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- [Instructor] Think about
all the thousands of books

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and poems and articles and
dictionaries and encyclopedias

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and textbooks and so much more.

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All those English writings are
fundamentally made of what?

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26 letters

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and yeah, some spaces, but that's it.

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These 26 letters forms the building block

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of almost every single thing,

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all the uncountable words and
sentences that you can make.

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Now, guess what?

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Turns out our nature is similar.

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Almost everything that
you can touch and taste

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and smell and feel around you,

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from the germs to microbes

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to stuff like cats and dogs

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to oceans and mountains
and even planets and stars.

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Turns out all of these are also made

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from just a few building
blocks, about a hundred of them.

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Each square over here
represents a building block,

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and we'll talk a little bit

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about how we arrange them and stuff,

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but these building blocks
are called the elements,

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and that's what we're gonna
talk about in this video.

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So let's do that.

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First of all, these elements,

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the building blocks are
also called pure substances.

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And like I said earlier,

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they make up almost all
the matter around us.

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For example, if you consider water,

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it's made of two kinds of
elements: hydrogen and oxygen.

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And consider any living
being like yourself,

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that you are mostly made of six elements:

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oxygen, carbon, hydrogen,

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nitrogen, calcium and phosphorus.

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I mean, there are other elements,

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but these mostly make it up.

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And just to give you another example,

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if you consider any rock,

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and they're mostly made of five elements:

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silicon, oxygen, aluminium,
magnesium, and iron.

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Don't worry about remembering the names

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of these elements for now.

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What's important, and I keep repeating

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because it's so important,

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is that almost all the matter
in the universe is made

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from these elements.

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So to study matter, we need
to study these elements.

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So let's do that.

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We arrange these elements
in this particular form,

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and we call this the periodic table.

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It might seem daunting at first,
but let's look at it, okay?

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So first of all, you can see

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that each element gets
a square and a number.

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So element number one is hydrogen.

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Element number two is over here, helium.

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Element number three is lithium.

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Element number four is beryllium,
and so on and so forth.

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What we wanna notice over here is

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that each element has a symbol,
kind of an abbreviation.

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Now, for some elements,

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that's basically the
first letter of the word.

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H for hydrogen,

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B for boron,

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C for carbon,

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N for nitrogen, and so on and so forth.

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And notice we always use capital letters.

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But what about other elements which start

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with the same letter, for example, helium?

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How do we ensure we don't
confuse it with hydrogen?

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Well, we use first two letters, so He.

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Similarly for calcium,

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to make sure we don't
confuse it with carbon,

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we use the first two letters,
Ca and so on and so forth.

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But what's important again over here is

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to notice how we write it.

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When we have the two letters,

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the first letter is capital over here,

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the second letter is small.

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So we'll never write helium
this way where both are capital

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and we'll never write this
way where both are small.

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We'll always write as
first letter capital,

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second letter small, and
that's always the case.

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Alright, these make sense,
but what about sodium?

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Sodium is Na, what's going on over here?

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And then there's more such stuff.

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So for example, gold is Au.

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Tungsten, which is used in the
filament of our bulbs, is W?

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And lead is Pb.

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What's going on over here?

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Well, humanity has known
about these elements

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for a long time now,

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and some of these symbols
are taken from the old names

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from different languages
like Greek, Latin,

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Arabic, German, and so on.

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For example, Na stands for natrium,

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Latin word for sodium.

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Au comes from aurum.

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Pb comes from plumbum,
the Latin word for lead.

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Fun fact earlier pipes

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in the Roman Empire were made from lead,

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and therefore people who used

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to fix those pipes are called plumbers,

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and the name is stuck today.

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And W comes from the German, wolfram.

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Now again, you might be thinking,

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"Oh my God, how am I supposed
to remember all of this?"

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Don't worry, we don't have to do that.

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As we start talking about
some of the common elements

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over and over again,

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we'll start familiarizing
ourselves with them.

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So don't worry about it.

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So in summary, all the
matter that you see,

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almost everything in the universe,

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is made of a few, about
a hundred elements,

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which we also call the pure substances.

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They're arranged this way

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in what we call the periodic table.

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And just like how learning
the English language

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is basically figuring out

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how we can combine these different letters

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to form very interesting
words and sentences.

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The trick to learning about matter

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is learning how we can combine
these different elements

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to form interesting new things.

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It's kind of like legos,

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the plastic building blocks
we used to play with before.

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Well, imagine we had a hundred different

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kinds of legos with us.

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Then by combining them in
different combinations,

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you can build up almost anything you want.

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And now you can imagine some

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of these lego structures
are like mountains

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and others are like cats.

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And we can build whatever we want.

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We can let our imagination lose over here,

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which is pretty awesome.

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But if you break them all
down into their basic pieces,

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you get back your elements.