Reversible changes:
Reversible changes are those changes that can be undone or reversed, meaning the original substances can be obtained again. These changes are usually physical in nature and do not result in the formation of new substances.

Examples of reversible changes:
1. Melting of ice: When ice is heated, it melts to form water. This change is reversible as the water can be frozen again to form ice.
2. Boiling of water: When water is heated, it changes into steam. This change is reversible as the steam can be cooled and condensed back into water.
3. Dissolving of sugar in water: When sugar is added to water, it dissolves to form a sugar solution. This change is reversible as the sugar solution can be evaporated to obtain solid sugar again.

Observing more examples of reversible and irreversible changes:
1. Mixing of salt and water: When salt is added to water, it dissolves to form a salt solution. This change is reversible as the salt solution can be evaporated to obtain solid salt again.
2. Stretching a rubber band: When a rubber band is stretched, it changes its shape. However, this change is reversible as the rubber band can be released to regain its original shape.
3. Melting of wax: When a wax candle is heated, the wax melts and changes its state from solid to liquid. This change is reversible as the liquid wax can be cooled and solidified again.

Conclusion:
Reversible changes are those changes that can be undone or reversed, allowing us to obtain the original substances. These changes are usually physical in nature and examples include melting of ice, boiling of water, dissolving of sugar in water, mixing of salt and water, stretching a rubber band, and melting of wax. Observing these examples helps us understand the concept of reversible changes and how they differ from irreversible changes.

A reversible change is a change that can be undone or reversed. For e.g--heating of milk-flattening of a tire. e.t.c.