1) Colloids are heterogeneous mixtures where one substance is dispersed evenly throughout another. They can exist as solid aerosols, foams, emulsions, sols, or solid foams. 2) Colloids exhibit unique optical properties like the Tyndall effect where light is scattered by colloidal particles. They also display random Brownian motion from bombardment by the dispersion medium. 3) Colloids can be classified and prepared through various processes like condensation, dispersion, or using emulsifying agents. Their stability is important and they may undergo destabilization through phenomena like sedimentation or flocculation.

1. COLLOIDS
Renz Cabiling
Bisquera
III – Kindness

2. Lucretius says…..
“Observe what happens when sunbeams are
admitted into a building and shed light on its
shadowy places. You will see a multitude of
tiny particles mingling in a multitude of ways
in the empty space… They all derive the
restlessness from the atoms. It originates with
the atoms, which move of themselves”

3. Between Suspension & Colloid
• Suspension
 Homogeneous Mixture
• Colloid
 Heterogeneous Mixture

4. Destabilisation Phenomena of a
Dispersion

5. Migration phenomena whereby the difference
in density between the continuous and
dispersed phase leads to gravitational phase
separation. In the case of
suspensions sedimentation occurs as the
dispersed phase is denser than the continuous
whereby the suspended particles join together
and increase in size. Below are the two types
of this phenomenon, reversibly and
flocculation.

6. CLASSIFICATION AND PREPARATION OF
COLLOIDS
COLLOIS TYPE DIPERSING DISPERSED EXAMPLE
MEDUIM SUBSTANCE
LIQUID AEROSOL LIQUID GAS FOG, HAIR SPRAY,
CLOUD
SOLID AEROSOL SOLID GAS SMOKE, DUST IN
AIR
FOAM GAS LIQUID WHIPPED CREAM,
BEATEN EGG
EMULSION LIQUID LIQUID WHITE, MIL,
MAYONAISE
SOL SOLID LIQUID PAINT, STARCH
MIXTURE
SOLID FOAM GAS SOLID MARSHMALOOW
SOLID EMULSION SOLID SOILD OPAL

7. CLASSIFICATION AND
PREPARATION OF COLLOIDS
• Condensation
It is the process of making particles of
atom/ion/molecular size unite to form particles
of colloidal size.
• Dispersion
It is a process of breaking down large particles
to colloidal size.

8. CLASSIFICATION AND
PREPARATION OF COLLOIDS
• Emulsifying Agent
Stabilizes an emulsion so that it does not
separate into its component.

9. Tyndall Effect
 also known as Tyndall scattering is light
scattering by particles in a colloid or particles in a
fine suspension. It is named after the 19th century
physicist John Tyndall. It is similar to Rayleigh
scattering, in that the intensity of the scattered
light depends on the fourth power of the
frequency, so blue light is scattered much more
strongly than red light. An example in everyday
life is the blue color sometimes seen in the smoke
emitted by motorcycles particularly two
stroke machines where the burnt engine oil
provides the particles.

10. Example of TYNDALL EFFECT

11. BROWNIAN MOVEMENT

12. BROWNIAN MOVEMENT
• If a colloid is viewed in a special
microscope, you will see particles moving in
erratic, haphazard motion.
• Brownian Movement is due to the constant
bombardment of the dispersed particles by rhe
dispersion medium.

13. ELECTROPHORESIS
• A process whereby the changed protein
particles migrate at varying rates to electrodes
of opposite charge.

14. DIALYSIS and HEMODIALYSIS
• Dialysis
Process of separating solute particles from
colloidal particles by means of a semi
permeable membrane.

15. DIALYSIS and HEMODIALYSIS
• Hemodialysis
A method that is used to achieve the
extracorporeal removal of waste products such
as Creatinine and urea and free water from
the blood when the kidneys are in a state
of renal failure.

16. HEMODIALYSIS in Progress