Physical Change

A physical change affects the appearance or state of a substance but does not change its chemical structure.

Key features:

No new substance is formed

Often reversible

Involves changes in size, shape, or state (solid, liquid, gas)

Examples in plants:

Water evaporating from leaves (transpiration)

Fruit becoming softer

Leaf folding due to touch (like in a Mimosa plant)

Chemical Change

A chemical change forms one or more new substances with different properties.

Key features:

New substance is formed

Usually irreversible

Involves a chemical reaction and energy changes

Examples in plants:

Photosynthesis (carbon dioxide and water turning into glucose and oxygen)

Fruit ripening (starch turns into sugar, color and aroma compounds are formed)

Leaf decay (decomposition by microbes)