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  • Atoms are ridiculous and unbelievably small.

  • A single human hair is about as thick as

  • 500,000 carbon atoms stacked over each other.

  • Look at your fist, it contains trillions and trillions of atoms.

  • If one atom in it were about as big as a marble, how big would your fist be?

  • Wellabout the size of Earth. Hmstill hard to imagine?

  • Let’s try something different

  • Look at your little finger.

  • Imagine that its tip is as big as the room youre sitting in right now.

  • Now fill the room with grains of rice.

  • One rice corn represents one cell of your fingertip.

  • Now let’s zoom in on the rice corn.

  • And now, one cell is as big as the room youre in right now.

  • Let’s fill it with rice again. This is about the size of a protein.

  • And now, let us fill all the empty spaces between the rice corns

  • with fine grains of sand.

  • This is roughly how small atoms are.

  • What is an atom made of?

  • Let us just pretend that atoms look like this for a minute

  • to make it easier to understand.

  • An atom consists of three elementary particles:

  • neutrons, protons and electrons.

  • Protons and neutrons bind together and form the atom core,

  • held together by the strong interaction,

  • one of the four fundamental forces in the universe.

  • They are made from quarks and held together by gluons.

  • Nobody knows exactly how small quarks are.

  • We think they might literally be points, like in geometry.

  • Try to imagine them as being zero-dimensional.

  • We suspect that quarks and electrons are

  • the most fundamental components of matter in the universe.

  • Electrons orbit the atom core. They travel at a speed of about 2,200 km/s,

  • fast enough to get around the Earth in just over 18 seconds.

  • Like quarks, we think electrons are fundamental particles.

  • 99.999999999999%

  • of an atom’s volume is just empty spaceExcept that it isn’t.

  • What we perceive as emptiness is actually a space filled by quantum fluctuations,

  • fields that have potential energy and build and dissolve spontaneously.

  • These fluctuations have a fundamental impact on how charged particles interact.

  • But that’s a topic for another video.

  • How much space do the core and electrons actually fill?

  • If you were to subtract all the spaces between the atom cores

  • from the Empire State Building, it would be about as big as a rice corn.

  • All the atoms of humanity would fit in a teaspoon.

  • There are extreme objects where states like this actually exist.

  • In a neutron star, atom cores are compacted so densely

  • that the mass of three Suns fits into an object only a few kilometers wide.

  • By the way, what do atoms look like?

  • Well, kind of like this.

  • Electrons are like a wave function and a particle at the same time.

  • We can calculate where an electron might be at any given moment in time.

  • These clouds of probability, called orbitals,

  • are where electrons might be with a certainty of 95%.

  • The probability of finding an electron approaches 0

  • the further we get away from the atom core,

  • but it actually never is zero, which means that, in theory,

  • the electron of an atom could be on the other side of the universe.

  • Okay, wait a second.

  • These strange thingies make up all the matter in the universe.

  • For many dozens of known elements,

  • you don’t need many dozens of elementary particles, just three.

  • Take one proton and one electron, and you have hydrogen.

  • Add a proton and a neutron, you have helium.

  • Add a few more, you get carbon, a few more, fluorine,

  • even more, gold, and so on.

  • And every atom of an element is the same:

  • all hydrogen atoms in the universe, for example, are the same;

  • the hydrogen in your body is exactly the same as the hydrogen in the Sun.

  • Do you feel confused right now? We certainly do!

  • Nothing on this scale of the universe makes any sense in our world,

  • and weve not even begun talking about quantum mechanics or the particle zoo,

  • which are even stranger!

  • Our model of atoms has changed a number of times since we first conceived it,

  • and the current one will certainly not be the last.

  • So let us support scientists and research

  • and wait for the next wave of mindboggling new information

  • about this strange world that is the basis for our existence.

  • Subtitles by the community

Atoms are ridiculous and unbelievably small.

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B2 UK atom rice universe electron hydrogen fundamental

How Small Is An Atom? Spoiler: Very Small.

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    羅紹桀 posted on 2015/08/19
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