Educational worksheet for students to identify physical and chemical changes in matter, featuring a science experiment illustration.

To solve this, we need to decide if each change is physical or chemical.

🔹 A physical change means the substance looks different but is still the same stuff. You can often reverse it (like melting ice → water → freeze back to ice). No new substance is made.

A chemical change means a new substance is formed. It’s usually not easy to reverse. Signs: color change, bubbles, heat, smell, rust, burning, etc.

Let’s go one by one:

1) Melting of an ice cube → Ice turns to water. Still H₂O. Just changed state. → Physical

2) Rusting of an iron nail → Iron reacts with oxygen and water to make rust (iron oxide). New substance. → Chemical

3) Burning of a piece of paper → Paper turns to ash and smoke. Can’t get paper back. → Chemical

4) Cutting a piece of paper → Still paper, just smaller pieces. → Physical

5) Boiling water → Water turns to steam. Still H₂O. → Physical

6) Baking a cake → Ingredients react (baking soda + acid, eggs cook, flour sets). New substances form. → Chemical

7) Breaking a glass → Still glass, just in pieces. → Physical

8) Tarnishing of silver → Silver reacts with sulfur in air to make black tarnish (silver sulfide). → Chemical

9) Dissolving sugar in water → Sugar molecules spread out, but still sugar. Evaporate water → get sugar back. → Physical

10) Mixing baking soda and vinegar → Fizz! Makes CO₂ gas, water, and salt. New substances. → Chemical

11) Freezing water into ice cubes → Same as #1, just reversed. Still H₂O. → Physical

12) Crushing a can → Metal is squished, but still aluminum/steel. → Physical

13) Digesting food in your stomach → Enzymes break down food into nutrients. Chemical reactions happen. → Chemical

14) Ripping a piece of cloth → Still cloth, just torn. → Physical

15) Combining hydrogen and oxygen to form water → H₂ + O₂ → H₂O. Brand new substance! → Chemical

✔ All checked. Now list answers clearly.

Final Answer:
1) Physical
2) Chemical
3) Chemical
4) Physical
5) Physical
6) Chemical
7) Physical
8) Chemical
9) Physical
10) Chemical
11) Physical
12) Physical
13) Chemical
14) Physical
15) Chemical