Page 1 - 3-LESSON NOTES-DIFF. BETW. NATURAL FIBRES FROM SYN. FIBRES
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SAI International School

                                                      Class – VII
                                               Subject – Chemistry

                                              Topic –Animal Fibres
            Sub-Topic – Differentiate Natural Wool & Silk Fibre from Synthetic Fibres

                                                    LESSON NOTES

        Lab. Activity:

        Aim:  Differentiate between woollen, silk & nylon fibre by performing


        flame test.


        Fibre                Behaviour              Smell                 Formation of ash
                             towards flame
        woollen              Burns readily          Smell of              Light and crushable
                             and curl away          burning hair.         beads
                             from flame
        Silk                 Burns readily          Smell of              Light and crushable
                             and curl away          burning hair.         beads
                             from flame
        Nylon/polyester  Catches fire                Smell of             Un crushable beads
                             easily as melt on      burning plastic
                             burning
        Cotton                Takes time to         Smell of              Soft and powdery ash
                             burns                  burning paper.



        Conclusion: Natural fibres (animal fibres) on burning gives smells of burning hair and
        plant fibres on burning gives smell of burning paper whereas artificial fibres on
        burning give the smell of burning plastics.



























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