Why does dry sand weigh more than wet sand?

Anyone who has dug a shovelful of wet sand and a shovelful of dry sand will tell you that the wet sand is quite a bit heavier than the dry sand.

Dry sand is composed of individual particles with air in the spaces between grains. When you add water to a bucket of dry sand, the water replaces the air. Although the bucket is already full of sand, you can pour in quite a bit of water, adding that much more weight.

If you have a choice of which bucket to carry, pick the bucket of dry sand every time!