Buoyancy is caused by an accelerating force. Another name for this accelerating force is called gravity. Different density materials will stratify in a centrifuge. A centrifuge creates a centripetal acceleration where heavier substances will sling outward.

Scientists using the 'Standard Model' don't know what causes gravity but its existence is without question.

Free thinkers using the 'theory of aether' believe gravity to be caused by static electricity.

Thinking that 'gravity' has been debunked is utterly ludicrous.