Camicus

First off, I was debating whether to put this here or in the science discussion. Since we use to so much in KSP I put it here. (Sorry if it is in fact in the wrong section) The formula that I have seen everywhere involves isp * 9.8, but what exactly does the 9.8 represent? From what I gathered, it is just isp * g and calculates the exhaust velocity. But why is it 9.8 instead of 9.81? Have I completely misunderstood something here?