Question

Once, Paheli visited a tailor shop and brought home some cuttings of fabric to study their properties. She took two pieces and found that one of the pieces was shrinking when it was burnt with a candle. However the other did not shrink on burning. Can you help her to find out which of the two was a cotton fabric and which was a silk fabric?

Answer 1

Hint: Silk and cotton both fabrics are known as natural fiber whereas natural fibres are those fibres which we get from natural things and on the other hand those fibers which are prepared in the laboratory are known as artificial fibers.

Complete answer:
Silk is the natural fiber obtained by the insect known as silkworm and cotton is also considered as natural one as it is also obtained by nature i.e. produced from the plants. Cotton is generally soft and fluffy fiber which generally grows in a ball or protective case around the seeds of cotton plants. This fiber is a pure form of cellulose.
Silk is known as natural protein fiber and some form of this fiber can be woven into textiles. The protein fiber of silk is generally composed of fibroin and produced by certain insect larvae to form cocoons. The silk cloth generally has a shimmering appearance this is due to the structure of silk which is triangular prism.
Now from here we can say that silk contains a protein therefore it shrinks whereas cotton will not shrink.

Note:
Other than silkworm, silk is produced from many other insects like bees, wasps, ants, silverfish, beetles, fleas, flies etc. Cotton clothes are generally very light weight and absorb sweating easily so in summers we wear cotton clothes mostly.