Now the next question is how exactly do we describe the rate at which different particles move inside our rotating test tube during the process of centrifugation? So in biochemistry, we describe the rate of the movement of the particles inside our test tube by using a quantity known as the sedimentation coefficient, and that is given with the lowercase S. So lowercase S is equal to the mass of that particle multiplied by one minus v bar multiplied by row divided by f. Now, in the next lecture, we're going to use physics to basically derive this equation. Now let's discuss what these quantities actually mean. So S is our sedimentation coefficient and it is given in units known as cevetberg units. Now M is the mass of that particular particle that we are examining. In this particular case, the mass is the mass of this blue biological particle.