干冰是固態(tài)的二氧化碳，由于干冰的溫度非常低，溫度為攝氏負(fù)78.5度，因此經(jīng)常用于保持物體冷凍或低溫狀態(tài)。因?yàn)樗诨瘯r(shí)是由固態(tài)直接升華為氣態(tài)，不會(huì)產(chǎn)生任何水或液體，我們稱(chēng)它做“干冰”。

"Dry Ice," the trademark name forsolid 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 keepperishablesfresh, 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 iscancelled 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.

solid carbon dioxide: 固體二氧化碳

perishable: 容易腐爛的東西

cancel out: 抵償

（來(lái)源：coolquiz.com 英語(yǔ)點(diǎn)津 Annabel 編輯）

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