Welcome back, fellow scientists! Justin here.
Are you ready to dive back into some matter? I was. Literally. Uh, see, yesterday I wanted to
go for a swim in my favorite pond, but when I got there, it was completely frozen. And that got me
thinking; why can't we go swimming in a frozen pond? No, I'm serious. Think about it. Ice and
water are all made up of the same stuff, right? So why is it easy to move through water, but ice is
all hard and tough? Well, to answer that question, we're going
to need to learn more about the states
of matter. By the end of today's lesson, you will be able to identify the four states of matter
and describe their properties. Let's get into it. In our last lesson, we learned that matter
is anything that has mass and volume. This means that wildly different things can all
be matter, from an aardvark to pineapple juice to the hydrogen and helium gases
that form the stars of our universe. So, as you can see, matter comes in all
sorts of shapes and si
zes - and states. What is a state? Well, state is one of
those words with more than one definition, but in this case, it means the form that matter
is in. Matter comes in four different states: solid, liquid, gas, and plasma. Each of these
states have certain properties that will tell us how the matter will behave. These properties
come from all the way down at the atomic level. Remember in the last lesson when we learned that
all matter was made up of teeny tiny atoms? Well, it's how these
atoms are arranged that
will tell us what state the matter is in. Let's take a look at solids first. A pencil, a
baseball, and the device you're currently using to watch this video are all great examples of
solids. Solids all have a definite or fixed volume and shape. Think about it this way; this rock is a
solid, right? Unless an outside force acts on it, it will always keep its same rocky size and
same rocky shape. The reason for the rock's definite shape and volume is the arrangement of
its atoms. A solid's atoms are packed extremely close together. Now, let's learn how the
atoms in a solid move by observing this rock. Fascinating. Now, you might think that solids
don't really move much - and you'd be right - but once again, if we take a much closer look, you'll
see that the atoms are actually moving. Now, the atoms are really packed tightly
together so they can't move much, but the atoms in a solid are all constantly
vibrating just a little bit. You can think of solids
like a really tightly packed elevator. The
people in the elevator are all cramped in there so they can't really move, but they're all still
kind of shuffling around just to get comfortable. So, solids have a fixed shape and volume,
their atoms are packed very closely together, and they're always vibrating. Hmm, what examples
of matter in the solid state can I think of? Well, a donut is a solid, my pencil sharpener
is a solid, and those really cool glasses that I got for the last lesson are
also a solid.
Why don't you pause the video here and jot down some of your own examples of the solids
you can see around you in your guided notes. If you've had anything to drink today then you
have already come across our next state of matter, liquid. Things like juice, syrup, oil, and lotion
are all typically in the liquid states when we use them. Liquids have a definite volume, so they
always take up the same amount of space. However, they don't have a fixed shape. If you pour
a liquid
into a cylindrical container, it will take the shape of a cylinder. Pour it into
a bear-shaped container and it'll take the shape of a bear. Liquids take the shape of whatever
container they're in. This is because the atoms in a liquid are more loosely packed than a solid.
Because the atoms are more spread out, they can move faster and they're able to slide past each
other. This is what allows a liquid to flow and be poured, like when you pour milk into your cereal
bowl. If solids are like
a crowded elevator, then liquids are kind of like a race; it's still pretty
crowded, but people are able to pass each other or fall behind and they are definitely moving
faster than those people stuck in the elevator. To recap, matter in the liquid state has a
definite volume but no definite shape. Its atoms are more loosely packed, allowing them
to move faster and slide past each other. Pause the video now and write down some
examples of liquids in your guided notes. Our next state of matt
er is gas. Gas constantly
surrounds us. We use helium gas to fill up balloons, steam gas to iron out the wrinkles
in our clothes, and of course, we all rely on the oxygen gas in the atmosphere to breathe. Gases
have no fixed volume or shape. In fact, gases will expand into whatever space is available to them,
whether that's a car's tires or an entire room. Gases behave this way because their atoms
are very spread out. The atoms are moving super quickly past each other. They're kind
of like
kids running around the playground; they're spread out, they're moving quickly
in every direction, and they might sometimes bump into each other but that doesn't happen too
often. So, gas has no definite volume or shape; its atoms are all spaced out and moving around
really quickly. Pause the video now to come up with some of your own examples of matter
in the gas state in your guided notes. Solids, liquids, and gases account for most of
the matter that we see here on Earth. However, about
99 percent of all matter in the universe is
actually in the fourth state of matter - plasma. Plasma is the outcome of adding a lot of energy
to a gas, usually in the form of heat. All that energy causes pieces of the atoms themselves
to break off, resulting in something like an electrified gas. The sun and other stars in our
universe are mostly made of plasma. However, we can see examples of plasma here on
Earth in things like lightning, fire, and the Aurora Borealis, also called the
Nort
hern Lights. There are also artificial examples of plasma here, too, like in
neon signs or fluorescent light bulbs. Now that we've explored the states of matter, let's review everything we learned today. We
now know that matter exists in four states: solid, liquid, gas, and plasma, although that
one is a lot less common to find on Earth. Each state of matter has properties that determine
how it behaves. A solid has a definite volume and a shape and its atoms are tightly packed and
slightly
vibrating. A liquid has a definite volume but not a definite shape. Its atoms are
more loosely packed and they flow past each other with more speed. And a gas has no definite
volume or shape. Its atoms are spread out, moving quickly past each other. To find out more
about the states of matter, be sure to check out the activities and practice questions that go with
this lesson. All right, that's it for me today. Thank you so much for joining us and remember,
science is all around us. See you
next time!
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