Saturday, 7 January 2012


This simple experiment involves testing a variety of substances to see if they are acidic oralkalineLitmus paper is used as the indicator.
Access to small amounts of common everyday substances such as: 
• fizzy drinks
• tap water 
• de-ionised/distilled water 
• toothpaste
• shampoo 
• soap
• vinegar 
• lemon juice
a Tear each piece of litmus paper into 3 smaller pieces so that you can test at least 9 substances.
b Take one small piece of red litmus paper. Dip it into one of the substances to be tested. Repeat with a small piece of the blue litmus paper.
c Record all observations in a suitable table. Then dispose of the pieces of litmus paper in the waste bin.


If the blue Litmus paper turns red 
the red is unaffected 
then the substance is acidic.
If the red Litmus paper turns blue 
the blue is unaffected 
then the substance is alkaline.
If neither red nor the blue paper changes colour, the substance is neutral.
Students should make three lists of substances under the headings ‘acidic’, ‘alkaline’, ‘neutral’.
Encourage the students to use the terms correctly. ‘Acid’ and ‘alkali’ are nouns; the words ‘acidic’ and ‘alkaline’ are adjectives. ‘A solution of vinegar is acidic. Vinegar is an acid.’

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