Changes around us (part -1) class 6
Changes around us
Q.1. What do you understand by the term 'Change'?
Ans. When one or more properties of a thing become different. We say it has changed
or a change has taken place.
For
example:
- Formation
of curd from milk
- Cooking of
food
- Melting of
ice
- Growing of hairs and nails
- Leaves fall from trees, change colour and dry out
Q.2.
Give some examples of beneficial changes and harmful changes.
Ans. some
beneficial changes can be:
- The
ripening of fruits
- Cooking of
the food
- Formation
of curd from milk
some harmful changes can be:
- The
spoiling of food
- Rusting of
iron
- Rubbing of
soles of shoes
Q.3.
Do changes occur on their own? Give one example.
Ans. It appears that many changes are taking place around
us on their own but changes do not occur on their own. There is always a 'cause' which
brings a change. For example: heat is the cause of change in the state of ice
from solid to liquid.
Q.4.
What do we mean by reversible and irreversible changes? Give some examples.
Ans. Reversible
change:
A
change which can be reversed to form the 'original substance' is called
reversible change. For example:
- melting of
ice
- stretching
of rubber band
- dissolving
salt in water
- knitting
of sweater
- drying of
clothes
- heating of
milk
- folding of
paper or clothes
- inflating
a balloon
- shaping wet clay into clay pot
- expansion
of metals
Irreversible change:
A change which can not be reversed to form the 'original substance' is called irreversible change. For example:
- burning of paper or fuels
- plucking of flowers
- formation of curd from milk
- growth of living being
- ripening of fruit
- rusting of iron
- drawing a painting with colours and pens
- setting of cement or POP (plaster of paris) with water
- boiling of egg
- blooming of flower
