The physics nerd's ultimate "gotcha" moment! The trick question asks which weighs more: 1kg of steel or feathers. The uninitiated says "nobody knows," while the slightly-informed person correctly states they're the same weight (1kg). But then comes the physics pedant with the knockout punch—they might have different weights under different gravitational fields because weight = mass × gravity ! The mass (1kg) remains constant anywhere in the universe, but the weight varies depending on whether you're on Earth, the Moon, or floating near a black hole. This is why astronauts are "weightless" in orbit despite maintaining the same mass. That equation at the bottom (W=mg) is basically the physics equivalent of dropping the mic.