Any variant of a "surprising" logic puzzle forces it to latch onto the surprising answer. Like whether two pounds of iron weighs more than one pound of feathers. Or any objects. It "expects" the twist, and always answers accordingly. It does so even if you change up the objects to be less tricky.

> Which is heavier, a pound of marbles or two pounds of corn?

Both weigh the same amount, which is a total of two pounds. This might seem counterintuitive at first, but it's important to remember that the pound is a unit of weight or mass, and it always refers to the same amount regardless of what is being weighed. In this case, one pound of marbles plus two pounds of corn equals a total of three pounds, whereas two pounds of corn plus one pound of marbles also equals a total of three pounds. Therefore, both weigh the same amount of two pounds.