How did Archimedes figure out that the King was cheated with silver instead of gold?

Archimedes discovered the King was cheated by using the principle of buoyancy. He noticed that when he submerged an object in water, it displaced a volume of water equal to its own volume. By comparing the displacement of water from the crown with that of a pure gold object of the same weight, he was able to determine that the crown contained less gold and more silver, indicating it had been adulterated. This realization famously led to his exclamation, "Eureka!"