It’s a question I sometimes remember, when doing fitness. I always wanted to wear weights on my arms or legs. But they are always filled with sand and are very bulky and weird. I am wondering, why we’re not using more dense materials? Why not metal? The weights at the gym aren’t sand.
Pretty much it. When we made some we drove to the beach and filled a bucket full of sand, took it home, ran it through a sieve.
Exploiting natural resources.