1. Summary

    Every day, we see different types of changes around us, like day turning into night, the season changing from winter to summer, melting of ice to water, cooking of food etc.Changes take place all around us all the time. All the changes are not of the same type We get back the original substance in some, and can’t get them back in others. Changes observed around us can be classified as reversible and irreversible changes.

    Reversible Change:
    A reversible change is a change that can be undone or reversed. These changes are observed in the physical state, size and shape of the substance. A reversible change does not create a new material. Ex: Melting ice, Boiling, evaporation and condensation etc.

    Irreversible Change:
    An irreversible change is a permanent change that cannot be undone. In an irreversible change, new substances are formed. Ex. cooking , digestion of food, burning of fuel.

    Mixing of substances can also cause an irreversible change. Ex: when vinegar is mixed with bicarbonate of soda, you can observe the release of carbon dioxide gas in the form of bubbles. Again, here, we cannot get back our original substances.
    Relevance  of Reversible changes in Daily Life:

    • Working of Blacksmith.
    • Expansion and contraction of metals.
    • Fixing wooden handles on tools.
    • Fixing  metallic rim on a wooden wheel.

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5. Questions & Answers
1 . Solubilty of salt
1 Answer
3 . i have a doubt
5 Answers
5 . reversible change
2 Answers

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