1. Grade 7 Science
Separating Mixtures

2. SEPARATION TECHNIQUES
How do we separate heterogeneous and homogeneous mixtures?

3. Separation of Heterogeneous Mixtures
Mechanical Sorting:
Used to separate the parts of a
mixture based on properties such
as particle size.
Examples:
floatation (this help you to skim the fat off soup)
magnetism

4. magnetism
floatation

5. FILTRATION: A common way to separate solid particles from a mixture.
The filters can have holes of varying sizes… small to microscopic.

6. Oil filter
Coffee filter
Colander
Furnace filter

7. 3. EVAPORATION: Change of state from a liquid to a gas.
Used to recover a solid solute from a solution. As the liquid (solvent) evaporates, the solute is left behind. Example: salt water

9. DISTILLATION:
Simple distillation uses two changes of state: evaporation (solution must boil)and condensation (when cooling occurs).
It allows you to recover BOTH the solute and solvent from a solution.

10. Simple Distillation Evaporation Condensation
Residue (solute) stays behind
condenser
Distillate (solvent) is collected here

11. Fractional Distillation
Fractional distillation is a process that uses the boiling points of substances to separate a complex mixture into its parts.
The process is done in a two tower structure:
shorter tower- petroleum is heated to change it into a mixture of gases.
taller tower – gases are pumped here and the hot gases rise and cool.

12. PAPER CHROMATOGRAPHY:
Used to separate the colored substances in a mixture such as ink.
Used to separate the solvents in a mixture.

14. SEPARATION TECHNIQUES IN THE HOME:
What do these separate?
Colanders
Clothes dryers
Window screens
Coffee percolators
Salad spinners
Any others?