and Their Properties
that we see around us is made up of material. Material is the substance or
substances of which a thing is made or composed such as metal, wood, plastics,
glass and fabrics. Each material is made up matter, matter is a physical
substance which occupies space and has some weight.
Properties of Matter
properties of matter refer to the qualities/attributes that distinguish one
sample of matter from another.
Look – How do you recognize anything?
We usually see its size, shape, position and feature to recognize a particular
Feel – Touch an iron rod, a piece of
paper and a plastic bag. What do you observe? Do they feel different? Yes,
object made of different material feel different.
Smell – Smell hair oil, cooking oil and
kerosene. Do they smell same? No, each of these has a unique smell, which helps
us to distinguish them.
Taste – Every material differ in taste.
Example: sugar tastes sweet, salt taste salty, lemon taste sour. We must be
careful while tasting anything as it could poisonous such as lead, mercury etc.
Density- We may have observed that things
of same size have different weights, like feather, a sponge or a wood. This is
because the material out of which the object is made, are packed more densely
or closely than other.
Solubility – It describes how well a
substance dissolves in another substance. Solubility is a measure of how easily
the substance dissolves in water.
Experiment: Measuring the solubility of
piece of wood, 1 spoon of salt and 1 spoon of sugar in three different
containers. Pour water in all the three containers. Stir them.
of these dissolve more easily in water?
dissolves more quickly.
that dissolve in water are called soluble
substances. Example: sugar, salt, milk powder etc. Materials that do not
dissolve in water are called insoluble
substances. Example: wood, stone etc.
is matter made of?
Matter is made up of tiny particles called molecules.
Molecule is a group of atoms bonded together. Atoms are so small, that they
cannot be seen by naked eye. The molecules of every substance are different
from the molecules of any other substance.
Observe a tiny grain of a sugar and a salt using a
magnifying glass. You will find that sugar crystal is very different from salt.
states of matter
Matter can exist in one of three main states: solid,
liquid, or gas.
that retains its shape and volume is called solid. Example: building, stone, tin
A solid's particles are packed closely together.
Particles cannot move freely; they can only vibrate. As a result, a solid has a
stable, definite shape and a definite volume.
Material that does not retain its fixed shape is called liquid. Liquid matter
is made of more loosely packed particles. It will take the shape of its
container. Particles can move about within a liquid, but they are packed
densely enough that volume is maintained.
Pour equal amount of liquid into containers
of different sizes. What do you observe?
Liquid can be poured as it has flow and take the shape
of container. It takes up space, has weight and has fixed volume.
atmosphere contains a large mixture of gases, which occupy much of the space
around the globe. Gaseous matter is
composed of particles packed so loosely that it has neither a defined shape nor
a defined volume. It assumes the shape and volume of its container. Gas can
flow and expands to fill all the space available to it. A gas can be
compressed. When gas is compressed, its molecules have to huddle together.
Pretty soon they're bonding to form a liquid. Further compression will lock
them together tightly to make a solid.
When a sample of matter in the gaseous state is heated,
the atoms or molecules gain energy and move more rapidly. When a sample of
gaseous matter is cooled, the atoms or molecules lose energy and move more
Try to lift a cylinder filled with gas and then lift an empty cylinder at home.
What do you observe? It is difficult to lift a cylinder filled with gas than an
empty cylinder. This shows gas has weight.
in state of matter
Matter changes its form under certain conditions, like
heating or cooling.
When we take out ice cubes from freezer,
they are hard and solid. After a few minutes, it starts melting and turns into
a liquid. Why is it so?
Matter changes its state from solid to liquid or to a
gas because of the change in their molecules. Heating can change solids into
liquids or gases. On heating temperature rises and molecules absorb heat to
become freer and move apart. Most solids melt into liquid when they are heated.
When we boil water in a kettle it changes
to vapor. Why is it so?
This happen because water molecules in the kettle
become restless on heating and move further apart and comes out from the spout
in the form of vapor. Liquid evaporates into a gas when it is heated.
On freezing water (liquid), it changes to
ice (solid). Why is it so?
On freezing water molecules give up their heat and
settle closer together. Thus liquid water becomes solid and hard. A
liquid freezes into a solid when it is cooled and a gas condenses into a liquid
when it is cooled.
These changes from one substance to another are called
changes in state of matter.