Examples of discovering truth from ordinary things

In the eyes of ordinary people, Archimedes is a "freak". In the words of Plutarch, a Roman historian, "He seems to be an enchanted man. He doesn't care about food or his body." Sometimes, the rice is put on the table and asked to eat, but he doesn't seem to hear it. He is still drawing his geometry in the ashes of the brazier. His wife should look after him at all times. For example, when he rubbed his body with oil, he just sat and oiled himself and forgot what he had done. His wife is more afraid of sending him to the bathhouse to take a bath. The joke was caused by a new crown of the king.

Not long ago, the king asked a craftsman to build him a golden crown. The king gave the craftsman the gold he needed. The craftsman's craft is very clever, and the crown produced is exquisite and unique, and the weight is as heavy as the gold given by the king at the beginning. However, someone reported to the king: "When making the crown, the craftsman swallowed some gold privately and mixed the same weight of silver." Hearing this, the king became suspicious, so he called Archimedes and asked him to try to determine whether the gold crown was mixed with silver and whether the craftsmen kept the gold for themselves. Archimedes was stumped this time. When he got home, he thought hard for a long time and couldn't find a way. I can't eat, sleep or take a shower every day, as if I were possessed.

One day, the king sent someone to urge him to report to the palace. His wife saw that he was too dirty and forced him to take a bath. When he was taking a bath in the bathhouse, he was still thinking about weighing the crown. Suddenly, he noticed that some water overflowed from the side of the bathtub when his body sank into it. At the same time, he felt that the deeper he went into the water, the lighter he was. So, he immediately jumped out of the bathtub, forgot to wear clothes and ran to the street of the crowd. He ran and shouted, "I found it, I found it, and the solution to the crown was found!" " "

After he entered the palace, he said to the king, "Please allow me to do an experiment, and then I can report the result to you." The king agreed. Archimedes put the gold, a piece of silver and the crown, which are as heavy as the crown, in the basin one by one, and saw that the gold nugget discharged less water than the silver nugget, while the crown discharged more water than the gold nugget.

Archimedes said to the king, "The crown is mixed with silver!" " "The king looked at the experiment and didn't understand. Let Archimedes explain. Archimedes said, "One kilogram of iron is bigger than one kilogram of wood. If you put them in water separately, the big wood will discharge more water than the small iron. I apply this principle to gold, silver and crowns. Because the density of gold is high and the density of silver is low, if gold and silver are equally heavy, the volume of silver must be greater than that of gold. Gold nuggets and silver nuggets with the same weight are put into water, and the amount of water discharged by gold nuggets is less than that of silver nuggets. The experiment just now shows that the crown discharges more water than the gold nugget, indicating that the density of the crown is smaller than that of the gold nugget, which proves that the crown is not made of pure gold. " Archimedes' methodical narration persuaded the king. The experimental results prove that the craftsman put the gold in his pocket.

This experiment of Archimedes is the embryonic form of "hydrostatics". However, he did not stop there and continued to study the floating body problem in depth. Results Archimedes principle, an important principle in natural science, was discovered. That is, when an object is immersed in a liquid, the volume of the displaced liquid is equal to the volume in which the object is immersed; Keep the buoyancy of the floating body equal to the weight of the liquid discharged by the floating body.