The Following is a simple formation using a total of 8 points. The point here is the structure we see when the points are mocing. Does the structure we see really exists?
If you think yes the structure exists, then look at each point by closing all other points and then identify how the structure is really formed. Plenty of such math interactives are used in our courses.
Reflection and refraction occur when the wave speed changes as it enters a new medium. Part of the wave refracts into the new medium, and part of the wave reflects back into the old medium. Play with the following interactives, create your own and share with your friends and others.