When users come in and continue to Buy bitcoin and invest more money into Mining and all that then it increases the price because the demand for it is increasing. When the demand increases then so does the price.Though when people start selling either due to they believe the price will drop because say it got some bad press or something serious happened with maybe a exploit found then the price would drop because people will be scared and start trying to sell it so they don’t lose the money that they have earned. What this results in is the price going down because more people are selling then buying.