Question

the sand castle in the image below illustrates the importance of what property in enhancing slope stability due to maximum cohesiveness? ○ electrical attraction between sand grains ○ water lubricating saturated sand grains ○ surface tension binding damp sand grains ○ friction between dry sand grains

Explanation:

• Electrical attraction between sand grains is not the main factor for the cohesiveness in sand - castle building.
• Water lubricating saturated sand grains would reduce cohesion (as in quick - sand like situations, high water content reduces the ability to hold shape).
• Friction between dry sand grains is important for some stability but not for the maximum cohesiveness that allows for the detailed shape of a sand - castle.
• Surface tension in damp sand (where there is just the right amount of water) acts like a "glue" between sand grains. The water forms menisci (curved surfaces) between adjacent sand grains, and the surface tension of water pulls the grains together, enhancing cohesiveness and slope stability to build structures like sand - castles.

Answer:

surface tension binding damp sand grains