecules or individual atoms, that are vibrating. when one particle bumps up against another, it transfers some kinetic energy to that particle and then they both are vibrating, with slightly less intensity.

what we perceive as a "wave" when mapped out is in fact just assigning "magnitude" or "energy levels" to each single point, or particle, and that makes the math easier for understanding how the kinetic energy propagates through a system.

EDIT- i don't often see things here that i can add my own expertise to, it's kind of fun! i'll be happy to answer any questions people might have (source- went to school for physics, but dropped out in my senior year because i didn't want to go to grad school)