I think bitcoin is so volatile because of the fact that there are many factors contributing to it, such as demand from the people the other cryptocurrencies that it beats. The more there are competitors for bitcoin, the more its value rises. In an economics class there are theories for this scenarios, although I have forgotten the exact term for it.
Certainly the factors affecting bitcoin volatility is the changes of market demands and supply because the fact that bitcoin market capacity is having a limited amount so it easily to fluctuate with respect to market changes, therefore its truly like the significance of the law for the supply and demand.