The wave: v = fλ v: speed (m/s), f: frequency (Hz) λ: wavelength (m) As a wave passes through different media, its frequency stays the same. Light is not a continuous wave as shown in this simulation... light is actually comprised of discrete photons.
reflection: angle of incidence = angle of reflection
Waves are 'flipped' when reflected off a medium of greater refractive index. Waves are not 'flipped' when reflected off a medium of less refractive index. A flip: the wave is inverted... it has a 180 degree phase change.
A wave that passes from one medium into another of the same refractive index is not reflected by their boundary.
reflectance: When light passes from air to glass, or from glass to air, for instance, only about 4% of incoming light is reflected from its surface. So, this simulation is not accurate. If this simulation showed just 4% of the light being reflected, the reflected waves would be almost straight lines... not very useful for the student.
refraction: The refractive index of a medium, n, shows us how slowly light passes through that medium. Bigger n --> slower light. vacuum n vacuum = 1, vacuum n air = 1.0003, vacuum n glass ≈ 1.5, vacuum n diamond = 2.42
The speed of light in a medium = speed of light in a vacuum / n
If a wave passes from medium A into medium B at an angle, and their refractive indices differ, then the direction of the wave will change: nA sinA = nB sinB
A practical use: If the thickness of the thin film is zero, and its refactive index is greater or less than that of the media that surrounds it, then the two reflected waves will cancel each other out for all frequencies, once they leave the thin film. This is because there's always only one wave flipped and there's zero path difference... this is how anti-reflective coating works. Manufacturers strive to make the thinnest coating possible with the greatest refractive index possible. And a side note... the typical thickness of a soap bubble is about 500 nm. The top is thinner, the bottom is thicker.