Page 58 - Science Class 06

Colour Some materials keep their shape unchanged

Some materials are recognised by their when pressed and some do not. Most solids
colour. Water is colourless, lime is white, have their shape unchanged when pressed
turmeric is yellow, leaves are green, copper while liquids and gases do not.
sulphate is blue, red chilli is red.

Combus bility Aim : Test for smell of different

Some substances produce heat and light on materials.
burning. This property of a substance is Procedure : Take four boxes made of
called combus bility. For example, paper, thick cardboard with lids. Put some
wood, petrol, wax and hydrogen. garlic, some rose flowers, a glowing

Taste agarba and a fresh cooked vegetable in
each box. Close the lids. And call some of
Many materials are recognised on the basis
your friends. Ask them to smell each box
of tastes. Thus, we know that lime is sour,
keeping their eyes closed and then tell
sugar is sweet, salt is salty, water is tasteless
what each box holds in it. They will give
and neem-leaves are bi er. Certain substan-
you correct answers. But how have they
ces are poisonous and some chemicals are
managed to do so?
dangerous for health. So, we should be
careful in tas ng such substances. Everything
should not be tasted unknowingly or without
permission.

Duc lity

The property of duc lity allows a substance
to be drawn into wires. Such substances are
called duc le. Copper, iron, gold, silver,
aluminum, etc. are some important duc le.
The par cles of smell from each of the
Bri leness things in the box came out and mixed

Some substances are broken into pieces with the par cles of the air. When your
easily. This property of a substance is called friends tried to smell pu ng their noses
bri leness. Glass is bri le. to the boxes, the smells reached their
nostrils and they were able to iden fy the
Vola lity
contents of the boxes.
Some liquids evaporate quickly when come

in contact with the atmosphere. This Diffusion
property of a liquid is called vola lity. Diffusion means mixing of the par cles of
Hardness or So ness one material with the par cles of another
through natural movement, not by shaking
Some materials are hard and some are so .
Stone is hard while clay and plas c are so . or s rring.

58 Science-6