Question

a teacher wants to perform a classroom demonstration that illustrates both chemical and physical changes. which would be the best demonstration that she could use?
○ bending a piece of aluminum
○ breaking a matchstick
○ dissolving sugar in water
○ burning a candle

Explanation:

• Bending aluminum: Only a physical change (shape alteration).
• Breaking a matchstick: Only a physical change (size reduction).
• Dissolving sugar in water: Only a physical change (state change).
• Burning a candle: Wax melting is a physical change (state from solid to liquid). Wax combustion is a chemical change (producing new substances like \(CO_2\) and \(H_2O\)).

Answer:

burning a candle