GRADE 7
SCIENCE
Separation
Techniques
Discuss with a partner
how you would separate
the following mixtures…
Salt water
Ø  Muddy water
Ø  Nuts and bolts
Ø  Iron filings and sand
Ø 
Vegetable oil and
sand
Ø  Vegetable oil and
water
Ø  Salt and pepper
Ø 
Be prepared to defend
your answers!
DISCUSSION
QUESTION
Are the components you have
separated still mixtures, or are
they pure?
Why or why not?
SEPARATING
MECHANICAL
MIXTURES
Sorting
¢  separa'ng substances based on appearance (colour, size, texture) ¢  some recycling programs require the driver to separate glass, plas'c, and paper Floatation and Settling
¢  allow heavier materials to se=le to the bo=om of a liquid and extract them with a tool ¢  if a substance is light enough, it will float to the top of a liquid and a tool can be used to skim it from the surface Sifting
¢  separa'ng solids by size ¢  involves passing solid materials through a screen or mesh ¢  parts that are small enough to pass through are separated from larger ones that can t fit through ¢  different than filtra'on — 
— 
filtra'on is used to separate solids from liquids or gases siCing separates solids from other solids MAGNETISM
¢  some metals are magne'c because their component par'cles are a=racted to the par'cles within magnets ¢  A magnet can be used to separate magne'c materials (iron, steel) from others (plas'c dashboards, rubber 'res) SEPARATING
SOLUTIONS
Filtration
¢  separa'ng solids from liquids or gases ¢  when solu'on is poured through filter, solid parts are trapped, and liquid or gas pass through ¢  if the solid is small enough, it may s'll pass through the filter ¢  ex: salt dissolved in water Coffee filter
Oil filter
Colander
Furnace filter
EVAPORATION:
¢ Change
of state from a
liquid to a gas.
¢ Used to recover a solid
solute from a solution.
DISTILLATION:
¢  Uses
two changes of state:
evaporation and
condensation.
¢  It
allows you to recover
BOTH the solute and
solvent from a solution.
¢  Solution
is boiled, which vaporizes the solvent and
separates it from the solute
¢  Gas
condenses on a cool surface and is collected
INDUSTRIAL DISTILLATION TOWER
SEPARATION
TECHNIQUES IN THE
HOME:
¢ Colanders
¢ Clothes
dryers
¢ Window screens
¢ Coffee percolators
¢ Salad spinners
Any others?
SEPARATION
TECHNIQUES IN
INDUSTRY:
¢ Colanders
¢ Clothes
dryers
¢ Window screens
¢ Coffee percolators
¢ Salad spinners
Any others?