Reversible Changes – This is when materials can be changed back to how they were before the reaction took place.

E.g. When ice melts to form water. It could be frozen back to ice again.

2. Irreversible Changes – This is when materials cannot be changed back to how they were before.

E.g. When a pice of wood is burned to form ash. It cannot be made wood again.

See the PowerPoint below for some more examples.

Reversible and Irreversible Changes

Reversible Changes:

Definition:
Reversible changes are changes that can be undone or reversed, meaning the original substances can be obtained back.

Examples:
1. Melting of ice: Ice can be melted into water by applying heat, and the water can be frozen back into ice by removing the heat.
2. Dissolving sugar in water: Sugar can be dissolved in water to form a solution, and the sugar can be obtained back by evaporating the water.
3. Inflating a balloon: A deflated balloon can be inflated with air, and the air can be released to deflate the balloon again.

Irreversible Changes:

Definition:
Irreversible changes are changes that cannot be undone or reversed, meaning the original substances cannot be obtained back.

Examples:
1. Cooking an egg: Once an egg is cooked, it cannot be changed back into a raw egg.
2. Burning paper: When paper is burned, it turns into ashes which cannot be turned back into paper.
3. Rusting of iron: When iron rusts, it forms iron oxide which cannot be converted back into iron.

Changes Around Us Study Notes:

Changes around us can be categorized into reversible and irreversible changes. Reversible changes involve processes like melting, freezing, and dissolving, where the original substances can be obtained back. On the other hand, irreversible changes involve processes like cooking, burning, and rusting, where the original substances cannot be recovered. Understanding these changes is essential in various fields of science and daily life.