Archimedes of Syracuse He was a mathematician, physicist, engineer, inventor and astronomer. He is considered one of the most important scientists of classical antiquity, we owe him inventions such as the Archimedean screw (machine used to raise water), the compound pulley, the lathe, the toothed wheel, the law of the lever ("give me a point of support and I will move the world»), war machines… and, above all, the principle of Archimedes (hydrostatics). And it is precisely this principle that demonstrates that it could be considered the pattern of experts.
Hiero II , king of Syracuse and relative of Archimedes, ordered a gold crown from a goldsmith. When the king received his crown, something made him doubt the "purity" of the gold used (he thought that part of the gold given for the work could have been replaced by silver or copper) and he asked Archimedes to determine if the material used was gold. pure (what today we would call an expert opinion ). Archimedes was used to this type of "commissions"... he would have the solution if he could determine the volume of the crown. If the goldsmith had used silver or copper (lighter than gold) the volume of the crown would be greater than the equivalent weight of gold. How to determine the volume of the crown?
After thinking about it a lot, he decided to take a break and take a bath. He was so into it that he didn't realize he had filled the tub to the brim and when he got some of the water in it came out... Eureka! shouted the scientist, he already had the solution:
the volume of any body submerged in water was equal to the volume of displaced water (plus or minus).
So, he lowered the crown into the water and measured the volume of displaced water and did the same with an equal weight of pure gold; in this case the volume of water displaced was less than with the crown. Therefore, the volume of the crown was greater... the goldsmith had mixed the gold with other lighter metals... Arquimedes' expertise led to the death of the goldsmith.
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