Science, Technology, and Society LET REVIEWER
General Education
Lesson 28
States of Matter
Have you ever wondered why ice, water, and steam are all made of the same thing but look and behave so differently? The answer lies in understanding the states of matter. Everything around you, the chair you are sitting on, the water you drink, the air you breathe, is made of matter, and that matter exists in different states depending on how much energy its tiny particles have. Learning about the states of matter is one of the most foundational topics in science, not just because it appears in classroom exams and the LET board exam, but because it explains the physical world around you every single day. By the end of this lesson, you will see the world differently, because you will understand why things look, feel, and behave the way they do.
Solid
Let us
start with the state of matter that you are most familiar with. A solid
is a state of matter that has a definite shape and a definite volume.
This means that a solid keeps its own shape no matter where you put it, and its
size does not change either. The reason for this is all about the particles
inside it. In a solid, the particles are tightly packed together, almost
like people standing shoulder to shoulder in a very crowded room. They are so
close to each other that they cannot move around freely.
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| Image from BBC |
Now,
this does not mean the particles are completely still. They actually vibrate
in place, like someone standing still but shaking slightly. They do not
travel from one spot to another; they just wiggle right where they are. This
also means that solid particles have very little energy compared to
other states of matter. The less energy particles have, the closer they stay to
each other, and the more rigid the material becomes.
Example:
Think about a wooden dining table. No matter where you place it, whether in your bedroom or outside in the garden, it keeps the same shape and the same size. You cannot pour it into a container, and it does not expand to fill a room. The particles that make up the wood are locked tightly together, vibrating in place but never actually moving away from each other. That is why the table feels hard and keeps its form.
A solid keeps its own shape and size because its particles are packed tightly and only vibrate without moving around. It has the least energy among the common states of matter.
Liquid
Now
that you understand solids, let us move to something a little more
free-flowing. A liquid has a definite volume, meaning it always
takes up the same amount of space, but it does not have a definite shape.
Instead, it takes the shape of whatever container you pour it into. This
happens because the particles in a liquid are loosely packed compared to
a solid. They are still close to each other, but they are not locked in place.
They can flow around each other, sliding and slipping past one another
freely.
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| Image from BBC |
Because
liquid particles can move around, they have a medium level of energy,
which is more than a solid but less than a gas. This is why liquids can be
poured and can flow, but they cannot just fly off into the air on their own at
room temperature. They stay together as a group while still being flexible
enough to change shape.
Example:
Think about a bottle of cooking oil. When the oil is inside the bottle, it takes the shape of the bottle. But when you pour it into a frying pan, it spreads out and takes the shape of the pan. No matter what container it is in, the total amount of oil stays the same. It does not get more or less. The particles of the oil are flowing around each other, which is why it pours smoothly and does not hold one fixed shape.
A liquid always has the same amount (volume) but changes shape depending on its container. Its particles have medium energy and can move around each other, which is why liquids can flow.
Gas
After
liquid, we move to an even more energetic state. A gas does not have a definite
shape and does not have a definite volume. This means a gas will
spread out to fill up the entire space of whatever container it is placed in.
If you release a gas into a large room, it will slowly fill the whole room.
This happens because the particles in a gas have a lot of energy and
move freely and rapidly in all directions. They are spread far apart
from each other with lots of empty space between them.
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| Image from BBC |
Unlike
solids and liquids, gas particles are not really attracted to each other in a
way that keeps them together. They bounce off each other and off the walls of
any container they are in. This is also why gases can be compressed, meaning
you can squeeze them into a smaller space, because there is so much empty space
between the particles.
Example:
Imagine opening a bottle of perfume in your bedroom. You spray it near your desk, but within a few minutes, you can smell it on the other side of the room, and even people outside the door might catch a whiff of it. The perfume particles, now in gas form, are moving rapidly in every direction and spreading throughout the entire room. They do not stay in one spot. They fill all available space because gas particles have high energy and move freely.
A gas has no fixed shape and no fixed volume. Its particles move very fast and spread out to fill any space available. Gas particles have the most energy among the three common states of matter.
Plasma
Here
is where things get really interesting. Most people grow up learning about only
three states of matter: solid, liquid, and gas. But there is a fourth state
that many people do not know about, and it is actually the most common state
of matter in the entire universe. This fourth state is called plasma.
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| Image from Access Virtual Learning |
Plasma is
sometimes described as a superheated gas. It forms when a gas is heated
to an extremely high temperature, so high that the atoms start to break apart.
When this happens, the electrons (tiny particles that normally orbit
around the center of an atom) get separated from the nuclei (the center
of the atom). This creates a mix of free electrons and nuclei moving around
together. Because of this, plasma can conduct electricity, which regular gas
cannot do.
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| Image from UCAR |
You
might think plasma is something you would only find in a science lab, but it is
actually all around you in nature. The sun and other stars are made of
plasma. Lightning bolts are plasma. Even the northern lights, or Aurora
Borealis, involve plasma interacting with Earth's atmosphere. Here on Earth, we
also use plasma in neon signs and in plasma television screens.
Example:
The next time there is a thunderstorm, look at a lightning bolt. That bright, glowing flash is actually plasma. The extreme heat generated by the electrical discharge is so powerful that it tears apart the air particles, separating electrons from their nuclei for a brief moment. That is why lightning glows so brightly and why it is so hot, reaching temperatures hotter than the surface of the sun in that split second.
Plasma is an extremely hot form of gas where the atoms have broken apart into free electrons and nuclei. It is the most common state of matter in the universe and can be seen in stars, lightning, and neon lights.
Bose-Einstein Condensate (BEC)
If
plasma is about extreme heat, then this fifth and final state of matter is
about the complete opposite: extreme cold. The Bose-Einstein
Condensate, or BEC for short, is a state of matter that forms when
certain particles are cooled to temperatures incredibly close to absolute
zero, which is approximately negative 273.15 degrees Celsius. At this
temperature, matter barely has any energy at all.
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| Image from Science Direct |
The
BEC was first predicted by two scientists named Satyendra Nath Bose and Albert
Einstein in the 1920s, but it was not created in a laboratory until 1995,
when scientists finally had the technology to cool matter down to such extreme
temperatures. What happens in a BEC is fascinating: the particles slow down so
much that they stop behaving as individual separate particles and instead begin
to act as one single combined particle. It is like many separate people
suddenly merging into one body and moving together as a unit.
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| Image from Science Alert |
The
BEC does not exist anywhere naturally on Earth because our environment is far
too warm. Scientists create it in special labs using lasers and magnetic traps
to cool tiny groups of atoms to near absolute zero. While it may sound like
something only scientists care about, BEC research is important because it
helps us understand quantum physics, the science of how very tiny
particles behave, and it has potential applications in future technologies.
Example:
Imagine you have a classroom of 30 students and each student is walking around doing their own thing, going wherever they want. Now imagine the temperature drops so extremely low that all 30 students freeze completely and then somehow merge into one single being that moves together as one. That is a simplified way of thinking about what happens in a Bose-Einstein Condensate. The particles lose so much energy that they collapse into a single quantum state and behave as one unified particle rather than separate individual ones.
A Bose-Einstein Condensate is a state of matter that forms at near absolute zero temperature. At this extreme cold, particles lose almost all their energy and begin to behave as one single particle instead of many separate ones.
All Five States of Matter
