I made something similar using shaders in construct classic, and i managed to get it to work with pixel shader 2.0, you should be able to do the same with WebGL shaders that support way more instructions way easier. This type of falling sand game requires either brute force efficient CPU work or a very cleverly designed parallel process on the GPU, both of which are difficult for a novice to pull off but entirely possible with javascript and WebGL. You probably wont get very good performance trying to make it with events.
falling-sand-on-gpu-through-pixel-shader_t78983
i used the technique to "simulate" seas of green vomit in my game super clean clean
http://gamejolt.com/games/arcade/super- ... ean/19382/
these were made using construct classic and custom shaders however, so i can't testify to how possible this is with C2
This doesn't actually use any type of "physics" technique at all, its a cellular automaton like conways game of life, with clever rules that make it look like physics