Could there be other ways to bring a change?

Could there be other ways to bring a change?

There are other ways to bring about changes in substances:

• Mixing two substances together: A small amount of curd is added to warm milk which leads to conversion of that milk into curd. This is an irreversible change.

When we add a salt to water it becomes salty but this is a reversible change.

• Expansion and Contraction: In order to make tools like an axe, the ring of its iron blade is heated which allows it to expand i.e. become larger in size and then is allowed to cool down which makes it contract again i.e. become smaller in size leading to a tight fit of the handle.

• Evaporation, Condensation
• Evaporation is a phenomenon in which a substance expands due to which its shape changes.
• Condensation is a process of changing of a substance from vapour to liquid on cooling.
• For example: - If we take water in a pan and if heat it the water in the pan will start boiling.
• So liquid form of water is changing into vapour form.
• In case of evaporation a change occurs. Liquid is changing into its water vapour form.
• Also by the process of condensation water vapour changes back to its liquid form.
• So it is a reversible change.