The States of MatterThe States of Matter

Solids, Liquids, and GasesSolids, Liquids, and Gases

Your world is full of substances that Your world is full of substances that can be classified as solids, liquids, or can be classified as solids, liquids, or gases!gases!

To define solids, liquids, and gases, To define solids, liquids, and gases, you need to examine their properties.you need to examine their properties.

SolidsSolids What if you were to pick up a solid object, What if you were to pick up a solid object,

such as a pen or a comb, and move it from such as a pen or a comb, and move it from place to place around the room? place to place around the room?

What would you observe? Would the object What would you observe? Would the object ever change its size or shape as you moved ever change its size or shape as you moved it? it?

Would a pen become larger if you put it in Would a pen become larger if you put it in bowl? bowl?

Would a comb become flatter when you Would a comb become flatter when you place it on a table top?place it on a table top?

SolidsSolids

A solid is a state of matter that has A solid is a state of matter that has a definite volume and a definite a definite volume and a definite shape.shape.

If your pen has a volume of 6 cmIf your pen has a volume of 6 cm3 3

and a cylindrical shape then it will and a cylindrical shape then it will keep that volume and shape in any keep that volume and shape in any position and in any container.position and in any container.

Particles in a SolidParticles in a Solid The particles that make The particles that make

up a solid are packed up a solid are packed very closely together. very closely together.

Each particle is tightly Each particle is tightly fixed in one position. fixed in one position. This makes it hard to This makes it hard to separate themseparate them

Because the particles in Because the particles in a solid are packed a solid are packed tightly together and stay tightly together and stay in fixed positions, a in fixed positions, a solid has a definite solid has a definite shape and volume.shape and volume.

Are the particles in a solid completely Are the particles in a solid completely motionless?motionless?

No, not really.No, not really. The particles vibrate, meaning they move The particles vibrate, meaning they move

back and forth slightly. This motion is back and forth slightly. This motion is similar to a person running in place.similar to a person running in place.

You can think of the particles in a solid as You can think of the particles in a solid as something like a group of balls connected something like a group of balls connected by tight springs. The particles that make by tight springs. The particles that make up a solid stay in about the same position. up a solid stay in about the same position. However the individual pieces are still able However the individual pieces are still able to vibrate back and forth.to vibrate back and forth.

LiquidsLiquids A liquid is a state of matter that has no A liquid is a state of matter that has no

shape of its own, but has a definite shape of its own, but has a definite volume.volume.

Unlike a solid, a liquid takes on the Unlike a solid, a liquid takes on the shape of its container. shape of its container.

Without a container, a liquid spreads Without a container, a liquid spreads into a wide shallow puddle.into a wide shallow puddle.

However, liquids are like solids in that However, liquids are like solids in that they do not easily compress or expand. they do not easily compress or expand. If you tried to squeeze water between If you tried to squeeze water between your palms, the water might change its your palms, the water might change its shape, but its volume would not shape, but its volume would not decrease or increase.decrease or increase.

What if you have 100ml of water? If you What if you have 100ml of water? If you pour it into another container the water pour it into another container the water still fills 100 ml. It has the same volume still fills 100 ml. It has the same volume no matter the shape of the container!no matter the shape of the container!

Particles in a LiquidParticles in a Liquid The particles in a The particles in a

liquid are packed liquid are packed almost as closely as almost as closely as in a solid, therefore it in a solid, therefore it does have a definite does have a definite volume. volume.

However, the However, the particles in a liquid particles in a liquid move around each move around each other freely. other freely.

Because its particles Because its particles are free to move, a are free to move, a liquid has no definite liquid has no definite shape.shape.

ViscosityViscosity

Because particles in a liquid are free to Because particles in a liquid are free to move around each other, a liquid can flow move around each other, a liquid can flow from place to place. from place to place.

For this reason, a liquid is also called a For this reason, a liquid is also called a fluid (a substance that flows).fluid (a substance that flows).

Some liquids flow more easily than others.Some liquids flow more easily than others. Viscosity is the resistance of a liquid to Viscosity is the resistance of a liquid to

flowing.flowing.

ViscosityViscosity

Liquids with high viscosity flow slowly. Liquids with high viscosity flow slowly. Cold molasses is an example of a liquid Cold molasses is an example of a liquid

with a particularly high viscosity. with a particularly high viscosity.

Liquids with low viscosity flow quickly. Liquids with low viscosity flow quickly. Water has relatively low viscosity.Water has relatively low viscosity.

GasesGases A gas is a state of matter with no definite A gas is a state of matter with no definite

shape or volumeshape or volume Unlike solids and liquids, a gas can Unlike solids and liquids, a gas can

change volume very easily. change volume very easily. If you put a gas in a container with a top, If you put a gas in a container with a top,

the gas will spread apart or squeeze the gas will spread apart or squeeze together to fill that container. together to fill that container.

The volume and shape of a gas is the The volume and shape of a gas is the volume and shape of its container. volume and shape of its container.

Particles in a GasParticles in a Gas If you could see the If you could see the

individual particles individual particles that make up a gas, that make up a gas, you would see tiny you would see tiny particles flying at particles flying at high speeds in all high speeds in all directions. directions.

Gas particles Gas particles spread apart, filling spread apart, filling all the space all the space available to themavailable to them

Thus, a gas has Thus, a gas has neither a definite neither a definite shape nor volume.shape nor volume.

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