Ionization energy trends

WEBVTT
Kind: captions
Language: en

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- [Voiceover] So, let's
talk a little bit about

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a word you might have
heard and that is Ion.

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Let's talk about what it is
and then we'll talk about

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trends in the periodic table on,

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on I guess how hard it is
to make something an Ion.

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In particular how hard it is

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to make something a positive ion.

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So, an ion is just an atom or a molecule

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that has charge and
it'll have charge if the

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protons are not equal to the electrons.

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Neutrons are obviously
also constituent of atoms

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but neutrons are neutral.

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What you're gonna get your charge

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from are your protons or electrons.

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So, you're going to have a net charge.

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If your number of, number of protons,

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and this is for an atom or molecule.

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A molecule's just a bunch of,

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a bunch of atoms bonded together.

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If the number of protons does not equal

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the number of electrons.

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And you can have positive
ions if the protons are

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more than the number
of electrons, protons,

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or positive electrons or negative.

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And you can have negative
ions if the number

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of electrons are greater
than the number of protons.

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For example, for example, if you just had

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Hydrogen in it's neutral state

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has one proton and one electron,

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but if you were to take
one of those electrons away

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then Hydrogen would have a positive charge

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and essentially it would just be,

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in its most common isotope it would just

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be a proton by itself.

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And so, when we talk about
a positive ion like this

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where our protons are
more than our electrons,

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the number of protons are more
than the number of electrons,

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we call these cations, cations.

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Cation, once again, just
another word positive ion.

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Likewise, we can have negative ions.

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So, say for example, Fluorine.

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So, Fluorine gains an electron,

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it's going to have a negative charge.

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It's gonna have a negative
charge of negative one,

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and a negative ion we call an anion.

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And the way that I remember this is

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a kind of means the opposite
or the negation of something.

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So, this is a negative ion.

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We've negating, you can somehow

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think we are negating the ion.

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So, with that out of the way,

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let's think about how
hard it will be ionize

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different elements in the periodic table.

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In particular, how hard it
is to turn them into cations.

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And to think about that, we'll introduce

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an idea called ionization energy.

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Ionization...

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Ionization energy...

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Energy...

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And this is defined, this is defined as

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the energy required, energy required

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to remove an electron,
to remove an electron.

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So, it could've even been
called cationization energy

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because you really see
energy required to remove

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an electron and make the
overall atom more positive.

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So, let's think about the trends.

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And we already have a
little bit of background

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on the different groups
of the periodic table.

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So, for example, if we were to focus on,

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especially we could look at group one,

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and we've already talked
about how Hydrogen's

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a bit of a special case in group one

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but if we look at
everything below Hydrogen.

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If we look at the Alkali, if we look

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at the Alkali metals here

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we've already talked about the fact

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that these are very willing
to lose an electron.

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Why? Because if they lose an electron

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they get to the electron configuration

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of the noble gas before it.

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So, if Lithium loses an electron

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then it has an outer shell
electron configuration of Helium.

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It has two outer electrons
and that's kind of,

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we typically talk about the Octet Rule

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but if we're talking about
characters like Lithium or Helium

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they're happy with two 'cause you can

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only put two electrons
in that first shell.

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But all the rest of 'em,
Sodium, Potassium, etc., etc.,

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if you take an electron away from them

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then their outermost shell,

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well, all of them in their outermost shell

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they're going to have the
electron configuration

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of the noble gas before it

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and for Sodium on down that outer shell

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is going to have that perfect eight.

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Lithium, if you remove an electron,

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it would get to Helium and it would have

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two electrons in its outer shell.

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So, you can imagine that
the ionization energy

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right over here, the energy
required to remove electrons

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from your Alkali Metals is very low.

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So, let me just write down this is...

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So, when I say low, I'm talking
about low ionization energy.

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Low.

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Now, what happens as we move to the right

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of the periodic table?

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In fact, let's go all the way

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to the right on the periodic table.

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Well, if we go here to the Noble Gases,

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the Noble Gases we've
already talked about.

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They're very, very, very stable.

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They don't want no one,

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they don't want their electron
configurations messed with.

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So, it would be very hard...

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Neon on down has their eight electrons

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that (mumbling) Octet Rule.

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Helium has two which is
full for the first shell,

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and so it's very hard to
remove an electron from here,

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and so it has a very
high ionization energy.

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Low energy, easy to remove electrons.

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Or especially the first electron,

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and then here you have a
high ionization energy.

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I know you have trouble seeing that H.

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So, this is high, high ionization energy,

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and that's the general trend
across the periodic table.

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As you go from left to right,

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you go from low ionization
energy to high ionization energy.

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Now, what about trends up
and down the periodic table?

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Well, within any group, if we,

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even if we look at the Alkali,

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if we look at the Alkali
Metals right over here,

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if we're down at the bottom,

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if we're looking at, if we're looking at,

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say, Cesium right over here,

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that electron in the, one,
two, three, four, five, six,

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in the sixth shell, that's going to be

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further from that one electron

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that Lithium has and its second shell.

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So, it's going to be, it's
going to be further away.

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It's not going to be as
closely bound to the nucleus,

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I guess you could say.

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So, this is going to be even,

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that one electron's gonna
even easier to remove

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than the one electron in the
outermost shell of Lithium.

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So, this one has even lower, even lower,

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even lower...

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And that's even going to be
true of the Noble Gases out here

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that Xenon, that it's electrons
in its outermost shell,

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even though it has
eight valence electrons,

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they're further away from the nucleus,

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and so they're a little,
the energy required

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to remove them is still going to be high

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but it's going to be lower
than the energy from,

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from say Neon or Helium.

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So, this is low.

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So, once again, ionization
energy low to high

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as we go from left to right,

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and low to high as we
go from bottom to top.

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Or we could say a general trend

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that if we go from the
bottom left to the top right

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we go from low ionization energy,

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very easy to remove an electron

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from these characters right over here

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to high ionization energy,

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very hard to move, remove an electron

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from these characters over here.

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And you can see it if, you could see

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in a trend of actual
measured ionization energies

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and I like to see charts like this because

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it kind of show you where
the periodic table came from

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when people noticed these
kind of periodic trends.

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It's like, hey, it looks like

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there's some common patterns here.

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But on this one in particular
we see on this axis

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we have ionization energy
and electron volts,

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that's actually, it's literally a,

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this is units of energy.

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You could convert it
to Joules if you like.

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Then over here, we're
increasing the atomic numbers.

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So, we're (mumbling), we're starting with

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Hydrogen then we go to Helium,

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and we keep, and then we go,

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go from Hydrogen to Helium to Lithium

00:08:00.065 --> 00:08:02.247
and let me show you what's
happening right over here.

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So, you go to Hydrogen to Helium.

00:08:05.284 --> 00:08:07.464
So, Helium here is very stable,

00:08:07.464 --> 00:08:10.548
so it's very hard to remove an electron.

00:08:10.548 --> 00:08:12.246
And then you go to Lithium.

00:08:12.246 --> 00:08:14.847
Lithium, as we said,
this is an Alkali metal.

00:08:14.847 --> 00:08:17.305
You remove an electron,
it gets to a stable state.

00:08:17.305 --> 00:08:20.166
So, it takes very low energy
to remove that electron.

00:08:20.166 --> 00:08:22.626
And then as we go from left to
right on the periodic table,

00:08:22.626 --> 00:08:26.467
as we go from Alkali Metal to Noble Gases

00:08:26.482 --> 00:08:29.225
we see that the ionization
energy increases.

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And there are these little dips here

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which you could think about why these...

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(mumbling) Or theorize why
these dips are occurring,

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what you see in this general trend

00:08:36.726 --> 00:08:40.904
as we go from Alkali
Metals to Noble Gases.

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Alkali Metals to Noble Gases.

00:08:43.486 --> 00:08:45.948
Alkali Metals to Noble Gases.

00:08:45.948 --> 00:08:47.025
Now, one thing you might be saying is,

00:08:47.025 --> 00:08:50.149
"Hey, look, you had from here to here,

00:08:50.149 --> 00:08:52.028
"that's the same distance as here to here,

00:08:52.028 --> 00:08:53.578
"but now we have a larger distance here.

00:08:53.578 --> 00:08:54.819
"What's going on here?"

00:08:54.819 --> 00:08:55.729
Well, we have to remember now we

00:08:55.729 --> 00:08:58.577
have all of our D block elements.

00:08:58.577 --> 00:09:02.848
So, now, once we get, once we get to the,

00:09:02.848 --> 00:09:05.908
once we get over here we're now adding

00:09:05.908 --> 00:09:08.268
all of the D block elements.

00:09:08.268 --> 00:09:09.888
(mumbling) On the fourth period

00:09:09.888 --> 00:09:13.369
and so we have those, we
have those added here,

00:09:13.369 --> 00:09:15.330
so you have D block
elements, D block elements,

00:09:15.330 --> 00:09:18.708
and then here you have you
F and D block elements.

00:09:18.708 --> 00:09:20.776
And so, you see the general trend

00:09:20.776 --> 00:09:24.780
that your Alkali, your Alkali Metals

00:09:24.780 --> 00:09:26.829
are very low ionization energy.

00:09:26.829 --> 00:09:31.742
Your Noble Gases, very
high ionization energy.

00:09:31.742 --> 00:09:35.059
But as they get, as the
atoms get larger and larger

00:09:35.059 --> 00:09:37.537
the ionization energy
goes lower and lower,

00:09:37.537 --> 00:09:39.239
and sends something like Radon,

00:09:39.239 --> 00:09:40.816
which even though it's Noble Gas

00:09:40.816 --> 00:09:43.897
it's ionization energy because
those outermost electrons

00:09:43.897 --> 00:09:46.551
are further away from the nucleus

00:09:46.551 --> 00:09:48.652
or they're quite far
away from the nucleus,

00:09:48.652 --> 00:09:52.699
that its ionization energy is actually,

00:09:52.699 --> 00:09:54.349
its ionization energy is

00:09:54.349 --> 00:09:58.258
actually less then that of Hydrogen.

00:09:58.258 --> 00:10:01.306
Anyway, hope you found that interesting.


Using Khan Academy

WEBVTT
Kind: captions
Language: en

00:00:00.272 --> 00:00:01.999
- [Voiceover] Welcome to the Khan Academy.

00:00:01.999 --> 00:00:03.646
The goal of this video is to show you

00:00:03.646 --> 00:00:06.492
all the different things
that Khan Academy has.

00:00:06.492 --> 00:00:08.299
It has videos, it has exercises,

00:00:08.299 --> 00:00:11.621
it has an adaptive,
super, I guess you could

00:00:11.621 --> 00:00:14.841
call it robot tutor
thing that will guide you

00:00:14.841 --> 00:00:17.066
through content and
make sure you master it.

00:00:17.066 --> 00:00:19.684
So let's just take each
of those one by one.

00:00:19.684 --> 00:00:21.634
Many of y'all are probably
coming to this saying,

00:00:21.634 --> 00:00:24.522
"Hey, I have an exam tomorrow on DNA," or

00:00:24.522 --> 00:00:26.746
"I didn't understand quite
what's happening in class."

00:00:26.746 --> 00:00:29.151
There the best thing to do might just be

00:00:29.151 --> 00:00:31.617
go to the search bar,
let me make sure you can

00:00:31.617 --> 00:00:34.769
see the search bar, to
go to the search bar

00:00:34.769 --> 00:00:37.650
and you could search for DNA.

00:00:37.774 --> 00:00:39.862
When you do that you see your first choice

00:00:39.862 --> 00:00:41.545
right over is a DNA video.

00:00:41.545 --> 00:00:44.180
This is actually the main video on DNA

00:00:44.180 --> 00:00:45.776
and which you could start watching.

00:00:45.776 --> 00:00:48.124
Or if you look to the
right right over here,

00:00:48.124 --> 00:00:50.876
you see that there's
all other related videos

00:00:50.876 --> 00:00:53.594
under heredity and genetics.

00:00:53.594 --> 00:00:55.125
Then you can start browsing from there.

00:00:55.125 --> 00:00:56.845
You could say, "Okay,
let me back up a second.

00:00:56.845 --> 00:00:59.291
"Let me go back to just all of biology."

00:00:59.291 --> 00:01:00.976
I can see all of the sections are there.

00:01:00.976 --> 00:01:02.489
Similarly, you might wanna search

00:01:02.489 --> 00:01:04.185
for something in mathematics.

00:01:04.416 --> 00:01:06.675
You might wanna say,
"Oh, I have a question

00:01:06.675 --> 00:01:07.999
"about quadratics."

00:01:08.660 --> 00:01:09.722
Quadratics.

00:01:09.722 --> 00:01:11.128
I'm gonna do a search there.

00:01:11.128 --> 00:01:12.773
Okay, well let's see, there's something

00:01:12.773 --> 00:01:15.567
about using the quadratic formula,

00:01:15.567 --> 00:01:16.652
factoring quadratics 2.

00:01:16.652 --> 00:01:19.039
I don't know which of
these is right for me,

00:01:19.039 --> 00:01:22.855
so let me just go into one of these

00:01:22.855 --> 00:01:24.844
and start getting a little bit of context.

00:01:25.413 --> 00:01:28.315
You see that what I
actually just clicked on

00:01:28.315 --> 00:01:30.268
is actually an exercise that gets me

00:01:30.268 --> 00:01:32.554
to solve quadratics by factoring two.

00:01:33.030 --> 00:01:35.095
I need to write my answer here.

00:01:35.095 --> 00:01:37.401
If I don't know the answer,
I have a bunch of hints.

00:01:37.401 --> 00:01:39.436
If this all looks like Greek to me,

00:01:39.436 --> 00:01:42.397
I can click on a video

00:01:42.397 --> 00:01:45.137
that solves a very similar problem.

00:01:45.432 --> 00:01:47.859
Or I might hey, this isn't
what I was looking for.

00:01:47.859 --> 00:01:49.995
But look over here, they're solving

00:01:49.995 --> 00:01:51.553
a quadratic equation by factoring.

00:01:51.553 --> 00:01:53.132
Factoring quadratic equations.

00:01:53.132 --> 00:01:54.625
Maybe this is what I need to learn.

00:01:54.625 --> 00:01:56.785
Or maybe I'm not even
thinking about this stuff,

00:01:56.785 --> 00:01:59.051
so let me just move up a level

00:01:59.087 --> 00:02:01.109
to quadratic equations.

00:02:01.324 --> 00:02:03.430
Now I can see the whole topic here.

00:02:03.430 --> 00:02:05.636
Solving quadratics by taking square root.

00:02:05.636 --> 00:02:07.644
Solving quadratics by factoring.

00:02:07.644 --> 00:02:10.233
Completing the square,
the quadratic formula.

00:02:10.233 --> 00:02:12.782
Quadratic equation, graphing quadratics.

00:02:12.916 --> 00:02:14.906
In general if you just wanna browse,

00:02:14.906 --> 00:02:16.311
you say "Let me just see all the subjects

00:02:16.311 --> 00:02:17.669
"that are available on Khan Academy."

00:02:17.669 --> 00:02:19.360
You can go this drop-down right over here.

00:02:19.360 --> 00:02:21.079
This starts to give you
a sense of the breadth

00:02:21.079 --> 00:02:22.874
of the content on Khan Academy.

00:02:22.874 --> 00:02:26.436
Just in math, each of
these is an entire subject.

00:02:26.821 --> 00:02:31.148
K-2nd math, you have pre-calculus,

00:02:31.148 --> 00:02:33.170
goes all the way up to
multivariable calculus,

00:02:33.170 --> 00:02:34.324
intergal calculus.

00:02:34.324 --> 00:02:36.960
If I were to click on
any one of these things,

00:02:39.375 --> 00:02:42.682
it's going to take me into
something called a mission.

00:02:42.682 --> 00:02:46.109
A mission is going to give
me a set of exercises.

00:02:46.109 --> 00:02:49.504
We call this right over
here the mission warm-up.

00:02:49.702 --> 00:02:52.635
Based on how I perform on
these calculus questions,

00:02:52.635 --> 00:02:54.653
the system is starting to get a sense

00:02:54.653 --> 00:02:57.485
of what I know and don't
know and it will use that

00:02:57.485 --> 00:03:00.194
to give me guided practice
so I can learn more

00:03:00.194 --> 00:03:01.690
and more and more calculus.

00:03:01.690 --> 00:03:03.381
Eventually mastering calculus.

00:03:03.381 --> 00:03:04.909
At any point if I have difficulty,

00:03:04.909 --> 00:03:06.766
there's always videos
here that will help me

00:03:06.766 --> 00:03:09.075
understand the actual calculus.

00:03:09.447 --> 00:03:12.406
Once I'm done with that, I
will go to this dashboard

00:03:12.406 --> 00:03:14.451
and it'll just tell me
about how much have I

00:03:14.451 --> 00:03:17.187
progressed in integral
calculus, what have I mastered,

00:03:17.187 --> 00:03:18.736
what have I not practiced yet,

00:03:18.736 --> 00:03:20.620
what are my different badges.

00:03:20.620 --> 00:03:22.348
If you do not wanna move immediately

00:03:22.348 --> 00:03:24.104
into this mission world and you wanna say

00:03:24.104 --> 00:03:26.272
what does Khan Academy have when it comes

00:03:26.272 --> 00:03:28.466
to calculus in an unguided way,

00:03:28.466 --> 00:03:30.420
that's where you go view full list

00:03:30.420 --> 00:03:32.268
of integral calculus content.

00:03:32.391 --> 00:03:34.211
Then you will go to this page,

00:03:34.211 --> 00:03:35.919
where you see the breadth and scope

00:03:35.919 --> 00:03:37.468
of the integral content.

00:03:37.468 --> 00:03:38.774
Integrals, integration techniques,

00:03:38.774 --> 00:03:41.332
integration applications,
sequences and series,

00:03:41.332 --> 00:03:43.588
AP calculus practice problems.

00:03:43.588 --> 00:03:45.762
If you click there, you see the different

00:03:46.593 --> 00:03:48.373
tutorials within, indefinite integrals

00:03:48.373 --> 00:03:51.340
as anti-derivative, area
under a rate function

00:03:51.340 --> 00:03:52.412
as net change.

00:03:52.412 --> 00:03:53.750
Hopefully that gives you sense of things.

00:03:53.750 --> 00:03:55.372
We don't just have math and we don't just

00:03:55.372 --> 00:03:57.766
have science, we have whole section here

00:03:57.766 --> 00:04:00.690
on computer programming,
which is tons of fun

00:04:00.690 --> 00:04:04.895
where you can write your
own computer program.

00:04:05.895 --> 00:04:07.766
I'm using my son's account right now.

00:04:08.151 --> 00:04:10.971
This is a computer program that we wrote.

00:04:11.363 --> 00:04:12.757
This right here is a computer program

00:04:12.757 --> 00:04:14.894
that we wrote together the other day.

00:04:15.402 --> 00:04:18.227
It was good father/son bonding time.

00:04:18.254 --> 00:04:20.810
And we have things in
the arts and humanities,

00:04:20.810 --> 00:04:23.034
like history and art history,

00:04:23.034 --> 00:04:25.655
which is also very, very, very exciting.

00:04:25.655 --> 00:04:27.580
And we have partner content.

00:04:27.580 --> 00:04:30.601
We have partner content from the likes of

00:04:32.312 --> 00:04:34.419
The Museum of Modern Art, Explortorium,

00:04:34.419 --> 00:04:36.778
JP Getty Museum, The British Museums.

00:04:36.778 --> 00:04:37.920
So a lot of stuff here.

00:04:37.920 --> 00:04:40.008
Hopefully this video gives you a flavor

00:04:40.107 --> 00:04:43.199
of the different ways
you can use Khan Academy.


Coulomb's Law

WEBVTT
Kind: captions
Language: en

00:00:00.086 --> 00:00:01.486
- [Voiceover] So we've already started to

00:00:01.486 --> 00:00:03.367
familiarize ourselves
with the notion of charge.

00:00:03.367 --> 00:00:06.455
We've seen that if two
things have the same charge,

00:00:06.455 --> 00:00:08.312
so they're either both positive,

00:00:08.312 --> 00:00:10.773
or they are both negative,

00:00:10.773 --> 00:00:13.142
then they are going to repel each other.

00:00:13.142 --> 00:00:15.022
So in either of these cases

00:00:15.022 --> 00:00:17.321
these things are going
to repel each other.

00:00:17.321 --> 00:00:18.622
But if they have different charges,

00:00:18.622 --> 00:00:19.945
they are going to attract each other.

00:00:19.945 --> 00:00:23.535
So if I have a positive
and I have a negative

00:00:23.535 --> 00:00:25.007
they are going to attract each other.

00:00:25.007 --> 00:00:27.613
This charge is a property of matter

00:00:27.613 --> 00:00:28.722
that we've started to observe.

00:00:28.722 --> 00:00:31.089
We've started to observe of
how these different charges,

00:00:31.089 --> 00:00:32.329
this framework that we've created,

00:00:32.329 --> 00:00:34.659
how these things start to
interact with each other.

00:00:34.659 --> 00:00:36.337
So these things are going to,

00:00:36.337 --> 00:00:39.194
these two things are going
to attract each other.

00:00:39.194 --> 00:00:42.471
But the question is, what causes,

00:00:42.471 --> 00:00:44.650
how can we predict how strong the force

00:00:44.650 --> 00:00:47.320
of attraction or repulsion is going to be

00:00:47.320 --> 00:00:49.363
between charged particles?

00:00:49.363 --> 00:00:51.918
And this was a question
people have noticed,

00:00:51.918 --> 00:00:53.844
I guess what you could
call electrostatics,

00:00:53.844 --> 00:00:57.583
for a large swathe of
recorded human history.

00:00:57.583 --> 00:00:59.673
But it wasn't until the 16 hundreds

00:00:59.673 --> 00:01:01.109
and especially the 17 hundreds,

00:01:01.109 --> 00:01:02.761
that people started to seriously view this

00:01:02.761 --> 00:01:05.261
as something that they could manipulate

00:01:05.261 --> 00:01:07.892
and even start to predict
in a kind of serious,

00:01:07.892 --> 00:01:10.098
mathematical, scientific way.

00:01:10.098 --> 00:01:12.725
And it wasn't until
1785, and there were many

00:01:12.725 --> 00:01:13.584
that came before Coulomb,

00:01:13.584 --> 00:01:17.235
but in 1785 Coulomb formally published

00:01:17.235 --> 00:01:20.010
what is known as Coulomb's law.

00:01:20.010 --> 00:01:22.536
And the purpose of Coulomb's law,

00:01:22.536 --> 00:01:24.355
Coulomb's law,

00:01:24.355 --> 00:01:28.047
is to predict what is
going to be the force of

00:01:28.047 --> 00:01:31.321
the electrostatic force
of attraction or repulsion

00:01:31.321 --> 00:01:33.271
between two forces.

00:01:33.271 --> 00:01:35.407
And so in Coulomb's law, what it states is

00:01:35.407 --> 00:01:36.917
is if I have two charges,

00:01:36.917 --> 00:01:39.440
so let me, let's say this
charge right over here,

00:01:39.440 --> 00:01:40.407
and I'm gonna make it in white,

00:01:40.407 --> 00:01:41.862
because it could be positive or negative,

00:01:41.862 --> 00:01:45.113
but I'll just make it q
one, it has some charge.

00:01:45.113 --> 00:01:47.783
And then I have in Coulombs.

00:01:47.783 --> 00:01:50.709
and then another charge
q two right over here.

00:01:50.709 --> 00:01:52.195
Another charge, q two.

00:01:52.195 --> 00:01:55.468
And then I have the distance
between them being r.

00:01:55.468 --> 00:01:58.872
So the distance between these two charges

00:01:58.872 --> 00:02:01.313
is going to be r.

00:02:01.313 --> 00:02:05.314
Coulomb's law states that the force,

00:02:05.314 --> 00:02:06.870
that the magnitude of the force,

00:02:06.870 --> 00:02:09.005
so it could be a repulsive force

00:02:09.005 --> 00:02:10.515
or it could be an attractive force,

00:02:10.515 --> 00:02:12.512
which would tell us the
direction of the force

00:02:12.512 --> 00:02:14.114
between the two charges,

00:02:14.114 --> 00:02:15.739
but the magnitude of the force,

00:02:15.739 --> 00:02:18.456
which I'll just write it as F,

00:02:18.456 --> 00:02:20.423
the magnitude of the electrostatic force,

00:02:20.423 --> 00:02:21.822
I'll write this sub e here,

00:02:21.822 --> 00:02:23.624
this subscript e for electrostatic.

00:02:23.624 --> 00:02:25.630
Coulomb stated, well this is going to be,

00:02:25.630 --> 00:02:27.697
and he tested this, he didn't
just kind of guess this.

00:02:27.697 --> 00:02:30.739
People actually were assuming
that it had something

00:02:30.739 --> 00:02:34.732
to do with the products of the magnitude

00:02:34.732 --> 00:02:37.305
of the charges and that as the particles

00:02:37.305 --> 00:02:38.680
got further and further away

00:02:38.680 --> 00:02:40.653
the electrostatic force dissipated.

00:02:40.653 --> 00:02:42.418
But he was able to actually measure this

00:02:42.418 --> 00:02:44.856
and feel really good
about stating this law.

00:02:44.856 --> 00:02:47.317
Saying that the magnitude
of the electrostatic force

00:02:47.317 --> 00:02:49.012
is proportional,

00:02:49.012 --> 00:02:50.800
is proportional,

00:02:50.800 --> 00:02:53.958
to the product of the
magnitudes of the charges.

00:02:53.958 --> 00:02:58.532
So I could write this
as q one times q two,

00:02:58.532 --> 00:03:00.343
and I could take the
absolute value of each,

00:03:00.343 --> 00:03:01.693
which is the same thing as just

00:03:01.708 --> 00:03:03.563
taking the absolute value of the product.

00:03:03.563 --> 00:03:05.335
Here's why I'm taking the
absolute value of the product,

00:03:05.335 --> 00:03:06.914
well, if they're different charges,

00:03:06.914 --> 00:03:08.121
this will be a negative number,

00:03:08.121 --> 00:03:10.907
but we just want the overall
magnitude of the force.

00:03:10.907 --> 00:03:12.417
So we could take, it's proportional to

00:03:12.417 --> 00:03:15.063
the absolute value of the
product of the charges

00:03:15.063 --> 00:03:17.214
and it's inversely proportional to

00:03:17.214 --> 00:03:18.965
not just the distance between them,

00:03:18.965 --> 00:03:23.167
not just to r, but to the
square of the distance.

00:03:23.167 --> 00:03:25.884
The square of the distance between them.

00:03:25.884 --> 00:03:27.323
And what's pretty neat about this

00:03:27.323 --> 00:03:31.550
is how close it mirrors
Newton's law of gravitation.

00:03:31.550 --> 00:03:34.856
Newton's law of gravitation,
we know that the force,

00:03:34.856 --> 00:03:37.447
due to gravity between two masses,

00:03:37.447 --> 00:03:40.117
remember mass is just
another property of matter,

00:03:40.117 --> 00:03:42.554
that we sometimes feel is
a little bit more tangible

00:03:42.554 --> 00:03:45.342
because it feels like we can
kind of see weight and volume,

00:03:45.342 --> 00:03:46.897
but that's not quite the same,

00:03:46.897 --> 00:03:50.766
or we feel like we can feel or

00:03:50.766 --> 00:03:52.818
internalize things like weight and volume

00:03:52.818 --> 00:03:54.281
which are related to mass,

00:03:54.281 --> 00:03:56.394
but in some ways it is
just another property,

00:03:56.394 --> 00:03:58.043
another property, especially
as you get into more

00:03:58.043 --> 00:04:00.463
of a kind of fancy physics.

00:04:00.463 --> 00:04:04.483
Our everyday notion of even mass starts to

00:04:04.483 --> 00:04:06.053
become a lot more interesting.

00:04:06.053 --> 00:04:07.937
But Newton's law of gravitation says,

00:04:07.937 --> 00:04:09.595
look the magnitude of the force of gravity

00:04:09.595 --> 00:04:12.322
between two masses is going
to be proportional to,

00:04:12.322 --> 00:04:14.459
by Newton's, by the gravitational concept,

00:04:14.459 --> 00:04:17.686
proportional to the
product of the two masses.

00:04:17.686 --> 00:04:19.242
Actually, let me do it
in those same colors

00:04:19.242 --> 00:04:21.957
so you can see the relationship.

00:04:21.957 --> 00:04:25.033
It's going to be proportional to

00:04:25.033 --> 00:04:28.971
the product of the two
masses, m one m two.

00:04:28.971 --> 00:04:30.782
And it's going to be
inversely proportional

00:04:30.782 --> 00:04:32.895
to the square of the distance.

00:04:32.895 --> 00:04:35.820
The square of the distance
between two masses.

00:04:35.820 --> 00:04:37.562
Now these proportional
personality constants

00:04:37.562 --> 00:04:39.442
are very different. Gravitational force,

00:04:39.442 --> 00:04:42.628
we kind of perceive this
is as acting, being strong,

00:04:42.628 --> 00:04:45.236
it's a weaker force in close range.

00:04:45.236 --> 00:04:47.186
But we kind of imagine it
as kind of what dictates

00:04:47.186 --> 00:04:49.386
what happens in the,

00:04:49.386 --> 00:04:52.086
amongst the stars and
the planets and moons.

00:04:52.086 --> 00:04:54.199
While the electrostatic
force at close range

00:04:54.199 --> 00:04:55.500
is a much stronger force.

00:04:55.500 --> 00:04:58.495
It can overcome the
gravitational force very easily.

00:04:58.495 --> 00:05:00.143
But it's what we consider happening

00:05:00.143 --> 00:05:03.347
at either an atomic level
or kind of at a scale

00:05:03.347 --> 00:05:06.482
that we are more familiar to operating at.

00:05:06.482 --> 00:05:08.433
But needless to say,
it is very interesting

00:05:08.433 --> 00:05:12.078
to see how this parallel
between these two things,

00:05:12.078 --> 00:05:14.795
it's kind of these
patterns in the universe.

00:05:14.795 --> 00:05:16.884
But with that said, let's actually apply

00:05:16.884 --> 00:05:18.510
let's actually apply Coulomb's law,

00:05:18.510 --> 00:05:21.761
just to make sure we feel
comfortable with the mathematics.

00:05:21.761 --> 00:05:24.454
So let's say that I have a charge here.

00:05:24.454 --> 00:05:26.752
Let's say that I have a charge here,

00:05:26.752 --> 00:05:29.353
and it has a positive
charge of, I don't know,

00:05:29.353 --> 00:05:32.092
let's say it is positive five

00:05:32.092 --> 00:05:36.606
times 10 to the negative three Coulombs.

00:05:36.606 --> 00:05:40.173
So that's this one right over here.

00:05:40.173 --> 00:05:41.449
That's its charge.

00:05:41.449 --> 00:05:45.490
And let's say I have this
other charge right over here

00:05:45.490 --> 00:05:47.766
and this has a negative charge.

00:05:47.766 --> 00:05:49.206
And it is going to be,

00:05:49.206 --> 00:05:53.408
it is going to be, let's
say it's negative one...

00:05:53.408 --> 00:05:57.404
Negative one times 10

00:05:57.404 --> 00:06:01.048
to the negative one Coulombs.

00:06:01.048 --> 00:06:03.230
And let's say that the
distance between the two,

00:06:03.230 --> 00:06:05.565
let's that this distance right here

00:06:05.565 --> 00:06:10.393
is 0.5 meters.

00:06:10.393 --> 00:06:14.254
So given that, let's figure out what the

00:06:14.254 --> 00:06:15.717
what the electrostatic force

00:06:15.717 --> 00:06:17.126
between these two are going to be.

00:06:17.126 --> 00:06:17.946
And we can already predict that

00:06:17.946 --> 00:06:19.363
it's going to be an
attractive force because

00:06:19.363 --> 00:06:20.778
they have different signs.

00:06:20.778 --> 00:06:22.010
And that was actually
part of Coulomb's law.

00:06:22.010 --> 00:06:23.287
This is the magnitude of the force,

00:06:23.287 --> 00:06:25.386
if these have different
signs, it's attractive,

00:06:25.386 --> 00:06:27.280
if they have the same sign then they

00:06:27.280 --> 00:06:28.905
are going to repel each other.

00:06:28.905 --> 00:06:29.672
And I know what you're saying,

00:06:29.672 --> 00:06:30.665
"Well in order to actually calculate it,

00:06:30.665 --> 00:06:32.481
"I need to know what K is."

00:06:32.481 --> 00:06:35.628
What is this electrostatic constant?

00:06:35.628 --> 00:06:39.099
What is this electrostatic
constant going to actually be?

00:06:39.099 --> 00:06:42.025
And so you can measure that
with a lot of precision,

00:06:42.025 --> 00:06:44.137
and we have kind of modern numbers on it,

00:06:44.137 --> 00:06:45.322
but the electrostatic constant,

00:06:45.322 --> 00:06:47.086
especially for the sake of this problem,

00:06:47.086 --> 00:06:52.086
I mean if we were to get
really precise it's 8.987551,

00:06:52.102 --> 00:06:55.445
we could keep gone on and
on times 10 to the ninth.

00:06:55.445 --> 00:06:59.578
But for the sake of our
little example here,

00:06:59.578 --> 00:07:00.902
where we really only have

00:07:00.902 --> 00:07:02.457
one significant digit for each of these.

00:07:02.457 --> 00:07:04.105
Let's just get an approximation,

00:07:04.105 --> 00:07:05.406
it'll make the math a little bit easier,

00:07:05.406 --> 00:07:07.263
I won't have to get a calculator out,

00:07:07.263 --> 00:07:08.401
let's just say it's approximately

00:07:08.401 --> 00:07:11.157
nine times 10 to the ninth.

00:07:11.157 --> 00:07:14.346
Nine times 10 to the ninth.

00:07:14.346 --> 00:07:18.223
Nine times, actually let me
make sure it says approximately,

00:07:18.223 --> 00:07:19.638
because I am approximating here,

00:07:19.638 --> 00:07:21.869
nine times 10 to the ninth.

00:07:21.869 --> 00:07:23.726
And what are the units going to be?

00:07:23.726 --> 00:07:25.282
Well in the numerator here,

00:07:25.282 --> 00:07:26.884
where I multiply Coulombs times Coulombs,

00:07:26.884 --> 00:07:29.020
I'm going to get Coulombs squared.

00:07:29.020 --> 00:07:30.831
This right over here is going to give me,

00:07:30.831 --> 00:07:33.873
that's gonna give me Coulombs squared.

00:07:33.873 --> 00:07:35.312
And this down over here is going

00:07:35.312 --> 00:07:37.565
to give me meters squared.

00:07:37.565 --> 00:07:39.491
This is going to give me meters squared.

00:07:39.491 --> 00:07:41.117
And what I want is to get rid of

00:07:41.117 --> 00:07:42.486
the Coulombs and the meters and end up

00:07:42.486 --> 00:07:43.904
with just the Newtons.

00:07:43.904 --> 00:07:47.065
And so the units here are actually,

00:07:47.065 --> 00:07:49.732
the units here are Newtons.

00:07:49.732 --> 00:07:52.332
Newton and then meters squared,

00:07:52.332 --> 00:07:53.563
and that cancels out
with the meters squared

00:07:53.563 --> 00:07:55.095
in the denominator.

00:07:55.095 --> 00:07:59.617
Newton meter squared over Coulomb squared.

00:07:59.617 --> 00:08:02.592
Over, over Coulomb squared.

00:08:02.592 --> 00:08:04.307
Let me do that in white.

00:08:04.307 --> 00:08:08.241
Over, over Coulomb squared.

00:08:08.241 --> 00:08:10.135
So, these meter squared will cancel those.

00:08:10.135 --> 00:08:11.625
Those Coulomb squared in the denomin...

00:08:11.625 --> 00:08:13.061
over here will cancel with those,

00:08:13.061 --> 00:08:14.500
and you'll be just left with Newtons.

00:08:14.500 --> 00:08:15.244
But let's actually do that.

00:08:15.244 --> 00:08:16.706
Let's apply it to this example.

00:08:16.706 --> 00:08:17.867
I encourage you to pause the video

00:08:17.867 --> 00:08:20.654
and apply this information
to Coulomb's law

00:08:20.654 --> 00:08:22.279
and figure out what
the electrostatic force

00:08:22.279 --> 00:08:25.089
between these two
particles is going to be.

00:08:25.089 --> 00:08:27.387
So I'm assuming you've had your go at it.

00:08:27.387 --> 00:08:29.244
So it is going to be, and this is really

00:08:29.244 --> 00:08:31.590
just applying the formula.

00:08:31.590 --> 00:08:34.097
It's going to be nine
times 10 to the ninth,

00:08:34.097 --> 00:08:36.675
nine times 10 to the ninth,

00:08:36.675 --> 00:08:37.882
and I'll write the units here,

00:08:37.882 --> 00:08:41.922
Newtons meter squared
over Coulomb squared.

00:08:41.922 --> 00:08:44.824
And then q one times q two,
so this is going to be,

00:08:44.824 --> 00:08:46.497
let's see, this is going to be,

00:08:46.497 --> 00:08:48.396
actually let me just write
it all out for this first

00:08:48.396 --> 00:08:49.910
this first time.

00:08:49.910 --> 00:08:53.810
So it's going to be times five times ten

00:08:53.810 --> 00:08:56.480
to the negative three Coulombs.

00:08:56.480 --> 00:09:00.148
Times, times negative one.

00:09:00.148 --> 00:09:02.704
Time ten to the negative one Coulombs

00:09:02.704 --> 00:09:04.120
and we're going to take
the absolute value of this

00:09:04.120 --> 00:09:06.837
so that negative is going to go away.

00:09:06.837 --> 00:09:10.621
All of that over, all of that over

00:09:10.621 --> 00:09:12.920
and we're in kind of the
home stretch right over here,

00:09:12.920 --> 00:09:14.569
0.5 meters squared.

00:09:14.569 --> 00:09:18.991
0.5 meters squared.

00:09:18.991 --> 00:09:21.790
And so, let's just do a
little bit of the math here.

00:09:21.790 --> 00:09:24.669
So first of all, let's look at the units.

00:09:24.669 --> 00:09:25.955
So we have Coulomb squared here,

00:09:25.955 --> 00:09:27.757
then we're going to have
Coulombs times Coulombs there

00:09:27.757 --> 00:09:29.591
that's Coulombs squared
divided by Coulombs squared

00:09:29.591 --> 00:09:31.984
that's going to cancel with that and that.

00:09:31.984 --> 00:09:34.049
You have meters squared here,

00:09:34.049 --> 00:09:35.349
and actually let me just write it out,

00:09:35.349 --> 00:09:37.356
so the numerator, in the numerator,

00:09:37.356 --> 00:09:39.367
we are going to have

00:09:39.367 --> 00:09:42.717
so if we just say nine times five

00:09:42.717 --> 00:09:44.336
times, when we take the absolute value,

00:09:44.336 --> 00:09:45.218
it's just going to be one.

00:09:45.218 --> 00:09:46.634
So nine times five is going to be,

00:09:46.634 --> 00:09:47.910
nine times five times negative...

00:09:47.910 --> 00:09:49.676
five times negative one is negative five,

00:09:49.676 --> 00:09:50.975
but the absolute value there,

00:09:50.975 --> 00:09:52.857
so it's just going to be five times nine.

00:09:52.857 --> 00:09:55.427
So it's going to be 45

00:09:55.427 --> 00:09:58.955
times 10 to the nine,

00:09:58.955 --> 00:10:02.005
minus three, minus one.

00:10:02.005 --> 00:10:04.313
So six five,

00:10:04.313 --> 00:10:07.639
so that's going to be 10 to the fifth,

00:10:07.639 --> 00:10:10.457
10 to the fifth, the Coulombs
already cancelled out,

00:10:10.457 --> 00:10:15.203
and we're going to have
Newton meter squared over,

00:10:15.203 --> 00:10:20.203
over 0.25

00:10:20.312 --> 00:10:22.562
meters squared. These cancel.

00:10:22.562 --> 00:10:24.305
And so we are left with,

00:10:24.305 --> 00:10:26.302
well if you divide by 0.25,

00:10:26.302 --> 00:10:28.183
that's the same thing as dividing by 1/4,

00:10:28.183 --> 00:10:30.458
which is the same thing
as multiplying by four.

00:10:30.458 --> 00:10:32.567
So if you multiply this times four,

00:10:32.567 --> 00:10:37.330
45 times four is 160

00:10:37.330 --> 00:10:40.677
plus 20 is equal to 180

00:10:40.677 --> 00:10:44.088
times 10 to the fifth Newtons.

00:10:44.088 --> 00:10:46.015
And if we wanted to write
it in scientific notation,

00:10:46.015 --> 00:10:48.802
well we could divide this by,

00:10:48.802 --> 00:10:51.959
we could divide this by 100
and then multiply this by 100

00:10:51.959 --> 00:10:55.456
and so you could write this as 1.80

00:10:55.456 --> 00:10:57.478
times one point...

00:10:57.478 --> 00:10:58.948
and actually I don't
wanna make it look like

00:10:58.948 --> 00:11:00.805
I have more significant
digits than I really have.

00:11:00.805 --> 00:11:03.553
1.8 times

00:11:03.553 --> 00:11:07.085
10 to the seventh,

00:11:07.085 --> 00:11:09.049
times 10 to the seventh units,

00:11:09.049 --> 00:11:11.883
I just divided this by 100
and I multiplied this by 100.

00:11:11.883 --> 00:11:12.796
And we're done.

00:11:12.796 --> 00:11:15.675
This is the magnitude of
the electrostatic force

00:11:15.675 --> 00:11:18.369
between those two particles.

00:11:18.369 --> 00:11:19.970
And it looks like it's fairly significant,

00:11:19.970 --> 00:11:21.132
and this is actually a good amount,

00:11:21.132 --> 00:11:22.711
and that's because this is
actually a good amount of charge,

00:11:22.711 --> 00:11:23.872
a lot of charge.

00:11:23.872 --> 00:11:27.354
Especially at this
distance right over here.

00:11:27.354 --> 00:11:28.933
And the next thing we have to think about,

00:11:28.933 --> 00:11:31.533
well if we want not just the magnitude,

00:11:31.533 --> 00:11:33.042
we also want the direction,

00:11:33.042 --> 00:11:34.014
well, they're different charges.

00:11:34.014 --> 00:11:36.011
So this is going to be
an attractive force.

00:11:36.011 --> 00:11:38.750
This is going to be an
attractive force on each of them

00:11:38.750 --> 00:11:42.326
acting at 1.8 times ten
to the seventh Newtons.

00:11:42.326 --> 00:11:45.368
If they were the same charge,
it would be a repulsive force,

00:11:45.368 --> 00:11:48.176
or they would repel each
other with this force.

00:11:48.176 --> 00:11:50.042
But we're done.


Triboelectric effect and charge

WEBVTT
Kind: captions
Language: en

00:00:00.351 --> 00:00:02.911
- I'm guessing that you've
had the experience of rubbing

00:00:02.911 --> 00:00:04.881
a balloon against your
hair and then when you take

00:00:04.881 --> 00:00:09.818
the balloon away from your
hair, your hair sticks up.

00:00:09.818 --> 00:00:11.200
And if you haven't had that experience,

00:00:11.200 --> 00:00:13.211
you might think about trying to lead

00:00:13.211 --> 00:00:15.568
a more rich and fun life,

00:00:15.568 --> 00:00:18.456
but I'm guessing most of
you all have done that.

00:00:18.456 --> 00:00:21.382
And you had a sense that it
had something to do with the

00:00:21.382 --> 00:00:26.034
balloon or your hair, somehow
exchanging charge or now

00:00:26.034 --> 00:00:28.810
one is going to be more positive
or negative than the other,

00:00:28.810 --> 00:00:31.825
and so now they are somehow attracted.

00:00:31.825 --> 00:00:33.206
And if you were thinking of those things,

00:00:33.206 --> 00:00:34.669
you are generally right.

00:00:34.669 --> 00:00:37.046
What you just experienced
after you rubbed the balloon

00:00:37.046 --> 00:00:40.358
on your head, and then
your hair is now attracted

00:00:40.358 --> 00:00:42.085
to the balloon, that's actually called

00:00:42.085 --> 00:00:46.697
the triboelectric effect,
let me write that down,

00:00:46.697 --> 00:00:51.697
tribo, triboelectric, electric effect.

00:00:53.523 --> 00:00:55.534
And human beings have been observing this

00:00:55.534 --> 00:00:57.891
for a long long time,
and it wasn't necessarily

00:00:57.891 --> 00:01:00.431
with balloons at birthday
parties or whatever,

00:01:00.431 --> 00:01:03.214
it's with other things, they
rub a silk cloth on a piece

00:01:03.214 --> 00:01:05.002
of glass and then they'll
see that there's some type

00:01:05.002 --> 00:01:07.623
of attraction, or they
might see that if they

00:01:07.623 --> 00:01:10.163
do that enough, one of the
objects might discharge

00:01:10.163 --> 00:01:11.829
when it touches another object.

00:01:11.829 --> 00:01:13.759
People have observed
things like lightning,

00:01:13.759 --> 00:01:16.055
where it looks like there's
some type of a buildup

00:01:16.055 --> 00:01:17.761
and some type of a potential
and then all of a sudden

00:01:17.761 --> 00:01:20.556
it discharges and you have
this lightning and then this

00:01:20.556 --> 00:01:24.588
thunder blast sound that happens too.

00:01:24.588 --> 00:01:26.640
So this is something
that humans have observed

00:01:26.640 --> 00:01:30.073
for a long long time, and
scientists or people with a,

00:01:30.073 --> 00:01:32.613
I guess you could say a
scientific mind have been trying

00:01:32.613 --> 00:01:34.767
to understand it for a long
long time, and trying to come up

00:01:34.767 --> 00:01:38.450
with a framework for what
exactly is happening.

00:01:38.450 --> 00:01:41.375
Well lucky for us, we now
have a framework for it

00:01:41.375 --> 00:01:43.549
that explains it quite well.

00:01:43.549 --> 00:01:45.540
And that framework for what is going on

00:01:45.540 --> 00:01:47.491
with that triboelectric effect,

00:01:47.491 --> 00:01:50.518
is a framework around charge.

00:01:50.518 --> 00:01:54.724
Is a framework that we
now have around charge.

00:01:54.724 --> 00:01:57.792
And this tells us, this way
of looking at the world,

00:01:57.792 --> 00:01:59.844
says look, there's some things

00:01:59.844 --> 00:02:03.054
that just have a property called charge.

00:02:03.054 --> 00:02:05.593
Some things have a positive charge,

00:02:05.593 --> 00:02:07.483
Some things have a positive
charge, and it's somewhat

00:02:07.483 --> 00:02:10.063
of an arbitrary name, we just
happen to call it positive.

00:02:10.063 --> 00:02:12.745
And some things have what we
say is an opposite charge,

00:02:12.745 --> 00:02:16.057
or a negative charge, a negative charge.

00:02:16.057 --> 00:02:18.109
We could have called
this the magenta charge,

00:02:18.109 --> 00:02:19.775
and this the green charge,
we could have called this

00:02:19.775 --> 00:02:22.680
the hippopotamus charge and
this the ostrich charge.

00:02:22.680 --> 00:02:26.232
And we could have said that
hippopotami, I believe plural

00:02:26.232 --> 00:02:29.364
for hippopotamus, they're
always attracted to ostriches,

00:02:29.364 --> 00:02:32.859
but they always repel other
hippopotami, and likewise.

00:02:32.859 --> 00:02:36.651
The like charges repel or like hippo...

00:02:36.651 --> 00:02:38.608
You get the general idea.

00:02:38.608 --> 00:02:41.453
But I'll stick to the words
that people are used to using.

00:02:41.453 --> 00:02:44.135
And so if we say something has a charge,

00:02:44.135 --> 00:02:45.079
say a positive charge,

00:02:45.079 --> 00:02:47.348
and something else has a negative charge,

00:02:47.348 --> 00:02:49.986
then in our framework
that we're setting up,

00:02:49.986 --> 00:02:53.765
these two things are going to attract.

00:02:53.765 --> 00:02:56.548
So opposite charges are going to attract,

00:02:56.548 --> 00:02:59.007
while like charges are going to repel.

00:02:59.007 --> 00:03:00.957
So if you have a positive charge,

00:03:00.957 --> 00:03:02.562
and you have a positive charge,

00:03:02.562 --> 00:03:06.097
these things are going to accelerate,

00:03:06.097 --> 00:03:08.921
are going to accelerate
away from each other.

00:03:08.921 --> 00:03:10.892
And that's not just true
for positive positive,

00:03:10.892 --> 00:03:14.996
that's also true for
negative and negative,

00:03:14.996 --> 00:03:17.170
these two things are going to repel

00:03:17.170 --> 00:03:20.766
because they are like charges.

00:03:20.766 --> 00:03:22.148
Now it's very interesting
to think about this

00:03:22.148 --> 00:03:24.545
because we are so used to
thinking in terms of charge,

00:03:24.545 --> 00:03:26.475
even you know if, especially
in kind of the world

00:03:26.475 --> 00:03:28.913
of electricity you have the
positive and negative terminal.

00:03:28.913 --> 00:03:32.388
You think of charging up
your phone or whatever else.

00:03:32.388 --> 00:03:36.288
That it seems like, we completely,
charge is just something

00:03:36.288 --> 00:03:37.995
that is fundamental about the universe,

00:03:37.995 --> 00:03:40.711
and that's true to some, that's true,

00:03:40.711 --> 00:03:43.724
but you'd have to appreciate
that these are arbitrary words

00:03:43.724 --> 00:03:46.406
and they're really just
to describe a property

00:03:46.406 --> 00:03:48.660
that we have observed in the world.

00:03:48.660 --> 00:03:51.506
And if you go down to the
atomic level, we can get to

00:03:51.506 --> 00:03:54.431
a fundamental level of where
the charge is happening.

00:03:54.431 --> 00:03:56.626
But once again, these are really models

00:03:56.626 --> 00:04:00.189
for our brain to describe,
these are frameworks and models

00:04:00.189 --> 00:04:02.761
for our brain to be able
to predict and describe

00:04:02.761 --> 00:04:04.996
what we observe in the world.

00:04:04.996 --> 00:04:06.358
But if we run with this model,

00:04:06.358 --> 00:04:08.613
we can imagine at the atomic scale,

00:04:08.613 --> 00:04:13.613
the nuclei of atoms are composed
of protons and neutrons.

00:04:15.907 --> 00:04:20.375
So if you have some
protons, and then you have

00:04:20.375 --> 00:04:24.521
some neutrons, I'll do two of
each, you have some neutrons,

00:04:24.521 --> 00:04:29.521
and based on this framework,
protons have a positive charge.

00:04:29.832 --> 00:04:31.408
Protons have a positive charge.

00:04:31.408 --> 00:04:34.192
Now once again, this convention
of calling them positive

00:04:34.192 --> 00:04:36.466
and putting a plus on it,
it's not like protons have

00:04:36.466 --> 00:04:40.145
a little plus sign
tattooed onto them somehow.

00:04:40.145 --> 00:04:41.332
We could have called
those, we could have said

00:04:41.332 --> 00:04:44.147
they have a red charge, or
we could have even said,

00:04:44.147 --> 00:04:47.113
we wouldn't of had to
even use the word charge,

00:04:47.113 --> 00:04:50.547
this is just a convention
that we have decided to use.

00:04:50.547 --> 00:04:54.062
And so we say protons have
positive charge and then,

00:04:54.062 --> 00:04:57.313
kind of buzzing around the
nucleus of an atom, you often,

00:04:57.313 --> 00:05:00.746
or usually, or often have electrons.

00:05:00.746 --> 00:05:02.514
Electrons have a lot less mass.

00:05:02.514 --> 00:05:04.484
Mass is another interesting thing.

00:05:04.484 --> 00:05:06.415
We associate mass as just,
oh this is just something

00:05:06.415 --> 00:05:09.015
that we get, we understand
it in our everyday life,

00:05:09.015 --> 00:05:13.282
but even mass, this is
just a property of objects,

00:05:13.282 --> 00:05:15.374
it's just a property of matter,

00:05:15.374 --> 00:05:17.731
and we feel like we understand
it because on our scales

00:05:17.731 --> 00:05:20.596
we understand notions of
things like weight and volume,

00:05:20.596 --> 00:05:22.831
but even mass can get quite exotic.

00:05:22.831 --> 00:05:24.526
But anyway, the whole
point of this video is

00:05:24.526 --> 00:05:26.528
not to talk about mass,
it's to talk about charge.

00:05:26.528 --> 00:05:28.478
But all of these things that
we talk about in physics,

00:05:28.478 --> 00:05:31.242
these are just properties
that will help us deal

00:05:31.242 --> 00:05:35.082
with these notions, these
behaviors in different frameworks.

00:05:35.082 --> 00:05:36.728
But anyway, let's get
back to this little atom

00:05:36.728 --> 00:05:37.601
that I was constructing.

00:05:37.601 --> 00:05:40.791
So this atom, let's say
it has two electrons,

00:05:40.791 --> 00:05:43.432
and obviously this is not drawn to scale,

00:05:43.432 --> 00:05:46.398
and each of these electrons
have a negative charge,

00:05:46.398 --> 00:05:48.207
and they're kind of jumping around here,

00:05:48.207 --> 00:05:51.478
buzzing around this nucleus of this atom.

00:05:51.478 --> 00:05:54.932
And the reason why, this
model, even going down

00:05:54.932 --> 00:05:56.923
to the atomic scale and thinking
in protons and electrons

00:05:56.923 --> 00:06:00.336
is interesting, is that it
allows us to start explaining

00:06:00.336 --> 00:06:03.993
what is happening in the
triboelectric effect.

00:06:03.993 --> 00:06:06.959
What is happening in the
triboelectric effect is when you

00:06:06.959 --> 00:06:09.661
rub that balloon on your
hair, because of the property

00:06:09.661 --> 00:06:12.160
of the balloon, the
material of the balloon,

00:06:12.160 --> 00:06:13.420
and the materials of your hair,

00:06:13.420 --> 00:06:15.350
when they come in contact and they rub,

00:06:15.350 --> 00:06:19.332
the balloon is grabbing
electrons from your hair.

00:06:19.332 --> 00:06:23.416
So the balloon is grabbing
electrons from your hair,

00:06:23.416 --> 00:06:26.687
and so it is getting
more negatively charged,

00:06:26.687 --> 00:06:28.841
it is getting more negatively charged,

00:06:28.841 --> 00:06:31.766
and your hair is getting
more positively charged,

00:06:31.766 --> 00:06:34.975
or essentially it's lost these electrons.

00:06:34.975 --> 00:06:39.975
And so when you put the
balloon now close to your hair,

00:06:40.401 --> 00:06:43.652
remember like charges repel each other,

00:06:43.652 --> 00:06:46.516
so the electrons in your
hair try to move away

00:06:46.516 --> 00:06:49.043
from these other electrons,
the negative charge tries to

00:06:49.043 --> 00:06:51.494
move away from the negative charge,

00:06:51.494 --> 00:06:52.794
and I guess you could say that

00:06:52.794 --> 00:06:57.081
the tips of your hair will
then become more positive.

00:06:57.081 --> 00:06:59.702
Are more positive and
they will be attracted,

00:06:59.702 --> 00:07:03.175
and they will be attracted to the balloon.

00:07:03.175 --> 00:07:05.410
So we can think about
what's happening in terms

00:07:05.410 --> 00:07:08.906
of transfer of electrons,
that's exactly what's happening.

00:07:08.906 --> 00:07:10.997
And so when you think
that way, it's like ok,

00:07:10.997 --> 00:07:14.838
we are scientists, this is a nice model,

00:07:14.838 --> 00:07:16.504
we can start to think about
what's happening here.

00:07:16.504 --> 00:07:18.861
This model actually explains
a whole ton of behavior

00:07:18.861 --> 00:07:22.553
that we've observed in the
universe, including things like,

00:07:22.553 --> 00:07:25.728
lightning and whatever else,
you know the static shock

00:07:25.728 --> 00:07:27.200
that you get when you
might touch a doorknob

00:07:27.200 --> 00:07:30.320
after rubbing your shoes along the carpet.

00:07:30.320 --> 00:07:32.595
But we like to start, we
like to quantify things,

00:07:32.595 --> 00:07:36.171
so we can start seeing how much they repel

00:07:36.171 --> 00:07:38.101
or how much they attract each other.

00:07:38.101 --> 00:07:41.393
And so the fundamental unit of charge,

00:07:41.393 --> 00:07:43.445
or one of the fundamental units of charge,

00:07:43.445 --> 00:07:45.862
or I guess you could say the
elementary unit of charge

00:07:45.862 --> 00:07:48.626
is defined in terms of the charge

00:07:48.626 --> 00:07:51.043
of a proton or an electron.

00:07:51.043 --> 00:07:53.330
So the fundamental, or I
guess you could say the

00:07:53.330 --> 00:07:57.504
elementary unit of charge
is denoted by the letter e,

00:07:57.504 --> 00:07:59.739
and this is the charge of a proton,

00:07:59.739 --> 00:08:04.739
this is e for elementary,
charge of proton.

00:08:05.468 --> 00:08:07.317
And the charge of an electron,
even though an electron has a

00:08:07.317 --> 00:08:10.283
much, much, much, much
smaller mass than a proton,

00:08:10.283 --> 00:08:13.209
most of the mass of an atom is

00:08:13.209 --> 00:08:14.753
from the protons and the neutrons.

00:08:14.753 --> 00:08:16.582
So an electron has a
much, much smaller mass

00:08:16.582 --> 00:08:18.227
than the protons and the neutrons,

00:08:18.227 --> 00:08:22.778
but it has the same but
opposite charge as a proton.

00:08:22.778 --> 00:08:26.090
So sometimes the convention
is to write negative e,

00:08:26.090 --> 00:08:28.508
or maybe even negative one
e, sometimes depending on

00:08:28.508 --> 00:08:30.966
whether you view this as a
kind of the actual charge

00:08:30.966 --> 00:08:32.652
or whether you view this as a unit,

00:08:32.652 --> 00:08:34.136
but here I'll view this
as the actual charge.

00:08:34.136 --> 00:08:36.797
You could view negative e as the charge,

00:08:36.797 --> 00:08:40.495
as the charge of an electron.

00:08:40.495 --> 00:08:41.897
And something that has no charge,

00:08:41.897 --> 00:08:43.908
like a neutron, we say they're neutral,

00:08:43.908 --> 00:08:48.642
and actually that is why
they are called neutrons,

00:08:48.642 --> 00:08:51.547
because they are neutral,
they don't have charge.

00:08:51.547 --> 00:08:56.547
So that right over there, that
over there is, is a neutron.

00:08:57.866 --> 00:09:00.507
Now when we start to get
on kind of a larger scale,

00:09:00.507 --> 00:09:02.559
not on a sub-atomic scale anymore,

00:09:02.559 --> 00:09:06.297
talking about electrons and
protons, the unit of charge,

00:09:06.297 --> 00:09:09.284
in general the unit of
charge that we typically use

00:09:09.284 --> 00:09:13.815
is the coulomb, is the coulomb.

00:09:13.815 --> 00:09:18.815
Coulomb, it's named for
Charles Augustin de Coulomb,

00:09:18.894 --> 00:09:21.941
so if we're talking
about the guy, and he was

00:09:21.941 --> 00:09:25.314
an 18th Century French physicist,
we would use capital C,

00:09:25.314 --> 00:09:26.553
but if we're talking about the units,

00:09:26.553 --> 00:09:31.553
we would use lowercase c,
the coulomb, the coulomb.

00:09:31.836 --> 00:09:35.818
And the coulomb is
defined, so one coulomb,

00:09:35.818 --> 00:09:38.567
let me write it right
over here, one coulomb

00:09:38.567 --> 00:09:43.055
and it uses the abbreviation
uppercase C, is equal,

00:09:43.055 --> 00:09:45.062
or I'll say approximately equal to,

00:09:45.062 --> 00:09:48.210
we're going to round here,
it's approximately equal to

00:09:48.210 --> 00:09:53.210
6.24, 6.24 times 10 to the
eighteenth e, or you could say,

00:09:55.444 --> 00:09:58.329
in magnitude wise, it's
equal to the charge

00:09:58.329 --> 00:10:02.250
of 6.24 times 10 to
the eighteenth protons,

00:10:02.250 --> 00:10:03.773
or magnitude wise,

00:10:03.773 --> 00:10:05.397
it would be the opposite if
you're talking about electrons,

00:10:05.397 --> 00:10:10.174
it would be 6.24 times 10
to the eighteenth electrons.

00:10:10.174 --> 00:10:11.515
Now if you want to go
the other way around,

00:10:11.515 --> 00:10:14.055
what is the charge of, the
magnitude of the charge

00:10:14.055 --> 00:10:16.574
of say a proton in terms of coulombs,

00:10:16.574 --> 00:10:18.341
well you would just take
the inverse of this.

00:10:18.341 --> 00:10:23.341
So you could say that e
is approximately equal to

00:10:24.030 --> 00:10:27.680
the inverse of this which is 1.60,

00:10:27.680 --> 00:10:29.390
I guess you could say
the reciprocal of this,

00:10:29.390 --> 00:10:34.390
1.60 times 10 to the negative 19,

00:10:34.981 --> 00:10:38.658
times 10 to the negative 19 coulombs.

00:10:38.658 --> 00:10:40.670
So hopefully this gives
you an appreciation for,

00:10:40.670 --> 00:10:42.702
I guess at a base level, what charge is.

00:10:42.702 --> 00:10:44.388
And in some ways it's like
it's this everyday thing,

00:10:44.388 --> 00:10:46.237
you're used to it, we're used
to dealing with electricity

00:10:46.237 --> 00:10:48.350
and we'll talk much more
about that in depth.

00:10:48.350 --> 00:10:51.255
But at some levels it is this thing,

00:10:51.255 --> 00:10:52.494
one of the mysteries of the universe,

00:10:52.494 --> 00:10:55.704
how did these two particles
know to attract each other,

00:10:55.704 --> 00:10:56.761
you know it looks like
they're at a distance,

00:10:56.761 --> 00:10:59.362
how do they immediately
exert a force on each other.

00:10:59.362 --> 00:11:02.103
how do these particles know
immediately to repel each other,

00:11:02.103 --> 00:11:03.689
it's not like they have
a wire connecting them

00:11:03.689 --> 00:11:05.233
that they're communicating somehow,

00:11:05.233 --> 00:11:07.850
or I guess once you get
to quantum mechanical,

00:11:07.850 --> 00:11:09.865
an argument can be made that
they are communicating somehow.

00:11:09.865 --> 00:11:11.670
But in our everyday,
kind of logical sense,

00:11:11.670 --> 00:11:12.941
it's like well at a distance,

00:11:12.941 --> 00:11:15.345
how do these things actually
know to repel or attract,

00:11:15.345 --> 00:11:16.717
and what is this charge anyway?

00:11:16.717 --> 00:11:18.399
You know we've put all
these names around it

00:11:18.399 --> 00:11:21.202
but to kind of help us think
about it and have a framework

00:11:21.202 --> 00:11:22.401
and predict what will happen.

00:11:22.401 --> 00:11:26.017
But do we really know
what this charge thing is.

00:11:26.017 --> 00:11:28.171
So on one level it's kind
of plain and mundane,

00:11:28.171 --> 00:11:29.756
and it deals with balloons and hair,

00:11:29.756 --> 00:11:31.340
but on another level it's this deep thing

00:11:31.340 --> 00:11:35.932
about this universe, it's
a deep property of matter

00:11:35.932 --> 00:11:40.280
that we can manipulate and we
can predict, but it is still

00:11:40.280 --> 00:11:44.926
this very fundamental and
somewhat mysterious thing.


Alleles and genes

WEBVTT
Kind: captions
Language: en

00:00:00.076 --> 00:00:01.226
- What I hope to do in this video

00:00:01.226 --> 00:00:02.506
is hopefully give you some clarity

00:00:02.506 --> 00:00:06.096
on terms you might hear
used in a fairly related way

00:00:06.096 --> 00:00:10.298
and those are the terms Gene and Allele.

00:00:10.298 --> 00:00:13.743
Gene versus Allele.

00:00:13.743 --> 00:00:15.092
So let's do a little bit of review.

00:00:15.092 --> 00:00:19.183
Let's just reorient ourselves
in the world of DNA and RNA.

00:00:19.183 --> 00:00:22.251
Let's say that this,
this yellow squiggly line

00:00:22.251 --> 00:00:25.767
is a length of, I don't know, say my DNA,

00:00:25.767 --> 00:00:28.311
and let's say this little
light section right over here,

00:00:28.312 --> 00:00:29.412
that's if we were to zoom in,

00:00:29.412 --> 00:00:31.662
and we've represented
the various base pairs.

00:00:31.662 --> 00:00:33.073
And the sequence of base pairs

00:00:33.073 --> 00:00:36.000
is really the information content in DNA,

00:00:36.000 --> 00:00:38.812
and here I've just kind of
drawn it as a, as a ladder.

00:00:38.812 --> 00:00:40.333
We know that the real structure of DNA

00:00:40.334 --> 00:00:42.131
is a is kind of this twisted ladder,

00:00:42.131 --> 00:00:43.834
this double helix.

00:00:43.834 --> 00:00:48.407
Now if we talk about this
whole yellow squiggly line,

00:00:48.407 --> 00:00:49.638
and it could be even a section

00:00:49.639 --> 00:00:51.271
of a longer yellow squiggly line,

00:00:51.271 --> 00:00:55.433
this could code for multiple
for multiple things,

00:00:55.433 --> 00:00:56.700
especially multiple proteins.

00:00:56.700 --> 00:00:58.274
So different regions of this could

00:00:58.274 --> 00:00:59.641
code for different proteins.

00:00:59.641 --> 00:01:02.375
So for example, this
section right over here

00:01:02.375 --> 00:01:05.379
could be part of this region
that I'm highlighting in blue

00:01:05.379 --> 00:01:08.372
that codes for a specific protein,

00:01:08.372 --> 00:01:11.314
and so we would call this a Gene.

00:01:11.822 --> 00:01:13.180
We would call this a Gene.

00:01:13.180 --> 00:01:14.339
This might be a protein that is involved

00:01:14.339 --> 00:01:17.064
in, I don't know, I'll make something up.

00:01:17.064 --> 00:01:18.348
It's a protein that evolved,

00:01:18.348 --> 00:01:20.169
that's involved in the immune system.

00:01:20.169 --> 00:01:24.518
Maybe, maybe this stretch, let
me do it in different color.

00:01:25.133 --> 00:01:27.949
Maybe this stretch of DNA right over here,

00:01:28.702 --> 00:01:32.208
this stretch of DNA maybe
it's a longer stretch of DNA.

00:01:32.208 --> 00:01:36.922
Maybe it codes, it codes
for a protein that's used--

00:01:36.922 --> 00:01:41.212
Maybe it's a protein that
helps regulate DNA replication.

00:01:41.212 --> 00:01:46.212
Maybe over here is another
we encode for another protein

00:01:47.107 --> 00:01:52.107
that maybe, maybe it in
some ways affects, affects

00:01:53.179 --> 00:01:54.945
the pigmentation of your skin,

00:01:54.945 --> 00:01:56.869
or the pigmentation of your eyes,

00:01:56.870 --> 00:01:59.410
and so you these stretches of DNA

00:01:59.410 --> 00:02:01.436
that code for specific things.

00:02:01.436 --> 00:02:04.450
And actually it doesn't have
to just be even for a protein.

00:02:04.450 --> 00:02:06.164
We are, we always talked about even

00:02:06.164 --> 00:02:07.946
if you do code for a protein you go

00:02:07.946 --> 00:02:11.608
from the DNA to messenger RNA,

00:02:12.131 --> 00:02:15.051
to messenger RNA and actually
go to pre-messenger RNA.

00:02:15.051 --> 00:02:16.660
That gets processed so you could

00:02:16.660 --> 00:02:18.004
actually lose some sections of it,

00:02:18.004 --> 00:02:21.572
but you go to messenger RNA
and then that messenger RNA,

00:02:22.157 --> 00:02:26.947
every three of these
base pairs is a Codon.

00:02:26.947 --> 00:02:30.202
Let me, so let's say that's one codon.

00:02:30.202 --> 00:02:33.409
One, two, three, that's another codon.

00:02:33.409 --> 00:02:35.981
One, two, three, each of those--

00:02:35.981 --> 00:02:38.001
Maybe I'll draw them next to each other.

00:02:38.725 --> 00:02:41.200
Each of of them codes for an amino acid

00:02:42.108 --> 00:02:43.929
that is kind of connected
together to form,

00:02:43.929 --> 00:02:47.037
connected together to form a protein.

00:02:47.037 --> 00:02:48.977
So that's one amino acid right over there.

00:02:48.977 --> 00:02:52.312
This could be another amino
acid right over there.

00:02:52.312 --> 00:02:55.122
We can keep going on and on and on and on.

00:02:55.122 --> 00:02:57.243
You could have another
Amino Acid right over here,

00:02:57.243 --> 00:02:59.480
and then they all bond to
each other and they're brought

00:02:59.480 --> 00:03:01.861
actually to the mRNA from a,

00:03:01.861 --> 00:03:03.870
by a functional RNA group.

00:03:03.871 --> 00:03:05.751
And so there are functional things

00:03:05.751 --> 00:03:07.639
other than proteins that
this could code for.

00:03:07.639 --> 00:03:11.553
Like tRNA, tRNA which is really helping

00:03:11.553 --> 00:03:13.918
to transport the appropriate Amino Acids

00:03:13.918 --> 00:03:18.575
to the mRNA in the Ribosomes so that you

00:03:18.575 --> 00:03:20.168
can construct these proteins.

00:03:20.169 --> 00:03:21.839
So you can have tRNA and
we've seen this before

00:03:21.839 --> 00:03:22.736
in previous videos.

00:03:22.736 --> 00:03:24.041
It's this little squiggly line,

00:03:24.041 --> 00:03:25.547
matches up the the appropriate Codon,

00:03:25.547 --> 00:03:27.978
and then puts that Amino Acid in place.

00:03:27.978 --> 00:03:31.808
You also have things like Ribosomal RNA

00:03:31.808 --> 00:03:35.614
that make up the structure
of the actual Ribosomes.

00:03:35.614 --> 00:03:37.575
So RNA doesn't have to
only play this kind of

00:03:37.575 --> 00:03:39.174
in between messenger function.

00:03:39.175 --> 00:03:41.236
It actually can play a functional

00:03:41.236 --> 00:03:43.167
or a structural role.

00:03:43.167 --> 00:03:45.636
In fact there are theories
that the earliest life,

00:03:46.113 --> 00:03:50.009
the most primitive life was
nothing but self replicating RNA

00:03:50.009 --> 00:03:52.144
and then the systems became
more, and more, and more

00:03:52.145 --> 00:03:54.709
complicated and complex
until eventually you end up

00:03:54.709 --> 00:03:56.641
with things like redwood
trees and hippopotami.

00:03:56.641 --> 00:03:59.125
Hippopotamuses, hippopotami whatever.

00:03:59.125 --> 00:04:00.826
Elephants, but whatever else,

00:04:00.826 --> 00:04:05.141
but it all started with
potentially self replicating RNA.

00:04:05.141 --> 00:04:06.255
Some people say it might
be some type of proteins

00:04:06.255 --> 00:04:07.905
are able to replicate, who knows,

00:04:07.905 --> 00:04:10.836
but RNA is definitely, is definitely

00:04:10.836 --> 00:04:13.014
an interesting character in this.

00:04:13.014 --> 00:04:17.336
So you go from Gene to
RNA, that's transcription,

00:04:17.336 --> 00:04:20.834
and then RNA to protein, to protein

00:04:21.666 --> 00:04:24.943
that is translation but sometimes
you just stop at the RNA,

00:04:24.943 --> 00:04:26.972
and the RNA by itself plays a function.

00:04:26.973 --> 00:04:28.472
That's functional RNA.

00:04:28.472 --> 00:04:29.981
So each of these Genes they can code

00:04:29.981 --> 00:04:34.272
for a type of protein or
even a functional RNA.

00:04:34.273 --> 00:04:35.271
That's what a Gene is.

00:04:35.271 --> 00:04:37.368
Now what about an Allele?

00:04:37.368 --> 00:04:41.043
When the Allele is a specific
variation of the Gene.

00:04:41.043 --> 00:04:44.819
So for example, let's
say that you look at the

00:04:44.819 --> 00:04:46.801
at the same stretch of DNA.

00:04:46.801 --> 00:04:48.733
Let's say this is my DNA and if I were

00:04:48.733 --> 00:04:50.744
to take your DNA out and if were to look

00:04:50.744 --> 00:04:52.545
on the same chromosome at the same region.

00:04:52.545 --> 00:04:53.983
We're both human beings and we have

00:04:53.983 --> 00:04:55.978
for the most part very similar DNA.

00:04:55.978 --> 00:04:58.013
So this is--

00:04:58.013 --> 00:04:59.979
Actually let me straighten it out.

00:04:59.980 --> 00:05:02.980
So, let's say this is my
DNA, a section of my DNA,

00:05:02.980 --> 00:05:04.900
and let's say this right over here,

00:05:04.900 --> 00:05:07.142
this in white is a section of your DNA,

00:05:07.142 --> 00:05:11.618
and so if we look at that
Gene, that blue Gene,

00:05:12.141 --> 00:05:13.880
that's that on my DNA.

00:05:13.880 --> 00:05:16.512
Now if we look at that
and this is the blue Gene,

00:05:16.512 --> 00:05:19.913
this is the blue Gene on your DNA.

00:05:19.913 --> 00:05:21.967
Now we're both human beings and most

00:05:21.967 --> 00:05:23.947
of our genetic material is fairly similar,

00:05:23.947 --> 00:05:28.139
but we might have variations
in how this Gene is coded.

00:05:28.139 --> 00:05:32.133
For example, you might
have or I might have

00:05:32.133 --> 00:05:36.578
a let's say, I have a
an Adenine right there,

00:05:36.578 --> 00:05:38.349
but right at that exact spot

00:05:38.350 --> 00:05:40.138
you might have a different base.

00:05:40.138 --> 00:05:42.135
You might have a, I don't know,

00:05:42.136 --> 00:05:44.804
you might have a, you might have--

00:05:44.804 --> 00:05:45.248
Actually let me just--

00:05:45.248 --> 00:05:48.308
You might have a Thymine right over there.

00:05:48.309 --> 00:05:51.735
So it's encoding for a
protein, or you know,

00:05:51.735 --> 00:05:53.501
functional RNA that's
playing the same role.

00:05:53.501 --> 00:05:55.438
Maybe it has a role in the immune system

00:05:55.439 --> 00:05:56.541
or role in your skin color

00:05:56.541 --> 00:05:58.570
or role in how your brain develops,

00:05:58.571 --> 00:06:00.601
but there's a variation.

00:06:00.601 --> 00:06:02.409
There's a variation in how it's coded.

00:06:02.409 --> 00:06:03.911
Now some of these
variations which could arise

00:06:03.911 --> 00:06:06.539
through mutations, it might
not have any impact in

00:06:06.539 --> 00:06:09.683
the function of the eventual
protein that gets constructed.

00:06:09.683 --> 00:06:12.001
You might just have a
different Amino Acid sometimes.

00:06:12.001 --> 00:06:13.770
In fact, you might not even
have a different Amino Acid

00:06:13.771 --> 00:06:15.909
because many times you
have two Codons coding

00:06:15.909 --> 00:06:17.343
for the same Amino Acid,

00:06:17.343 --> 00:06:18.434
but even in a case you might have

00:06:18.434 --> 00:06:20.169
one different Amino Acid in a protein

00:06:20.169 --> 00:06:22.459
that has 4,000 Amino
Acids it doesn't change

00:06:22.459 --> 00:06:25.474
how that protein acts or how it functions.

00:06:25.474 --> 00:06:26.937
Or sometimes it might.

00:06:26.937 --> 00:06:28.574
It might change how
that protein functions.

00:06:28.574 --> 00:06:30.634
It might change how that
protein regulates other things

00:06:30.634 --> 00:06:31.903
and whoever knows whatever else,

00:06:31.903 --> 00:06:33.961
and so you could imagine
that you have Genes.

00:06:33.961 --> 00:06:35.473
This Gene right over here.

00:06:35.473 --> 00:06:37.173
Maybe it has a role in eye color,

00:06:37.173 --> 00:06:40.453
and because of this variation
or because of other variations

00:06:40.453 --> 00:06:43.102
that show up in both cases they code

00:06:43.102 --> 00:06:45.471
for the protein that
say regulates eye color,

00:06:45.471 --> 00:06:47.512
or regulates the amount
of pigment you have,

00:06:47.512 --> 00:06:49.845
but because your variation right over here

00:06:49.845 --> 00:06:52.677
might lead or help lead--

00:06:52.677 --> 00:06:54.081
And these things are very complex,

00:06:54.081 --> 00:06:56.184
it's very seldom do you
have a gene just for this,

00:06:56.184 --> 00:06:57.809
but this might make you--

00:06:57.809 --> 00:07:00.217
especially if you have a Gene like this

00:07:00.217 --> 00:07:01.341
from both of your parents,

00:07:01.341 --> 00:07:04.376
maybe this one would go for blue eyes.

00:07:05.130 --> 00:07:07.622
Blue eyes, it somehow
helps produce blue eyes.

00:07:08.084 --> 00:07:12.037
While this, while mine somehow
helps produce brown eyes.

00:07:12.037 --> 00:07:13.669
And obviously I'd want to think about

00:07:14.132 --> 00:07:17.683
which variant of this Gene
that I get from my mother,

00:07:18.083 --> 00:07:20.313
and the variant of this Gene
that I get from my father.

00:07:20.313 --> 00:07:23.337
We all have two copies in
our regular somatic cells

00:07:23.337 --> 00:07:24.409
and our body cells.

00:07:24.410 --> 00:07:25.669
We have except for--

00:07:25.669 --> 00:07:28.058
If we think about the,

00:07:28.059 --> 00:07:29.883
xx and the xy chromosomes,

00:07:29.883 --> 00:07:31.332
the sex determining chromosomes,

00:07:31.333 --> 00:07:34.312
on all the other chromosomes
we have two copies

00:07:34.312 --> 00:07:36.000
of the same Genes.

00:07:36.000 --> 00:07:36.834
We just have two--

00:07:36.834 --> 00:07:38.844
It's just they're different variants.

00:07:38.844 --> 00:07:40.272
One variant from your mother

00:07:40.272 --> 00:07:41.635
and one variant from your father,

00:07:41.635 --> 00:07:43.873
or you could say that they
are different Alleles.

00:07:43.874 --> 00:07:46.012
So Alleles are just different variants.

00:07:46.012 --> 00:07:48.041
So these are two different Alleles.

00:07:48.041 --> 00:07:49.912
They code, they're the same Gene.

00:07:49.912 --> 00:07:52.738
They're the Gene that
somehow deals with eye color,

00:07:52.738 --> 00:07:55.966
but they're different
variations for that Gene.

00:07:55.966 --> 00:07:57.550
So the Gene you're speaking generally

00:07:57.550 --> 00:07:59.678
to that region of DNA.

00:07:59.678 --> 00:08:02.774
That region of the DNA strand that codes

00:08:02.774 --> 00:08:05.558
for some functional molecule,

00:08:05.558 --> 00:08:07.543
usually protein but it could be RNA.

00:08:07.543 --> 00:08:09.983
While the Allele is
that specific variation.

00:08:09.983 --> 00:08:12.726
That flavor of that Gene.

00:08:12.726 --> 00:08:15.421
Hopefully that helps.