A separation assembly for enabling separation of a fluid into first and second parts, comprising: a container having a first end , a second end , and a sidewall extending therebetween having an inner surface and defining a container interior , the container defining a longitudinal axis (L) between the first end and the second end ; and a separator body disposed within the container interior and having a through-hole defined therethrough, the separator body comprising: a float defining an upper surface of the separator body ; and a ballast defining a lower surface of the separator body and interfaced with the float , wherein the density of the ballast is greater than the density of the float , wherein the separator body is transitionable from a first position in which the separator body forms an interference fit with the sidewall of the container to hold the separator body in a stationary position during the introduction of the fluid into the container and the through-hole is provided in fluid-receiving alignment with the first end of the container , to a second position in which the through-hole is provided substantially perpendicular to the longitudinal axis (L) of the container , and in the first position, the separator body contacts the sidewall of the container at a location that is offset from a center of the upper surface of the float and at a location that is offset from a center of the lower surface of the ballast , and the through-axis (T) of the through-hole of the separator body is in a plane that is not parallel with a plane containing the longitudinal axis (L) of the container , characterized in that the through-hole 2. is a straight bore. a container having a first end , a second end , and a sidewall extending therebetween having an inner surface and defining a container interior , the container defining a longitudinal axis (L) between the first end and the second end ; and a separator body disposed within the container interior and having a through-hole defined therethrough, the separator body comprising: a float defining an upper surface of the separator body ; and a ballast defining a lower surface of the separator body and interfaced with the float , wherein the density of the ballast is greater than the density of the float , a float defining an upper surface of the separator body ; and a ballast defining a lower surface of the separator body and interfaced with the float , wherein the density of the ballast is greater than the density of the float , wherein the separator body is transitionable from a first position in which the separator body forms an interference fit with the sidewall of the container to hold the separator body in a stationary position during the introduction of the fluid into the container and the through-hole is provided in fluid-receiving alignment with the first end of the container , to a second position in which the through-hole is provided substantially perpendicular to the longitudinal axis (L) of the container , and in the first position, the separator body contacts the sidewall of the container at a location that is offset from a center of the upper surface of the float and at a location that is offset from a center of the lower surface of the ballast , and the through-axis (T) of the through-hole of the separator body is in a plane that is not parallel with a plane containing the longitudinal axis (L) of the container , characterized in that the through-hole 2. is a straight bore. <EOS>