From a database of frequently asked questions from the Measurement section of General Chemistry Online. In the movie Raiders Of the Lost Ark Jones replaces a golden statue with a bag of sand. I know that sand does not have the same density as gold, so a bag of sand the same size as the statue would not weigh the same. He can't remove it, and their is no way to put it in water and figure the weight by water displacement. I am stumped as to how he could have been able to guess the amount of sand would have been required so it would have appeared that the Golden statue was still in place.
Any help is appreciated.
If he didn't know the volume of the statue in advance he'd have to guess. In the movie, he hesitates, removes some sand from the bag, and then swaps it with the statue. But he doesn't get it right, because the trap is sprung. It looks to me like the sand bag is close in volume to the statue. As you've pointed out, the density of sand is quite different from the density of gold.