# What is void ratio?

Void ratio (e) is defined as ratio of the volume of voids to the volume of solids.

$$e=\frac{V_v}{V_s}$$

where :$$V_v$$ is volume of void, and $$V_s$$ is volume of solids.

Range of $$e$$ : This can be easily visualized that volume of voids can not be zero. It can go up to any limit. Hence, the range of voids ratio of is $$e>0$$.

In nature even though the coarse grained soil has large size voids. The fine grained soil has higher void ratio than the coarse grained soil (see Fig 2).

Reason behind this is, although fine grained particle has small voids. The surface area of particle increases. Hence voids also increase. On other hand surface area of coarser particle is less. Which means lesser void volume.