Science - Teachers Sri Lanka

Competency 3.0 : Use chemical changes suitably to fulfil necessities of life
Comptency level 3.7 :
Control burning as appropriate to the occasion
Activity 3.7 : Let us look, find out about burning
Time : 120 mts.
Copyright © 2007 National Institute of Education - Sri Lanka. All rights reserved.
Quality inputs : • Three lengh wise folded half sheet papers, so that they are
easily ignited.
• Three copies of instrutions for exploration article given in
annex 3.7.1
• Three work stations arranged according to the instructions
given in annex 3.7.2
• Demy paper and pastel
Teaching learning
Process :
Step 3.7.1 • Ignite one of the lengh wise folded papers and cut just below
the flame so that the flame is extinguished.
• Moistened the second paper up to two third of it with
coloured water. Ignite the paper at the dry end and display it
to the students.
• With the third paper leave the ignited end on a sheet and cover
it with an empty jam bottle, allow it to extinguish.
• Lead a discussion highlighting the following points.
• The flame extinguished as a result of the burning paper
being cut and removed ( combustible subtance isremoved)
• The flame extinguished as a result of the moistend part of
the paper did not reach the temperature required (Ignition
temperature) for it to burn.
• By covering with the jam bottle the supporter of combustion
(Oxygen) was prevented from reaching the burning
subtance.
• Three factors essential for conbustion are availability of a
combustible subtance, it should reach the ignition temperature
and the gas which is the supportes of combustion.
• A chemical reaction where a combutible subtance react
with a gaseous supporter of combustion liberating heat and
light is called combustiion.
• During combustion, the carbon and hydrogen in the com
bustible react with Oxygen in the air forming the products of
combustion.
• Paper is manufactured by plant materials which basically
contains carbon and hydrogen.