Separation Techniques in Science

Separation Techniques

• Sieving: separates particles of different sizes
• Decanting: separates a liquid from a solid by carefully pouring the liquid off the top.
• Magnets: separates magnetic materials from non-magnetic materials
• Filtration: separates a solid from a liquid using a filter
• Evaporation: separates a dissolved solid from a liquid by heating the mixture until the liquid evaporates, leaving the solid behind
• Crystallization: a specific type of evaporation where the dissolved solid forms crystals as the liquid evaporates
• Distillation: separates liquids with different boiling points by heating the mixture to vaporize the liquid with the lower boiling point
• Chromatography: separates substances in a mixture based on their different affinities for a stationary phase and a mobile phase

Floatation

• Plastic floats on water and can be scooped out with a net.

Separating Funnel

• Separates two immiscible liquids (liquids that don't mix) with different densities
• The less dense liquid floats on top.
• The more dense liquid is drained out of the bottom into a beaker.
• Once the lower layer is removed, the upper layer can be collected in a separate beaker.

Centrifuge

• A machine that creates a rotational force to separate particles by density
• More dense particles form a pellet at the bottom of the tube.
• The remaining liquid (supernatant) can be carefully removed.
• The supernatant can be spun again to separate remaining particles with different densities.

Centrifuge Applications

• Blood Separation: To separate blood into plasma, red blood cells, white blood cells, and platelets.
• Milk Separation: Separating cream from milk.
• Before Centrifugal Separators: Cream was separated by hand skimming, a labor-intensive and time-consuming process.
• Centrifugal Separator Design: Original separators were hand-cranked.

### Separation Techniques

• Sieving
  • Used to separate solid particles of different sizes.
  • Larger particles are retained on the sieve while smaller particles pass through.
• Decanting
  • Used to separate a mixture of a liquid and a solid when the solid is denser than the liquid and settles at the bottom.
  • The liquid is carefully poured off, leaving the solid behind.
• Magnets
  • Used to separate magnetic materials from non-magnetic materials.
• Filtration
  • Used to separate an insoluble solid from a liquid.
  • The mixture is poured through a filter paper.
  • The solid gets trapped on the paper while the liquid passes through.
• Evaporation (and Crystallization)
  • Used to separate a soluble solid from a liquid.
  • The liquid is heated until it evaporates, leaving behind the solid.
• Distillation
  • Used to separate liquids with different boiling points.
  • The liquid with the lower boiling point evaporates first, and the vapor is collected and condensed back into a liquid.
• Chromatography
  • Used to separate different substances in a mixture based on their different affinities for the stationary and mobile phases.
  • The mixture moves through a stationary phase, and the different substances travel at different rates, allowing them to be separated.

Floatation

• Used to separate less dense solid materials from water.
• Solids float on water and can be scooped with a net.

Separating Funnel

• Used to separate immiscible liquids of different densities.
• The less dense liquid floats on top.
• The separating funnel allows the denser liquid to be drained out from the bottom.

Centrifuge

• A machine that creates a rotational force.
• Used to separate particles of different densities in a mixture.
  • The denser particles form a pellet at the bottom of the tube after spinning.
  • The remaining solution on top is called the supernatant.
• The supernatant can be spun again at a faster speed to further separate remaining particles.
• The centrifuge is often used to separate blood components, such as red blood cells, white blood cells, and plasma.
• Milk can be separated into cream and milk using a centrifuge based on density differences.

Centrifuge Applications

• Blood Separation: Separating blood into plasma and red blood cells.
• Milk Separation: Separating cream from milk.
• Wastewater Treatment: Separating solid particles from water.
• DNA Isolation: Separating DNA molecules from other cellular components.

Separating Funnel and Centrifuge Notes

• Separating Funnel: A separating funnel is a piece of equipment used to separate two immiscible liquids, such as oil and water. The liquids are poured into the funnel, and the denser liquid is drained out from the bottom.
• Centrifuge: A centrifuge works by spinning a mixture at high speed, forcing the denser particles to the bottom of the tube. The remaining solution is called the supernatant.
• Blood Centrifugation: If you put freshly collected blood in a centrifuge, the red blood cells will form a pellet at the bottom, while the plasma will remain on top.
• Milk Centrifugation: If you put freshly collected milk in a centrifuge, the cream will form a layer on top because it is less dense than the milk.
• Centrifuge Tube: After centrifuging a mixture, the tube will contain a pellet of denser particles at the bottom and the supernatant, or the remaining solution, on top.

Test your knowledge on various separation techniques used in science! This quiz covers methods such as filtration, distillation, and chromatography, among others. Explore how these techniques work and their applications in separating mixtures.