Question

which of the following is a physical change?
a burning
b melting
c rusting
d rotting

Explanation:

To determine a physical change, we recall that physical changes do not form new substances, only change the state or appearance.

• Option a (burning): Involves combustion, forming new substances (e.g., CO₂), so it's a chemical change.
• Option b (melting): Changes a substance from solid to liquid (e.g., ice to water) without forming a new substance, so it's a physical change.
• Option c (rusting): Iron reacts with oxygen and water to form rust (new substance), so it's a chemical change.
• Option d (rotting): Organic matter decomposes, forming new substances, so it's a chemical change.

Answer:

b. melting