Page 1 - H.A-2-Lab Worksheet
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SAI INTERNATIONAL SCHOOL
                                               SUBJECT: CHEMISTRY
                                                       CLASS-VII
                                                  LAB WORKSHEET
                                               TOPIC- ANIMAL FIBRES

               AIM: To differentiate natural wool and silk fibres from synthetic or artificial fibres


               MATERIALS REQUIRED:  Samples of nylon, silk, wool fabrics, forceps bunsen burner.

               METHOD: Hold the fabric one by one over the flame with the forceps. Which sample
               melts, ignites or curls? Now, touch the fibre to the tip of the flame. Does it ignite quickly
               or slowly? Remove the fibre from the flame. Does it self-extinguish, continue to burn or
               continue to glow? Describe the odour given off. Does it smell like burning hair, or does it
               smell like burning plastic? Blow the flame out. Allow the fabric to cool. Press the residue
               between your fingers. Is it hard or powdery? Describe the ash quality that remains. On
               the basis of these observations, try to list the properties of wool, silk, and synthetic
               fibres.

               OBSERVATION:

                SAMPL     MELTS/IGNITES          IGNITE           SELF-           ODOUR            HARD/
                  ES           /CURLS           QUICKLY      EXTINGUISH/         (BURNING       POWDERY
                                                   OR          CONTINUE            HAIR/
                                                SLOWLY          TO BURN/         BURNING
                                                               CONTINUE          PLASTIC)
                                                                TO GLOW
               NYLON


               SILK


               WOOL



               INFERENCE:
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