Chapter 1 – Science – 6th


As we look at our surroundings, we see a large
variety of things with different shapes, sizes
and textures. Everything in this universe is
made up of material which scientists have
named “matter”. The air we breathe, the food
we eat, stones, clouds, stars, plants and
animals, even a small drop of water or a
particle of sand – every thing is matter. We
can also see as we look around that all the
things mentioned above occupy space and
have mass. In other words, they have both
mass* and volume**.
Since early times, human beings have
been trying to understand their surroundings.
Early Indian philosophers classified matter in
the form of five basic elements – the
“Panch Tatva”– air, earth, fire, sky and water.
According to them everything, living or nonliving,
was made up of these five basic
elements. Ancient Greek philosophers had
arrived at a similar classification of matter.
Modern day scientists have evolved two
types of classification of matter based on their
physical properties and chemical nature.
In this chapter we shall learn about
matter based on its physical properties.
Chemical aspects of matter will be taken up
in subsequent chapters.

1.1 Physical Nature of Matter


For a long time, two schools of thought prevailed

regarding the nature of matter. One school

believed matter to be continuous like a block

of wood, whereas, the other thought that matter

was made up of particles like sand. Let us

perform an activity to decide about the nature

of matter – is it continuous or particulate?

Activity ______________ 1.1

• Take a 100 mL beaker.

• Fill half the beaker with water and

mark the level of water.

• Dissolve some salt/ sugar with the help

of a glass rod.

• Observe any change in water level.

• What do you think has happened to

the salt?

• Where does it disappear?

• Does the level of water change?

In order to answer these questions we

need to use the idea that matter is made up

of particles. What was there in the spoon, salt

or sugar, has now spread throughout water.

This is illustrated in Fig. 1.1.

Activity ______________ 1.2

• Take 2-3 crystals of potassium

permanganate and dissolve them in

100 mL of water.

* The SI unit of mass is kilogram (kg).

** The SI unit of volume is cubic metre (m3). The common unit of measuring volume is

litre (L) such that 1L = 1 dm3, 1L = 1000 mL, 1 mL = 1 cm3.