Rainfall

Rainfall is the falling of tiny water droplets from the atmosphere to the Earth's surface after the condensation of water vapor in clouds.

1. Evaporation – When the Sun heats the Earth's surface, the air becomes lighter and rises, carrying moisture into the atmosphere.
2. Cooling and Condensation – As the air rises, the temperature decreases, causing the water vapor to accumulate and reach the dew point (the temperature at which air can no longer hold moisture).
3. Cloud Formation – The accumulated water vapor condenses into tiny water droplets, forming clouds.
4. Precipitation – As condensation continues, the weight of the water droplets increases, leading to rainfall.

1. Supports plant growth by providing necessary moisture.
2. Provides water for human beings and other living organisms.
3. Helps maintain ecosystem balance and supports agriculture.

The formation of rain

Rainfall is measured by collecting water droplets falling from the atmosphere using a rain gauge. This helps determine the amount of rainfall in a specific area over a given period. Rainfall is measured in millimeters (mm).

A rain gauge consists of four main parts:

1. Funnel – Collects rain droplets and directs them into the cylinder.
2. Collecting Jar or Cylinder – Holds the collected rainwater.
3. Outer Case – Protects the collecting jar and is placed 30 cm above the ground.
4. Measuring Cylinder – Used to measure the total amount of rainfall.

1. If the collecting jar fills up before the rain stops, the water is poured into the measuring cylinder, and the jar is placed back until the rain stops.
2. The total rainfall collected within 24 hours is measured and recorded on a chart.

Rain gauge