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 "Dry Ice," the trademark name for solid carbon dioxide, reaches its solid state
when cooled liquid carbon dioxide is put under pressure.
Scientists successfully produced the snowy, white solid, which
produced temperatures dipping as low as 109 degrees Fahrenheit, and
envisioned dozens of practical uses for "Dry Ice." Unfortunately,
they had yet to discover how to keep this solid from melting back
into its original liquid state.
Fortunately, the solution to the scientists' dilemma, which
possibly dawned on them over cocktails at happy hour, lay in the
fact that when "Dry Ice" mixes with liquids having very low freezing
temperatures, for example alcohol, instead of melting, the solid
turns into gas. Because the gas escapes into the air, it packs more
refrigeration power than an identical amount of ice made from
water.
The primary use for "Dry Ice," both then and today, is to keep
perishables fresh, especially during
shipment. Solid carbon dioxide made its debut as the packing
material of choice for ice cream.
Today, products such as fish and meat can be shipped thousands of
miles, and arrive at their destinations. Eggs can remain fresh
indefinitely if refrigerated with solid carbon dioxide, as the
primary reason they grow stale is the escape of carbon dioxide from
tiny pores in their shells. When enveloped by the vapor from the gas
solid carbon dioxide emits, the escape of carbon dioxide from their
shells is cancelled out.
Even florists take advantage of the preservative property of "Dry
Ice," and can prevent flower buds from opening for up to three days
by placing them in a solid carbon dioxide atmosphere. Essentially,
"Dry Ice" temporarily freezes the aging process to suit our
purposes.
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note:
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solid carbon dioxide:
固体二氧化碳
perishable: 容易腐烂的东西
cancel out: 抵偿 | |
