Explaining Camphor's Direct Conversion to Gas

The question describes a specific physical process where a substance, in this case, camphor, transforms directly from a solid state into a gaseous state when heated, without undergoing a melting phase (solid to liquid). We need to identify the scientific term for this phenomenon.

Understanding the Phenomenon: Sublimation

The process described is known as Sublimation. This occurs when a solid changes directly into a gas or vapor without first becoming a liquid. Many substances exhibit sublimation under specific conditions, and camphor is a common example readily observed in daily life. When solid camphor is heated, its molecules gain enough energy to overcome the forces holding them in the solid structure, allowing them to escape directly into the gaseous phase.

Key characteristics of sublimation include:

• Direct transition from solid to gas.
• Bypasses the liquid phase entirely.
• Often observed when heating solids like camphor, iodine, or dry ice (solid carbon dioxide).

Analyzing Other Phase Change Options

Let's look at why the other options are not correct for the described scenario:

• Fusion: This term refers to the process of melting, where a substance changes from a solid state to a liquid state due to an increase in temperature. This is the opposite of what happens with camphor in the question, as it skips the liquid phase.
• Evaporation: This is the process where a liquid changes into a gas or vapor. Since camphor directly changes from solid to gas without becoming liquid, evaporation does not describe this specific transformation.
• Conversion: This is a very general term that means changing from one form or state to another. While sublimation is a type of conversion, it is not specific enough to describe the direct solid-to-gas transition. The question asks for the specific term for this particular phenomenon.

Therefore, the direct conversion of camphor from solid to gas upon heating is accurately termed Sublimation.