Physical and Chemical Changes

A physical change is a change in the shape, size, or state of a substance without changing its actual identity. For example, melting ice, tearing paper, or boiling water are physical changes. No new substance is formed.

A chemical change is when a substance changes into a completely new one. It involves a chemical reaction, and the original substance cannot be easily recovered. Examples include burning wood, rusting iron, or cooking food.

Key Differences:

• Physical change is usually reversible; chemical change is mostly irreversible.

• Chemical changes produce heat, gas, light, or a new color or smell.

Understanding these changes helps us know how matter behaves in everyday life.