For Grade 9A 𝘿𝙧. 𝘿𝙪𝙖𝙖 showed the students 2 examples for chemical reaction using two experiments. The first one was (𝙩𝙝𝙚 𝙚𝙡𝙚𝙥𝙝𝙖𝙣𝙩’𝙨 𝙩𝙤𝙤𝙩𝙝𝙥𝙖𝙨𝙩𝙚), it is an example of exothermic reaction and gas production, the 2nd experiment was about color change and the change of state of matter. By using solid iodine, the students had the unique opportunity to observe the change of color from silver to purple as a clue for chemical reaction.