No chemicals were used to make ice before electrical refrigeration was invented, any more than chemicals are used to make ice now: the freezing of water is a physical change, brought about by lowering its temperature.
(No chemicals; to make; ice) (a physical change; brought about; by lowering its temperature) (electrical refrigeration; was invented; ) (a physical change; by lowering; its temperature) (chemicals; are used; to make ice now) (chemicals; to make; ice; T:now)
No chemicals a physical change electrical refrigeration a physical change chemicals chemicals
to make brought about was invented by lowering are used to make
ice
by lowering its temperature
its temperature
to make ice now
ice T:now