Which of the following are physical changes and which are chemical changes ?
Formation of clouds

Explanation

**Step-by-Step Solution:**

1. **Understanding the Process of Cloud Formation:**
- Cloud formation begins with the evaporation of water from the Earth's surface. This process occurs when water is heated by the sun and turns into vapor, rising into the atmosphere.

2. **Evaporation:**
- During evaporation, water changes from a liquid state to a gaseous state (water vapor). This is a physical change because the chemical composition of water (H₂O) remains the same; it is still water, just in a different state.

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