Classify the following processes into physical or chemical changes:
(i) The beating of aluminium metal to make aluminium foil.
(ii) Digestion of food.
(iii) Cutting of a log of wood into pieces.
(iv) Burning of crackers.
(i) Physical change
Beating of aluminium metal to make aluminium foil consist of a change in only shape and size.
(ii) Chemical change
Digestion of food involves various chemical reaction inside our stomach.
(iii) Physical change
Cutting off a log of wood into pieces just changes its physical properties like shape and size. Therefore, it is a physical change.
(iv) Chemical change
Crackers contains substances which are explosive and during burning explosive reaction took place. Hence, it is a chemical change.