No, dry ice doesn't melt.
Understanding Dry Ice Sublimation
Dry ice, which is solid carbon dioxide (CO₂), undergoes a unique process called sublimation. This means it transitions directly from a solid state to a gaseous state without ever becoming a liquid. This is unlike regular water ice, which melts into liquid water before potentially evaporating.
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Key Difference: Regular ice melts at 32°F (0°C), forming liquid water. Dry ice, significantly colder at -109°F (-78°C), sublimates directly into carbon dioxide gas.
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The Sublimation Process: As dry ice warms, the CO₂ molecules gain enough energy to break free from their solid structure and escape as gas. This is why you see a "fog" or mist around dry ice – that's the CO₂ gas interacting with the moisture in the air.
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Practical Implications: This property makes dry ice useful for various applications, including:
- Cooling agents for transporting perishable goods.
- Creating special effects in theater and film (fog).
- Cleaning industrial equipment through dry ice blasting.
The provided reference explicitly states: "Unlike regular ice, dry ice doesn't melt into a liquid as it warms up. Instead, it converts directly back into its gaseous form in a process known as sublimation." This highlights the fundamental difference between the behavior of dry ice and regular water ice.
