Did you observe any change in pH after eating? What may have caused the change ?

Did you observe any precipitate in the reaction ?

Is there any change in colour ?

What do you observe by cutting an apple after sometime ?Why

Is there any change in the state of material ?

Have you observed any change when lime water is added to turmeric ?

What changes do you observe when some material is burning? What do you mean by a chemical change?

What did you observe in acid and leaf experiment ? What did you have understand regarding human digestive system from this?

What do you observe on the cut pieces of fruits and vegetables? Why do they change their colour?

Did you ever observe this phenomenon in the cinema halls?