well the risk depends on the amount you put in like in anything, my estimation is that within 1 month it on average moves around 10%
You are right, All of risk depend on the amount you put it. By the way, I think investment in bitcoin is not too risky. because, In a long term, bitcoin is a profitable investment. So we don't worry how much we invest in bitcoin.
We cannot be sure that bitcoin will only bring positive news for us in future as there is also a possibility that price will start going down so its never wise to invest all money in bitcoins and to be on safer side its always good to invest your money in multiple products.