How Does a Centrifuge Separate Substances?

When a mixture is spun rapidly, denser components are pushed outward (toward the bottom of the tube) while lighter components stay closer to the centre. In a blood centrifuge, spinning at about 3,000 RPM separates blood into three layers: red blood cells (heaviest) at the bottom, a thin buffy coat of white blood cells and platelets in the middle, and plasma (lightest) on top. Ultracentrifuges, spinning at over 100,000 RPM and generating forces exceeding 1,000,000 g, can separate viruses, proteins, and even isotopes. Gas centrifuges enrich uranium by exploiting the tiny mass difference between uranium-235 and uranium-238 hexafluoride molecules.