Question 1Change is the law of nature and occurs in our everyday life, at all times and in all places. Differentiate between the following changes with a suitable example.(a) Desirable and undesirable change(b) Periodic and non-periodic change(c) Slow and fast change(d) Natural and man-made change(e) Reversible and irreversible change

Question

Accepted Answer

(a) Difference between desirable and undesirable change :

Desirable change	Undesirable change
Desirable changes produce good results.	Undesirable changes are unfavorable.
For example, rain bringing water to crops is a desirable change.	For example, rain causing destruction by floods is an undesirable change.

(b) Difference between periodic and non-periodic change :

Periodic change	Non - Periodic change
Changes which occur periodically at regular intervals of time.	Changes which do not occur periodically [do not repeat] at regular intervals of time.
For example, change of seasons is a periodic change	For example, change of weather is a non-periodic change.

(c) Difference between slow and fast change

Slow change	Fast change
Change which occur very slowly over days, months and years.	Change which occur very rapidly in seconds or minutes.
For example, the growth of a tree from a seed	For example, occurring of lightning.

(d) Difference between natural and man-made change

Natural change	Man-made change
Changes brought about by nature.	Changes brought by man
For example, growth in man and plants.	For example, conversion of iron to steel.

(e) Difference between reversible and irreversible change

Reversible change	Irreversible change
Changes which are temporary and can be reversed by change in conditions.	Changes which are permanent and cannot be reversed by change in conditions.
For example, melting of ice and freezing of water.	For example, burning of paper.

Physical and Chemical Changes — Question 1

Question 1