Here's a breakdown:

* Solid: In a solid, particles are tightly packed together in a fixed, rigid structure.

* Gas: In a gas, particles are widely spaced and move freely.

Sublimation is the process where a solid directly changes into a gas without passing through the liquid state. This occurs when the solid absorbs enough energy (usually heat) to overcome the forces holding its particles together.

Examples of sublimation:

* Dry ice (solid carbon dioxide) sublimes into carbon dioxide gas at room temperature.

* Mothballs (naphthalene) gradually sublimate into a vapor that repels moths.

* Frozen water (ice) can sublimate directly into water vapor in cold, dry conditions.

Let me know if you have more questions!