Which state is almost incompressible under ordinary conditions?

• A. Highly compressible
• B. Moderately compressible
• C. Almost incompressible
• D. Completely incompressible

Answer: (C)

Compressibility depends on how tightly particles are held together and how much space there is between them. In solids, particles are tightly packed and held in fixed positions by strong forces, so there isn’t much room to move closer when pressure is applied. That makes the volume change extremely small, so solids are almost incompressible under ordinary conditions. Describing a state as almost incompressible captures this behavior, acknowledging only a tiny, real amount of compression that could occur. Gases are highly compressible because their particles are far apart and easily pushed closer together, while liquids are also nearly incompressible but still show a small amount of compression under pressure. No real material is perfectly incompressible, which is why the idea of complete incompressibility isn’t accurate.