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  • Our Earth is a collection of puzzle pieces that make up the universe.

  • In the vast darkness of space,

  • the universe is lit by stars,

  • which could one day become a supernova

  • and create all the puzzle pieces that we know today

  • as the elements.

  • All elements were formed and released

  • into space by exploding stars.

  • For centuries, humans have tried to discover

  • what makes up the world around them.

  • Little did they know that all the pieces they needed

  • were right under their noses.

  • The discovery of these pieces revolutionized

  • our understanding of the world

  • and allowed for the creation of what might be

  • the greatest gift to science:

  • the periodic table.

  • So, where are these elements,

  • and how do we find a means to order them?

  • Well, believe it or not,

  • ancient civilizations were very much aware

  • of many elements around them,

  • but they did not identify them as the pieces of our universe.

  • Elements like gold, silver, and copper

  • were easily spotted by ancient cultures,

  • and were used for multiple purposes like jewelry and tools.

  • Why were these elements spotted so easily?

  • Think of the periodic table as a puzzle.

  • The corner pieces are edges of a puzzle,

  • are generally the easiest to find and place

  • because they stand out with their smooth edges,

  • and clearly don't interlock with other puzzle pieces.

  • Like puzzle pieces, elements can be choosy on who they interact with.

  • Some like to react with other elements,

  • while others do not.

  • The elements that do not interact with other elements are easy to pin-point,

  • while the ones who like to interact with others are difficult to find.

  • Gold, silver, and copper are some of the choosier elements

  • so we can find them easier.

  • So let's fast forward to the late 1600's

  • where Hennig Brand, a German alchemist,

  • was busy working in his laboratory.

  • Like many other alchemists of his time,

  • Brand was trying to extract gold from the human body.

  • Brand hit upon what he thought was the most obvious answer to his problem:

  • urine.

  • Urine is gold in coloration and could perhaps have gold in it.

  • So, Brand collected as much urine as he possibly could,

  • much of it being his own,

  • then he decided to boil it down in hopes of obtaining gold.

  • So Brand boiled his, well, urine,

  • down until he collected a paste

  • and heated the paste to a very high temperature.

  • Eventually smoke appeared

  • and the material burned brightly and violently.

  • Brand had unknowingly isolated phosphorous from his urine.

  • It was the first time anyone had discovered an element,

  • but he didn't really understand what he had done.

  • At the time of Brand, the concept of element had not been discovered.

  • Instead ancient Greek principles of objects being composed of

  • earth,

  • water,

  • air,

  • and fire

  • were predominant.

  • It wasn't until the work of Antoine Lavoisier,

  • who is now known as the father of chemistry,

  • that science defined what an element was.

  • Lavoisier defined an element as a substance

  • that cannot be broken down by existing chemical means.

  • Lavoisier created a list of the known elements of his time

  • and tried to put the elements in some sort of order

  • in which they could be classified,

  • such as gases or metals.

  • He was the first one to try to put the puzzle together.

  • This was just the beginning of a means

  • to organize the known elements of his time.

  • Many other chemists then came along to make the puzzle clearer.

  • One of them, John Dalton, weighed the elements

  • and arranged the puzzle by weight.

  • German chemist Wolfgangbereiner later combined elements

  • to see how they reacted with one another.

  • What he found was that certain elements shared similar properties and reactions.

  • For example, when pure lithium, sodium, and potassium

  • are exposed to water,

  • they will react violently

  • and skid across the surface of the water with sparks.

  • The scientists then realized that these similiarities

  • are no coincidence:

  • elements belong to families that share similar properties.

  • But the chemist who finally put the puzzle together is Dmitri Mendeleev.

  • He created cards of each known element and tried to order them

  • based on atomic weight and their known properties.

  • The story is that he stayed up 3 days and 3 nights,

  • and he finally fell into a deep sleep

  • and he dreamed about a table to order the elements.

  • Mendeleev was not only able to create the periodic table,

  • but he was able to predict elements that were not yet discovered.

  • The puzzle of the periodic table of the elements was solved.

Our Earth is a collection of puzzle pieces that make up the universe.

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TED-ED】周期表の謎を解く - エリック・ロサード (【TED-Ed】Solving the puzzle of the periodic table - Eric Rosado)

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    VoiceTube に公開 2021 年 01 月 14 日
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