surface tension and spheres
 

they didn't mention thermal difference..tiny object in motion is meeting a greater mass of warmer/cooler...
steel reveals this example I speak of.

Now we know why a single drop makes so many ripples... :)

Regarding the temp thing, I'd imagine, but I'm not sure, that both the water in the bowl and the water in the syringe were at room temperature - MIT's usually pretty good about those things.

Wanna see something cool? Drip water on a hot wood stove or something. It bounces off!