In order to loosen a stopper from the neck of a glass bottle, boiling water is poured around the neck. Why?

Explanation

To understand why boiling water is poured around the neck of a glass bottle to loosen a stopper, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Understanding Thermal Expansion**:
- When materials are heated, they generally expand. This phenomenon is known as thermal expansion. Different materials expand at different rates depending on their properties.

2. **Application of Boiling Water**:
...