Grade 7 Science

1
Grade 7 Science

• Separating Solutions

2
Student Activity

• Discuss with a partner how you would separate the
  following mixtures
• Salt water
• Muddy water
• Nuts and bolts

3

• Iron filings and sand
• Vegetable oil and sand
• Vegetable oil and water
• Salt and pepper
• Be prepared to defend your answers!

4
Discussion Question

• Are the components you have separated still
  mixtures, or are they pure? Why or why not?

5
Separation Techniques

• Mechanical Sorting
• Used to separate the parts of a mixture based on
  properties such as particle size.
• Examples floatation magnetism

6
magnetism
floatation
7
Filtration

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

8
Oil filter
Coffee filter
Colander
Furnace filter
9
Evaporation

• Change of state from a liquid to a gas.
• Used to recover a solid solute from a solution.

10
(No Transcript)
11
Distillation

• Uses two changes of state evaporation and
  condensation.
• It allows you to recover BOTH the solute and
  solvent from a solution.

12
Condensation
Evaporation
13
Paper Chromatography

• Used to separate the colored substances in a
  mixture such as ink.
• Used to separate the solvents in a mixture.

14
(No Transcript)
15
Separation Techniques in the Home

• Colanders
• Clothes dryers
• Window screens
• Coffee percolators
• Salad spinners
• Any others?