0:00:00.150,0:00:01.860
- [Instructor] Think about[br]all the thousands of books

0:00:01.860,0:00:04.680
and poems and articles and[br]dictionaries and encyclopedias

0:00:04.680,0:00:06.840
and textbooks and so much more.

0:00:06.840,0:00:11.220
All those English writings are[br]fundamentally made of what?

0:00:11.220,0:00:12.930
26 letters

0:00:12.930,0:00:15.330
and yeah, some spaces, but that's it.

0:00:15.330,0:00:17.280
These 26 letters forms the building block

0:00:17.280,0:00:18.870
of almost every single thing,

0:00:18.870,0:00:22.830
all the uncountable words and[br]sentences that you can make.

0:00:22.830,0:00:24.030
Now, guess what?

0:00:24.030,0:00:26.760
Turns out our nature is similar.

0:00:26.760,0:00:29.070
Almost everything that[br]you can touch and taste

0:00:29.070,0:00:30.390
and smell and feel around you,

0:00:30.390,0:00:32.490
from the germs to microbes

0:00:32.490,0:00:33.960
to stuff like cats and dogs

0:00:33.960,0:00:38.040
to oceans and mountains[br]and even planets and stars.

0:00:38.040,0:00:41.520
Turns out all of these are also made

0:00:41.520,0:00:45.660
from just a few building[br]blocks, about a hundred of them.

0:00:45.660,0:00:47.910
Each square over here[br]represents a building block,

0:00:47.910,0:00:48.743
and we'll talk a little bit

0:00:48.743,0:00:50.910
about how we arrange them and stuff,

0:00:50.910,0:00:54.300
but these building blocks[br]are called the elements,

0:00:54.300,0:00:56.010
and that's what we're gonna[br]talk about in this video.

0:00:56.010,0:00:57.150
So let's do that.

0:00:57.150,0:00:58.620
First of all, these elements,

0:00:58.620,0:01:01.710
the building blocks are[br]also called pure substances.

0:01:01.710,0:01:03.210
And like I said earlier,

0:01:03.210,0:01:05.550
they make up almost all[br]the matter around us.

0:01:05.550,0:01:07.500
For example, if you consider water,

0:01:07.500,0:01:11.730
it's made of two kinds of[br]elements: hydrogen and oxygen.

0:01:11.730,0:01:14.610
And consider any living[br]being like yourself,

0:01:14.610,0:01:17.910
that you are mostly made of six elements:

0:01:17.910,0:01:20.610
oxygen, carbon, hydrogen,

0:01:20.610,0:01:23.520
nitrogen, calcium and phosphorus.

0:01:23.520,0:01:25.020
I mean, there are other elements,

0:01:25.020,0:01:27.300
but these mostly make it up.

0:01:27.300,0:01:29.430
And just to give you another example,

0:01:29.430,0:01:30.990
if you consider any rock,

0:01:30.990,0:01:33.660
and they're mostly made of five elements:

0:01:33.660,0:01:38.490
silicon, oxygen, aluminium,[br]magnesium, and iron.

0:01:38.490,0:01:40.200
Don't worry about remembering the names

0:01:40.200,0:01:41.520
of these elements for now.

0:01:41.520,0:01:43.290
What's important, and I keep repeating

0:01:43.290,0:01:44.580
because it's so important,

0:01:44.580,0:01:48.510
is that almost all the matter[br]in the universe is made

0:01:48.510,0:01:50.970
from these elements.

0:01:50.970,0:01:54.870
So to study matter, we need[br]to study these elements.

0:01:54.870,0:01:56.490
So let's do that.

0:01:56.490,0:01:59.220
We arrange these elements[br]in this particular form,

0:01:59.220,0:02:01.890
and we call this the periodic table.

0:02:01.890,0:02:05.760
It might seem daunting at first,[br]but let's look at it, okay?

0:02:05.760,0:02:06.750
So first of all, you can see

0:02:06.750,0:02:09.660
that each element gets[br]a square and a number.

0:02:09.660,0:02:12.420
So element number one is hydrogen.

0:02:12.420,0:02:14.850
Element number two is over here, helium.

0:02:14.850,0:02:17.100
Element number three is lithium.

0:02:17.100,0:02:19.980
Element number four is beryllium,[br]and so on and so forth.

0:02:19.980,0:02:21.270
What we wanna notice over here is

0:02:21.270,0:02:24.630
that each element has a symbol,[br]kind of an abbreviation.

0:02:24.630,0:02:25.500
Now, for some elements,

0:02:25.500,0:02:27.630
that's basically the[br]first letter of the word.

0:02:27.630,0:02:29.040
H for hydrogen,

0:02:29.040,0:02:30.390
B for boron,

0:02:30.390,0:02:32.010
C for carbon,

0:02:32.010,0:02:34.290
N for nitrogen, and so on and so forth.

0:02:34.290,0:02:36.870
And notice we always use capital letters.

0:02:36.870,0:02:38.460
But what about other elements which start

0:02:38.460,0:02:41.160
with the same letter, for example, helium?

0:02:41.160,0:02:43.650
How do we ensure we don't[br]confuse it with hydrogen?

0:02:43.650,0:02:47.430
Well, we use first two letters, so He.

0:02:47.430,0:02:48.780
Similarly for calcium,

0:02:48.780,0:02:50.550
to make sure we don't[br]confuse it with carbon,

0:02:50.550,0:02:54.960
we use the first two letters,[br]Ca and so on and so forth.

0:02:54.960,0:02:56.640
But what's important again over here is

0:02:56.640,0:02:58.020
to notice how we write it.

0:02:58.020,0:02:59.460
When we have the two letters,

0:02:59.460,0:03:02.160
the first letter is capital over here,

0:03:02.160,0:03:03.870
the second letter is small.

0:03:03.870,0:03:06.720
So we'll never write helium[br]this way where both are capital

0:03:06.720,0:03:09.000
and we'll never write this[br]way where both are small.

0:03:09.000,0:03:10.680
We'll always write as[br]first letter capital,

0:03:10.680,0:03:13.560
second letter small, and[br]that's always the case.

0:03:13.560,0:03:17.220
Alright, these make sense,[br]but what about sodium?

0:03:17.220,0:03:19.950
Sodium is Na, what's going on over here?

0:03:19.950,0:03:21.600
And then there's more such stuff.

0:03:21.600,0:03:24.480
So for example, gold is Au.

0:03:24.480,0:03:29.190
Tungsten, which is used in the[br]filament of our bulbs, is W?

0:03:29.190,0:03:30.630
And lead is Pb.

0:03:30.630,0:03:32.280
What's going on over here?

0:03:32.280,0:03:34.080
Well, humanity has known[br]about these elements

0:03:34.080,0:03:35.550
for a long time now,

0:03:35.550,0:03:38.070
and some of these symbols[br]are taken from the old names

0:03:38.070,0:03:40.740
from different languages[br]like Greek, Latin,

0:03:40.740,0:03:42.600
Arabic, German, and so on.

0:03:42.600,0:03:45.210
For example, Na stands for natrium,

0:03:45.210,0:03:47.306
Latin word for sodium.

0:03:47.306,0:03:49.650
Au comes from aurum.

0:03:49.650,0:03:54.000
Pb comes from plumbum,[br]the Latin word for lead.

0:03:54.000,0:03:55.650
Fun fact earlier pipes

0:03:55.650,0:03:57.660
in the Roman Empire were made from lead,

0:03:57.660,0:03:59.160
and therefore people who used

0:03:59.160,0:04:01.020
to fix those pipes are called plumbers,

0:04:01.020,0:04:02.490
and the name is stuck today.

0:04:02.490,0:04:05.700
And W comes from the German, wolfram.

0:04:05.700,0:04:07.357
Now again, you might be thinking,

0:04:07.357,0:04:09.540
"Oh my God, how am I supposed[br]to remember all of this?"

0:04:09.540,0:04:11.100
Don't worry, we don't have to do that.

0:04:11.100,0:04:13.350
As we start talking about[br]some of the common elements

0:04:13.350,0:04:14.220
over and over again,

0:04:14.220,0:04:15.810
we'll start familiarizing[br]ourselves with them.

0:04:15.810,0:04:17.640
So don't worry about it.

0:04:17.640,0:04:20.010
So in summary, all the[br]matter that you see,

0:04:20.010,0:04:21.690
almost everything in the universe,

0:04:21.690,0:04:24.240
is made of a few, about[br]a hundred elements,

0:04:24.240,0:04:26.130
which we also call the pure substances.

0:04:26.130,0:04:27.480
They're arranged this way

0:04:27.480,0:04:29.790
in what we call the periodic table.

0:04:29.790,0:04:31.530
And just like how learning[br]the English language

0:04:31.530,0:04:32.550
is basically figuring out

0:04:32.550,0:04:34.230
how we can combine these different letters

0:04:34.230,0:04:36.750
to form very interesting[br]words and sentences.

0:04:36.750,0:04:38.700
The trick to learning about matter

0:04:38.700,0:04:41.190
is learning how we can combine[br]these different elements

0:04:41.190,0:04:43.950
to form interesting new things.

0:04:43.950,0:04:45.660
It's kind of like legos,

0:04:45.660,0:04:48.030
the plastic building blocks[br]we used to play with before.

0:04:48.030,0:04:49.350
Well, imagine we had a hundred different

0:04:49.350,0:04:50.670
kinds of legos with us.

0:04:50.670,0:04:52.770
Then by combining them in[br]different combinations,

0:04:52.770,0:04:55.470
you can build up almost anything you want.

0:04:55.470,0:04:56.670
And now you can imagine some

0:04:56.670,0:04:58.440
of these lego structures[br]are like mountains

0:04:58.440,0:05:00.270
and others are like cats.

0:05:00.270,0:05:01.890
And we can build whatever we want.

0:05:01.890,0:05:03.750
We can let our imagination lose over here,

0:05:03.750,0:05:05.040
which is pretty awesome.

0:05:05.040,0:05:07.950
But if you break them all[br]down into their basic pieces,

0:05:07.950,0:05:10.983
you get back your elements.