ppt – Nano Ice Cream

June 27, 2012
Chris Marin
What is a liquid?
 All liquids:
 have a definite volume
 conform to the shape of container
 are not compressible
 are made up of atoms that aren’t in
fixed places
What is a solid?
 All solids:
 have a definite volume
 have a definite shape
 are made up of atoms in fixed places
What is ice cream??
 It has ice in the name, is it a solid?
 Not quite! See how it took the shape of the glass?
 Is it a liquid?
 Not unless you wait to long!
 It’s both!
 A colloid is one phase mixed into another.
 Ice cream is both a foam, emulsion, and sol!
So what is ice cream?
 In the above microscope image, A is air bubbles, C is ice
crystals, F is fat, and S is a solution of liquid.
 A big part of controlling ice cream’s texture is controlling
how much air and ice are in the colloid.
nano-ice cream
 We will be using liquid nitrogen to rapidly make ice cream
 Normally, ice cream takes hours to make, but liquid
nitrogen is extremely cold (-321 °F, or 77 K)
 The change in temperature when the liquid nitrogen is
poured in should be so rapid that the cream doesn’t have
time to change to ice
 Instead, tiny nanometer sized ice crystals should form, like
snow does on a very cold day.
 This should make our ice cream very very smooth!

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