Centrifuge

Another common laboratory tool is the centrifuge! It separates substances based on their density, according to the rotation speed of the centrifuge. In a solution, denser substances sinks while less dense substances floats to the top due to gravity. The centrifuge replaces gravity with centrifugal force, which is created through rotation about the axis. With the centrifugal force, denser substances move outwards towards the periphery while less dense substances move towards the centre, that is why you see your pellet concentrated on one side of the tube!⠀
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The higher the rotation speed used, substances of lower difference in densities can be separated. E.g. We use low centrifuge speed to separate cells from media during cell passage or separate larger cells from smaller cells. Whereas we use very high speed to separate very small substances such as organelles & macromolecules. Hence, it is important to ensure that appropriate speeds for different experimental procedure are used, high-speed spinning is harsh for the cells and can kill them!⠀