Science High School Reviewer | Grade 4 Science | Physical Science | Properties of Matter | Lesson 24: Describing Matter

Matter is anything
that has mass and takes up space.
Most things are made of matter. The air you
breathe and the book you are reading are made
of matter. Light and heat are not matter, however.
They do not take up space.
One way to describe matter is by its properties
(PROP•uhr•teez). A property is a characteristic that
you can observe. Color, shape, and size are some
properties of matter.
Matter Has Mass
One very important property of matter is
mass. Mass is the amount of matter making up
an object. Mass is often measured in units called
grams (g) or kilograms (kg). To measure mass,
you use a tool called a balance (BAL•uhns).

Matter Has Volume
Another property of matter
is volume (VOL•yewm). Volume
is how much space an object
takes up. We measure volume by
counting the number of cubes that
can fit in an object. We can also
measure volume with tools like
graduated cylinders.
Some Properties Are Unseen
Properties that cannot be
seen can still be measured. Take
magnetism, for example. This is the
ability of matter to attract certain
metal objects.
Another unseen property is the
ability of matter to dissolve in a
liquid. When a substance dissolves,
it blends in and seems to disappear.
Sugar and salt will dissolve in
water. Sand will not.
Useful Properties
Properties help people choose the
right kinds of matter for different
jobs. When strength is needed, iron
is a good choice. Wood is better
when you need a light material that
can easily be shaped.
Buoyancy (BOY•uhn•see) is a
property that helps us build boats.
Buoyancy is the upward force of
a liquid or gas on an object. All
objects are buoyant. Some objects
are so buoyant that they float.

Solids
A solid has a definite shape and
takes up a definite amount of space.
The particles of matter in a solid
are packed together tightly. Often
the particles are packed in a regular
pattern. This textbook and your
desk are solids. What other solids
can you name?
Liquids
Orange juice is a liquid. Unlike
a solid, a liquid does not have a
definite shape. It takes the shape of
its container. However, a liquid does
take up a definite amount of space.
Consider a glass of juice. The
juice has the same volume whether it
is in a glass or a graduated cylinder.
If the juice spills, it will spread out.
Its volume stays the same.
In a liquid, the particles of matter
can move more than they do in a
solid. The particles can change place
and slide past one another. They
are farther apart than in a solid.
Water, milk, and oil are all liquids.
What other liquids can you name?

Gases
Helium (HEE•lee•uhm) is an
example of a gas. A gas does not
have a definite shape. In that way
it is like a liquid.
Unlike a liquid, a gas does not
take up a definite amount of space.
It fills the shape and space of its
container. The helium in a balloon
takes the shape of the balloon. If
the balloon bursts, the helium will
spread out into the air.
In a gas, the particles of matter
move about freely. The particles
move farther apart from one another
to fill the space around them. If there
is less space to fill, the particles are
closer together. A gas always spreads
out to fill its container.

What happens to the
matter we use?
You use matter all the time. The
food you eat is matter. Your chair is
matter. You even breathe matter!
Some matter, like air, can be used
again and again. Other forms of
matter get thrown away. Too often,
matter becomes trash. It goes into
landfills or oceans.
Many people choose to reuse
matter. This is when you use
something again instead of throwing
it away. An egg carton can be used
to plant seeds. Are there other uses
for things you throw away?
Matter can also be recycled, or
made into something else. Cans,
paper, plastic, and glass can all be
recycled. What else can you recycle?