Vegetable Oils - Emulsions.
Vegetable oils do not
dissolve in water.
Oil will float on top
of water because it is less dense
but tiny little drops (droplets)
of oil can be dispersed
in water
to form a mixture
called an emulsion.
An emulsion is thicker
(has a higher viscosity)
than either oil or water.
Examples of emulsions in food
are ice cream, milk
and salad dressings.
Emulsions are also used to make cosmetics
and paints.
An emulsion can be
made just by shaking oil
and water together.
Shaking the two together vigorously
breaks up the oil into
droplets
and the droplets become scattered (dispersed)
throughout the water.
When you stop shaking,
the oil and water will
separate in a little time
and the oil will float
back up to the surface of the water.
You can make the oil droplets stay
in the water for a longer
time
(called making the emulsion more stable)
by using an emulsifier.
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