Material and Their Properties
Everything 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.
Physical Properties of Matter
The 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 different substances
Take a 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.
Which of these dissolve more
easily in water?
Salt dissolves more quickly.
Materials 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.
What is matter made of?
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.
a tiny grain of a sugar and a salt using a magnifying glass. You will find that
sugar crystal is very different from salt.
Three states of matter
can exist in one of three main states: solid, liquid, or gas.
Solid – Material
that retains its shape and volume is called solid. Example: building, stone, tin
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
Liquid – 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.
equal amount of liquid into containers of different sizes. What do you observe?
can be poured as it has flow and take the shape of container. It takes up
space, has weight and has fixed volume.
Gas – Our
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.
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 slowly.
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.
Change in state of 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
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
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
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.
changes from one substance to another are called changes in state of matter.