Which statement describes a physical change?

• A. Ice melting into water
• B. Water boiling into steam
• C. Wood burning to ash
• D. Rust forming on iron

Answer: (A)

A physical change happens when a substance changes its form or state but stays the same substance. Ice turning into water is a classic example: solid ice becomes liquid water, but you still have water—the material hasn’t become a new substance. The change just involves energy input to break some of the rigid ice structure, and it’s reversible by freezing again. In contrast, burning wood or letting iron rust both create new substances (ash and gases from combustion, or iron oxide from rust), so they’re chemical changes. Note that boiling water into steam is also a physical change, since water changes state without becoming a new material, but melting ice is a simpler, very clear illustration.