Which statement is true about density definitions: Wet Density includes water?

• A. Wet Density
• B. Dry Density
• C. Bulk Density
• D. Apparent Density

Answer: (A)

In soils, density definitions change with moisture state. Wet density is defined as the mass of the soil plus its water per unit total volume, so water is included in the mass. Put succinctly, wet density = (mass of solids + mass of water) / volume. This means water contributes to the density value.

You can relate it to dry density, which is the mass of solids per unit volume (water excluded): wet density = dry density × (1 + w), where w is the moisture content (water mass divided by dry solids mass). This relationship helps explain why wetter material is denser.

Other density terms refer to different ways of accounting for moisture or voids, but the key point for the statement is that wet density inherently includes water in its mass.