Physical change vs chemical change

 Here's a clear, exam-oriented, and student-friendly comparison of chemical and physical change, perfect for Class 10 CBSE Science. It includes a definition, key differences, examples, and a summary table for quick recall and note-making.

🔁 Difference Between Physical and Chemical Change

🧪 1. Physical Change

📘 Definition:

A change in which the physical properties of a substance (like shape, size, state, or appearance) change, but the chemical composition remains the same.

✅ No new substance is formed.

🔬 2. Chemical Change

📘 Definition:

A change in which one or more new substances with different properties are formed, and the change is usually irreversible.

✅ Chemical composition changes.

📊 Comparison Table:

Property Physical Change Chemical Change
New substance formed? ❌ No ✅ Yes
Reversibility ✅ Often reversible ❌ Usually irreversible
Energy change ❌ Minimal or no energy change ✅ Involves energy change (heat, light, etc.)
Change in composition ❌ No change in chemical composition ✅ Chemical composition changes
Examples Melting ice, tearing paper, dissolving sugar Rusting iron, burning wood, cooking food

🧠 Key Exam Tip (CBSE Style Questions):

Q: Is boiling of water a physical or chemical change?
A: Physical change – No new substance is formed, only change in state.

Q: Is digestion of food a physical or chemical change?
A: Chemical change – New substances (nutrients and waste) are formed.

💡 Real-Life Examples:

Physical Change Chemical Change
Ice melting Burning candle
Water boiling Cooking rice
Breaking a glass Rusting of iron
Dissolving salt in water Curdling of milk

🎤 Closing Thought:

“Physical changes just rearrange; chemical changes recreate. That’s how we know whether something is simply transformed—or truly reborn!”

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