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 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 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 of the through-hole of the separator body is in a plane that is not parallel with a plane containing the longitudinal axis 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 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 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 of the through-hole of the separator body is in a plane that is not parallel with a plane containing the longitudinal axis of the container, characterized in that the through-hole 2. is a straight bore.