Ask A Scientist© Chemistry Archive

name         Suzanne T.
status       other
age          30s

Question -   I have heard the polystyrene foam and marshmallows share the
same molecular structure.  Then I heard that was not true.  What are
their similarities and differences?
Are there any other common household items that are very similar or one
element different?
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Suzanne,

Polystyrene foam and marshmallows are the same to the extent that they are both
foams of organic compounds. Polystyrene foam is made of styrene -- a compound of
carbon and hydrogen. Marshmallows are made of sugar -- a compound of carbon,
hydrogen, and oxygen. The former is indigestible, the latter goes well with
campfires and good friends.

Window glass and the hard sugary stuff between the peanuts in peanut brittle
are both considered to be super-cooled liquids. Salt, NaCL, and an active
ingredient, NaOCl, in some chlorine bleaches. differ by a single oxygen
atom. Water is H2O and hydrogen peroxide is H2O2. Oxygen is O2 and ozone is
O3. One could go on and on.

Regards,
ProfHoff
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The closest similarity between polystyrene foam and marshmallows is that they are
both foams, that is, pockets of gas trapped inside liquid or solid
membranes.  The chemical structure of the two materials are similar only in
that they both contain carbon and hydrogen.  Polystyrene foam is actually
polystyrene blown with a variety of gases, and marshmallows are a foam of
gelatin, sugar, and air.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois
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Polystyrene foam [foamed styrene] and marshmallows [foamed sugar+??] have a
similar gross structure, that is they are closed-cell foams [unconnected
micro-bubbles] but they are not the same chemical.

Ivory soap [that floats in water] is also a closed-cell foam of soap. It
contains about 0.5% air. Beaten egg whites are a foam. Milk shakes served at
most fast-food restaurants are foams. That's why they feel so light. A
bubble bath is a foam.

Vince Calder
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