This document describes an experiment to identify acidic, alkaline, and neutral substances using litmus paper. Students tested various liquids like oil, tea, detergent, juices, and vinegar by observing the color change in blue and red litmus paper. Acidic substances turned blue litmus paper red, while alkaline substances turned red litmus paper blue. Neutral substances did not change the color of litmus paper. The experiment allowed classification of the tested substances and observation of their distinguishing properties.

1. Theme : Investigating Materials
 Unit9:
 Acid and Alkali

2. Experiment
 Aim : To identify acidic, alkaline and
neutral substances using litmus
paper

3. Method

4. Method
 1. Work in groups. The apparatus shown in
the diagram above is set up.
 2. Some oil is put into the a petri dish.

5. Method
3. A blue litmus paper and a red
litmus paper are immersed into the
oil.
4. The change of litmus paper
colour is observed .

6. Method
 5. Then steps 1- 4 are repeated by using
chinese tea, detergent, salt solution, sugar
solution, shampoo, soft drink ,orange juice
and vinegar.
 6. Observe the condition of litmus paper.

7. Observation & Classification
Acidic Alkaline Neutral
a.
b.
c.

8. Observation & Classification
Acidic Alkaline Neutral
a. vinegar shampoo oil
b. Orange juice detergent Sugar solution
c. Soft drink Chiense tea Salt solution

9. a. State the variable below:
 i. What to change : the type of substances
 ii. What to observe: change of litmus paper

10. The properties of substance
Acidic Alkaline Neutral
sour bitter No taste
Turns the blue Turns the red Does not
litmus litmus change the
Paper to red Paper to blue colour of any
litmus paper

11. Conclusion
 The acidic substances turns the blue
litmus paper to red.
 The alkaline substance turns the red
litmus paper to blue
 The neutral substance has no reaction on
any litmus paper.

12. Let to memory and sing:
 Neutral, acidic and alkaline,
 There are properties of substances,
 Sour, bitter and no taste,
 Litmus paper can test them.
 Neutral, acidic and alkaline,
 Which make fun of our life.
(rhythem :twinkle,twinkle litter stars)