ChemMatters | FEBRUARY/MARCH 2018 7
Rohrig, B. 39 Dazzling Experiments with Dry Ice, FizzBang Science: Plain City, Ohio, 2003.
Ackerman, K. History of Dry Ice. Dry Ice Info.com (last revised Feb 21, 2013): http://dryiceinfo.com/history.htm.
The History of Dry Ice. Dry Ice Corp.com: http://www.dryicecorp.com/many-uses-of-dry-ice/the-history-of-dry-ice/.
Bryk, N. E. V. How Products Are Made: Dry Ice. Made How.com: http://www.madehow.com/Volume-7/
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Brian Rohrig is a science writer who lives in Columbus, Ohio. His most recent ChemMatters article, “The
Write Stuff: The Fascinating Chemistry of Pencils,” appeared in the December 2017/January 2018 issue.
These dry ice flakes have a somewhat fluffy,
airy texture. To make a block of dry ice, a
hydraulic press exerts up to 60 tons of pressure on the emerging dry ice. A dense hard
block of dry ice can be made very quickly—a
50-kilogram block can be made in less than 2
The relatively high density of dry ice and
its sublimating vapors leads to an interesting
phenomena. Unlike regular ice that
floats, dry ice has a density of
1. 5 grams per milliliter, which
means it will sink in water. When
placed in water, the resulting CO2-saturated
fog is denser than air. The high density of CO2
gas makes it an excellent fire extinguisher; the
CO2 sinks to the bottom and displaces the surrounding air, depriving the fire of oxygen.
Although it was discovered in 1835, it
took more than 60 years for anyone to do
something productive with dry ice. In 1897,
a British doctor obtained a patent to use dry
ice to carbonate beverages. In 1925, the
Dry Ice Corporation was created. It used pressurized CO2 in
fire extinguishers and dry ice for
shipping ice cream—still in use
today. Although the term “dry ice” started
out as a trade name, it is now adopted as the
common name of the substance.
Today, dry ice is used for a variety of pur-
poses. One of its most common uses is to
create special effects, such as making fog in
theatrical stage productions. Since the fog
given off is imbued with invisible CO2 vapor,
As the skin becomes cold, the body
constricts blood flow to these areas in an
attempt to preserve core body temperature.
This lack of blood flow leads to tissue death,
which occurs in severe cases of frostbite.
Always handle dry ice with care and be sure
to cover all of the surfaces of your body that
could be exposed—wear protective clothing
and thermal gloves.
Dry ice should never be used in an
enclosed area without adequate ventilation, as
inhalation of excess CO2 can be deadly. If too
much CO2 builds up in your blood, the pH will
become too acidic, which can be fatal. Breathing in CO2 also causes asphyxia because your
body is deprived of oxygen.
Finally, never store dry ice in an enclosed
container. As it undergoes sublimation, CO2
gas pressure builds up, and since gas is
matter, it needs somewhere to go. It can be
safely transported in a cardboard box, which
is porous and allows the sublimating CO2
gas to escape. If placed in a cooler, it
is important that the
lid not be
In all of
are not likely
to come across
a substance as
nating as dry ice. It
is dangerous, which
is part of its allure.
But if proper safety precautions are
followed, dry ice can be the source of count-
less hours of intriguing fun and experimenta-
tion—putting the magic of chemistry on full
Thermal gloves should be used to handle dry ice
to prevent frostbite.
it will sink downward, adding to its enchantment. Another common use of dry ice is in
shipping frozen foods. If you have ever had
steaks or other frozen foods delivered to
your home, they may have been packed
in dry ice. The neighborhood ice cream
vendor still uses dry ice to keep the frozen treats cold.
Remember three very
important safety precautions
when handling dry ice: 1) don’t
touch it, 2) don’t inhale it, and 3)
don’t put it in an enclosed
container. If dry ice contacts
skin for more than a few
seconds, frostbite can occur.