What is the purpose of a barometer ?

Answer

### Step-by-Step Solution:

1. **Definition of a Barometer**: A barometer is an instrument designed to measure atmospheric pressure.

2. **Function of a Barometer**: The primary purpose of a barometer is to provide a measurement of the weight of the air above us, which is known as atmospheric pressure.

3. **Types of Barometers**: There are various types of barometers available, including mercury barometers and aneroid barometers. The mercury barometer uses a column of mercury to measure pressure, while aneroid barometers use a sealed metal box that expands or contracts with changes in pressure.

4. **Importance of Measuring Atmospheric Pressure**: Measuring atmospheric pressure is crucial for various applications, including weather forecasting, altitude measurement, and scientific research.

5. **Conclusion**: In summary, the purpose of a barometer is to measure atmospheric pressure, which is essential for understanding weather patterns and other scientific phenomena.