1. 8th Grade Physical Science Presented by Betsy Sanford
Mixtures on My Mind
8th Grade Physical Science
Presented by Betsy Sanford

2. Classification and Matter
to sort by characteristics, traits, properties, etc.
used for identification, for study, for learning, for uses of matter
Types of Matter
elements (pure substances)
mixture (combinations of substances made by physical changes)
compound (pure substances, combinations of substances made by chemical changes)

3. Properties of Mixtures
May be solid
alloys like jewelry metals
May be liquid
like tea and lemonade
May be gas
like air
May be any combination of pure substances or compounds
The individual substances are combined without changing themselves

4. Types of Mixtures Solution substances dissolved in other substances
solute + solvent = solution
the ability to dissolve is called solubility
water is the universal solvent
ex. - Kool-Aid
diluted = more solvent, more water
concentrated = more solute

5. Types of Mixtures Suspension Colloid
particles may spread throughout the mixture, but will settle
particles scatter or block light, large enough to see
ex. - snow globe, oil and vinegar salad dressing, trail mix
Colloid
particles will not settle
particles will scatter light
are not large enough to see
ex. - dairy products, Jell-O

6. Classes of Mixtures Homogeneous Heterogeneous
looks the same throughout
cannot see individual parts
ex. milk, tea (colloids, solutions)
Heterogeneous
larger parts can be seen
different parts can be seen
ex. Snow globe (suspensions)

7. Ways to Separate Mixtures
Mixtures may be separated fairly easily
even hand-picked apart
Evaporation
liquid to gas leaves solids behind
such as evaporating water from salt water solutions which allows salt to form crystals
Distillation
boiling to separate liquids
all liquids have different boiling points
collect vapors of each substance

8. Ways to Separate Mixtures (cont.)
Centrifuge
separates substances based on density
the more dense substance will be pulled to the side of the spinning container because of gravity
Magnetism
metals will separate from non-metals
Filtration
smaller particles will pass through filters while larger particles stay behind

9. Examples Chart Gas in Gas Air (nitrogen, oxygen, etc.) Gas in Liquid
Soda
Liquid in Liquid
Oil and vinegar salad dressing
Solid in Liquid
Sugar in Kool-Aid, salt water
Solid in solid
Trail mix, salad, concrete, alloys

10. Summary Application Which diagram represents a mixture? Why?
What are the other two?
Why do we call the other two “pure substances”?