Which device spins samples rapidly to separate elements based on weight?

Which device spins samples rapidly to separate elements based on weight?

• A. Cannula
• B. Centrifuge
• C. Counter
• D. Refractometer

Answer: (B)

Centrifugation uses rapid rotation to separate mixture components by density. When a sample is spun, it experiences a centrifugal force that pushes particles outward. Denser components move toward the outer edge or bottom of the tube, while lighter components stay closer to the center. Over time and at higher speeds, distinct layers form, making it possible to isolate different elements—such as separating plasma from blood cells or cream from milk. In practice, the speed, duration, and rotor type determine how cleanly the separation occurs. Other tools mentioned aren’t used to separate by density: a cannula is simply a flexible tube for accessing body cavities or vessels; a counter is used for tallying or comparing items; a refractometer measures refractive index to estimate concentration, not to separate components.

Centrifugation uses rapid rotation to separate mixture components by density. When a sample is spun, it experiences a centrifugal force that pushes particles outward. Denser components move toward the outer edge or bottom of the tube, while lighter components stay closer to the center. Over time and at higher speeds, distinct layers form, making it possible to isolate different elements—such as separating plasma from blood cells or cream from milk. In practice, the speed, duration, and rotor type determine how cleanly the separation occurs.

Other tools mentioned aren’t used to separate by density: a cannula is simply a flexible tube for accessing body cavities or vessels; a counter is used for tallying or comparing items; a refractometer measures refractive index to estimate concentration, not to separate components.