Objectives-
(1) Students will be able to tell about the fruits which contain citric acid
(2) They will be able to tell about use of citric acid
(3) They will be able to tell about science behind the invisible ink.
Description - In this activity first of all take a lemon and write on paper with lemon juice .
It will be invisible, but when we heat it , It becomes visible ( change into dark colour).
When you heat the lemon juice which contain citric scid (carbon compounds) break down, releasing the carbon. The released carbon reacts to oxygen in the air which makes the lemon juice turn a darker colour.