Hi. It's Paul Andersen and this disciplinary core idea PS1A. Or it's the first
one in the physical science series. This one is on the structure and properties of matter.
What is matter? Matter is what the universe is made up of. And so this picture right here
has the four phases of matter. We have solid, ice. So that would be water in a solid form.
We've got liquid water. We have gas. There's going to be a lot of water suspended in the
air. And then we've got plasma which is high energy particles. And so that's what the universe
is made up of. Matter. What is the matter made up of? It's made of atoms. And so everything
on our planet is going to be made up of atoms. Atoms themselves are made of smaller particles,
protons, neutrons and electrons. And even those are made of smaller particles. But we're
not going to get much deeper than that. Know this. That everything on our planet is made
up of around 100 atoms. And those are organized on the periodic table. This is at a museum
in Tokyo. And what they do is they'll have hydrogen, for example, and then they're going
to show you hydrogen gas. Or a little bit of lithium metal inside here. So it's actually
a periodic table of actual elements or pure substances. And so what should your students
know. Well in the early elementary grades we should start to talk about substances and
matter. And it's good to just use both of those terms. And they should be looking at
matter. So they should be looking at metal, liquids. This is wood. This would be play-dough
which is going to be matter that's created by humans. And we should look at properties
of those. So from the beginning they should be making observations of matter. What are
some observations they could make in kindergarten for example? Well they could look at the texture
or textural observations. What does it feel like? They could look at the visual. What
is it? Metals are clearly going to be shiny versus something like clay that's not going
to be as shiny. Even oral observations. What does it sound like when we hit it? And if
safety is really really important, make sure you're doing that. Even tasting it. How is
it going to taste different if we're looking at different things. Also we want to be looking
at natural made substances versus manmade substances. And so wood for example is going
to be natural. But that play-dough I showed you just a second ago is going to be manufactured.
Also they should get this idea that matter is made up of smaller things. And we can talk
about that as a concept. And so if you know what Legos are, Legos are going to be building
blocks. But we can build those into bigger blocks. The students should start to understand
that even the Legos are made of smaller particles. But we shouldn't even talk about atoms yet.
As we move into the upper elementary grades students should understand that if we take
matter, so wood for example, and cut it into parts, it's still going to be wood. If we
cut it again it's still going to be wood. But if we keep cutting it smaller and smaller
and smaller, eventually if we could do that, it's not going to be visible anymore. Even
though we're cutting it, we can't see it. But it doesn't mean the matter is not there.
And so as we get smaller and smaller and smaller, we eventually get down to the level of atoms.
And the word atomos means from indivisible. That's where the word actually comes from.
And so your students should understand that everything is made up of these really small
particles. But even though they might beinvisible, invisible particles, it doesn't mean that
they're not there. And so we can do observations to show them invisible particles exist. And
so where are some invisible particles? Well there are some right between you and me right
now. So the air is not visible, but it doesn't mean that it's not there. So if I were to
put air inside a balloon we could clearly push on it and it's going to push back. So
that would be an experiment we could do to show that these invisible particles actually
exist or even looking at the leaves moving on the tree is evidence that shows me that
those invisible particles actually exist. As we move through elementary we should talk
about the conservation of matter. What does that mean? It means that matter in general
can't be created or destroyed. What's a really simple experiment you could do to show this?
We could use a scale and take the mass of a certain amount of water. So we could get
the mass of the water in the beaker. We could get the mass of sugar cubes. So we could take
the masses separately. And then we could dissolve the sugar cubes in the water. And if we do
that we're going to find that the mass of those two at the beginning is going to be
equal to the mass at the end. So even though we've dissolved the sugar in the water, it
hasn't gone away. Even though we can't see it, it's still there. And the matter is going
to be conserved. As we move then into middle school into the 7th, 8th kind of a grade we
should start to talk about atoms and give them names. So there are around 100 different
atoms that are going to make up all of the substances. Those atoms are organized into
molecules. Now what is a molecule? Let me know go back and look at that again. So we've
got an atom. And the atoms are going to form molecules. Molecules are just going to be
made from atoms connecting together. And so molecules can have two atoms or they can have
hundreds of atoms. Some will have thousands. Like a big protein is going to have thousands
of atoms. But they're still made up of, molecules are still made up of atoms connected together.
If we have a number of different atoms that are exactly the same, we call that a substance.
So this bar of gold right here is just made of gold. It's 250 kilograms of gold. That
would be over $13,000,000 dollars worth of gold. But it's all made of these one type
of atoms. Gold atoms. Or if we were to look at water. Water is a molecule. You can see
it's going to be hydrogen, excuse me one oxygen and two hydrogens. But it still is a pure
substance if we only have that. Because it's only one type of molecule. You should also
start to talk about phases of matter. There are gong to be three phases of matter, solid,
liquid and gas. And I'm going to shoot over to a little animation, or a little simulation
that shows you how this works. This can be found at phet. And I'll put a link in the
video description down below. So if we were to look at neon, for example and let me make
it a solid. Well what does a solid look like? This is solid neon. First of all it's going
to be really cold. 13K is 13 Kelvin which is really getting pretty close to absolute
zero. You can see that the molecules are still vibrating and moving. If I were to make that
a gas, now the molecules are going to be moving all around and bouncing off the sides. And
if I were to make it a liquid. What does a liquid look like? Well they're not just going
to be vibrating in place. They're going to be sliding past one another. And as they do
that they're going to fill the container. And the simulation is kind of slow, but eventually
what'll happen is all the liquid is going to settle on the bottom. And so what would
that look like with oxygen, or excuse me, let's go to water. What does water look like?
Well if it's a solid, it's going to form ice. It's still going to vibrate. It's still going
to move. But it's going to form these nice hydrogen bonds. As we make it a liquid, then
they'll slide past one another and it would fill up the container. And then if we make
it a gas it's going to be bouncing out throughout that whole container. And this is a cool simulation
in that we can play with it. And so let's play with this. For example, what things are
going to change us from one matter to another? Well, let's look at what happens if we start
to heat up the neons. So as we start to heat up the neon, or add heat to it, it's going
to start turning first of all into a liquid. And then if we keep heating it, it's eventually
going to turn into a gas. And so as we add temperature, then we can change it from one
phase to another. If I add some ice right now I'm going to cool it down. What's that
eventually going to become? It's eventually going to become a liquid. And then it will
become a solid if I let it sit long enough. And so temperature is one thing that can effect
the phases of matter. What's another thing that could do it is pressure. And so if I
start to apply pressure on here, I can change the phases of matter as well. But I have to
be careful. If I push too hard I'm going to explode my container. Okay. So let's go back
to talking about matter. As we move into high school then, we should really talk about the
parts of an atom. So what's an atom made up of? It's made up of a nucleus. And that nucleus
is going to have two subatomic particles in it. We're going to have protons. So those
are red here. And they're going to be positive in nature. And then we're going to have neutrons
which are going to be neutral. They don't have any kind of a charge. Those are going
to be in the nucleus and it's incredibly small. So like in a football stadium, if you think
of that as the size of an atom. If we could blow up an atom to that size the nucleus is
really only going to be about the size of a ping pong ball right in the middle on the
fifty yard line. And so again the nucleus is incredibly small. What goes around the
nucleus? What's the rest of the atom? It's mostly made of electrons. It's these clouds
of probability where the electrons may or may not exist. And those are going to be negative
in charge. And so those are the three parts of an atom. We organize the atoms that we
have identified on our periodic table. And it's organized like this. The first one is
going to be hydrogen. And then as we move to right and then down we're going to increase
the number of protons. So know that hydrogen is going to have one proton because it has
an atomic number of one. Helium was what we were just looking on the previous slide, helium
is going to have an atomic number of two. That means it has two protons. And so you
can just look anywhere on the periodic table, gold for example, at 79 we know that it has
exactly 79 protons in the nucleus. How else in the periodic table organized? Well you'll
find that it's going to have these columns. And those columns are related to properties
but they're more related to the outer electron states. In other words the electrons on the
outer level. And so there's cool things we can find. Like all of these are going to be
nobel gases. In other words these are going to be stable gases like helium, neon, argon,
krypton. You can put all of these in a tube and make a neon light. We might find if we
look here that copper, silver and gold, you know that those are all going to have similar
properties. And that's because of those electrons on the outer level. Or if we were to look
at these in this first column, hydrogen is going to be a gas. But everything else is
going to be solid. And it's going to be highly reactive. So if we mix lithium, sodium or
potassium, with water were going to get an explosion. And so again looking vertically
is going to tell us a lot about the behavior of the atoms. And that's due to their outer
electron levels. So what makes matter matter going back to what they should have talked
about in elementary school? It's going to be these electrons on the outer level. And
so why does water, excuse me, metal conduct electricity? Why is it shiny and wood not?
It has to do with those electrons on the outer level. And in fact when I'm touching my hands
together and pushing them, they're not really touching each other, it's the electrons that
are hovering kind of over each other at this really microscopic level. And so one thing
you should know is that what makes matter behave the way they do is these electrical
forces. And so they try to become stable. Stable both in their electron states outside
and then inside. So there's a term you should become familiar with called binding energy.
What does that mean? Well reactants and products are going to have different amounts of energy.
And so in a quick reaction we've got oxygen and hydrogen. And they're inherently going
to be unstable gases. And they're going to combine to form something called water. What's
a real world example of that? The Hindenburg when it started on fire the hydrogen was burning.
In other words the hydrogen was mixing with the oxygen in the air. And we got a huge amount
of energy. That energy is called binding energy. It's the difference between the energy of
an unstable molecule and one that is stable. And so this is an exorgonic reaction. We're
loosing energy. And where is that energy going? It's being released as heat and light. Now
we have to put a little spark into that. We call this activation energy. You have to put
some energy into it to get it going. But that's going to be binding energy. If we reverse
that, this is water right here that we're running electricity through. And so what we're
doing is adding energy to it. Now we're adding energy to the water and as we do that, we
can break that water back into its oxygen and hydrogen. And what's neat about this experiment
is you're going to have twice as much hydrogen, twice as much hydrogen gas because there's
going to be two atoms of hydrogen for one atom of oxygen. But we have to put energy
into the system. What's an example of that? Well leaves are doing that. They're taking
energy from light and storing it in their food. Who are they making the food for? Themselves.
They can then break that down and they can release that binding energy as energy to grow.
And so that's the structure and function of matter or properties of matter. And I hope
that was helpful.