Rain falls from the sky because water droplets in clouds become too heavy to stay suspended.
The Journey of Rain
Here's a breakdown of how rain makes its way down:
- Cloud Formation: Clouds are initially made of tiny water droplets.
- Droplet Growth: These tiny droplets grow larger by colliding and merging with each other.
- Reaching Critical Size: Once the water droplets become heavy enough, gravity overcomes the updrafts holding them up in the cloud.
- Falling from the Sky: As stated in the reference, some droplets fall through the cloud and coalesce into raindrops on their way down. This means that as the droplets fall, they gather even more water, becoming larger and more substantial raindrops.
- Reaching the Ground: Finally, these raindrops fall to the Earth's surface as rain.
Factors Affecting Rain Drop Size
- Cloud Conditions: The temperature, humidity, and air currents within a cloud affect how quickly and how large water droplets grow.
- Air Resistance: As raindrops fall, they encounter air resistance that affects their shape and speed. Larger raindrops experience greater air resistance, which can flatten them out.
- Coalescence: As droplets fall they may merge into larger drops.
Summary
In essence, rain goes down due to gravity. The water droplets grow large enough to become too heavy to remain in the cloud, and they fall, sometimes continuing to grow on their way down.
