1)When the liquid is spun rapidly, the denser particles are forced to the bottom and the lighter particles stay at the top. This principle is used in:

Centrifugation.

Explanation:

When the liquid is spun rapidly, the denser particles are forced to the bottom and the lighter particles stay at the top. This principle is used in centrifugation.

Centrifugation can be defined as the process of separating particles from a liquid solution according to density, shape, size, viscosity through the use of a centrifugal force. In order to separate these particles, the particles are poured into a liquid and placed in a centrifuge tube. A centrifuge is an electronic device used for the separation of particles in liquid through the application of centrifugal force. Once the centrifuge tube is mounted on the rotor of the centrifuge, it is spun rapidly at a specific speed thereby separating the solution; denser particles are forced to the bottom (by moving outward in the radial direction) and the lighter particles stay at the top as a result of their low density.