If ya’ll like a-splashin and a-paddlin at the seaside, ya know that wet sand is a different animal to dry sand. Nobody builds sandcastles outta dry sand, right?
Axel “Ice Cream” Fingerle and his buddy Stephan at the Max-Planck Institute for Dynamics and Self Organization in Germany say they know why.
“The reason…is that…small liquid capillary bridges form between
adjacent grains, exerting an attractive force upon
them by means of the surface tension of the liquids”
In other words, wet sand sticks together better. Now ya know!
Ref: arxiv.org/abs/0708.2597: Mechanisms of Dissipation in Wet Granular Matter