When a wooden stick is burnt, what new products are formed?

Options

A. Coal
B. Ash
C. Heat energy
D. All of these

Explanation

### Step-by-Step Solution:

1. **Understanding the Process**: When a wooden stick is burnt, it undergoes a chemical change. This means that the original substance (wood) is transformed into new substances.

2. **Identifying the Products**: During the burning of wood, several products are formed:
- **Coal**: This is a solid residue that remains after the combustion process.
- **Ash**: This is the inorganic residue left after the organic material (wood) has been burnt.
- **Heat Energy**: This is released during the combustion process, providing warmth.

3. **Conclusion**: Therefore, when a wooden stick is burnt, the new products formed are coal, ash, and heat energy.

4. **Final Answer**: The correct answer is that burning a wooden stick produces coal, ash, and heat energy.