Take long lab cylinder filled with water. Into the water, drop many little lead balls and also many little plastic balls that are much less dense than water. Seal the cylinder and send it to the ISS onboard the coming Atlantis shuttle flight. In the near weightlessness of the ISS, shake the cylinder to spread the balls more or less evenly over the length of the cylinder. Then mount the cylinder vertically (relative to Earth), with its center on the station’s center of mass. Assume that the ISS keeps the same side pointing to Earth and that for a fair period there are no station movements due to positioning thrusters, astronaut movements, space-walks etc... Where in the cylinder will the lead and the plastic balls respectively settle?