The added weight of the butter has an effect on the falling process, since the butter spreads throughout the slice. A piece of toast has inertia as it flips towards the floor, preventing its spin from stopping easily; it is usually only stopped by hitting the floor. This moment of inertia is determined by the speed at which the toast is flipping, combined with the size and mass of the toast. Because most toast is relatively uniform, they often land in a similar manner.