[Verse 1]
Riding the cumulonimbus bus
Until gravity gets the best of me
Falling 52,500 feet
To beat the street
[Chorus]
That’s how come
The bigger they come
The harder they fall
After all
[Instrumental, Guitar Solo, Drum Fills]
[Verse 2]
What’s your status
Nimbostratus?
Only 13,120 feet
What a treat
[Chorus]
That’s how come
The bigger they come
The harder they fall
After all
[Instrumental, Saxophone Solo, Piano]
[Bridge]
Luckily for me
There’s terminal velocity
’cause I’m nor sure
My brain could sustain
No… wouldn’t endure
The fact
Of the impact
[Chorus]
That’s how come
The bigger they come
The harder they fall
After all
[Instrumental, Bass, Piano]
[Outro]
The reason
The bigger they come
The harder they fall
After all
A SCIENCE NOTE
Violent Rain
Multiple factors figure into the physics of violent rain. The starting point is the moisture content of air. The Earth is warming. Warm air can physically hold more water than cool air. The warmer the air the more water vapor the air can hold (i.e. relative humidity). The capacity doubles for every ten degree Celsius warming.
One physical result is more massive raindrops. The Momentum of Rain is p = mv (p = momentum, m = mass, v = velocity.) Part of the increasing momentum is transferred to the sides and upward increasing wind turbulence, as well as updrafts. Most of the momentum is transferred upon impact. You may notice the rain bouncing higher off the streets and sidewalks. Flowing rainwater will have both increased mass and velocity.
On the ground, concrete, asphalt, solar panels, roofs, plants, animals, houses, and infrastructure will be hit with greater momentum. In the air, the increasing mass of the rain will intensify wind turbulence. Professor Paul D. Williams of the University of Reading, UK, said, “Turbulence is chaotic (chaos theory). Turbulence is known famously as the hardest problem in physics.” In their study Evidence for Large Increases in Clear-Air Turbulence Over the Past Four Decades, Prof. Williams and his team found “Climate change has caused turbulence to double in the last 40 years” and is expected to double or triple again in the next decades.
Mass and velocity are parts of a larger equation that also includes density.The combination of these variables results in an increased intensity of the flow forces (i.e. flow dynamics). Wind and water flow forces scale as the square of velocity, so as flow speeds increase (say due to more intense heating or heavier rain) the damage scales as the square of the velocity. Look at drag physics and you will see that force is proportional to density times square of velocity (v^2).
Rain falls from various altitudes in the atmosphere. The typical distance raindrops fall depends on the height of the clouds from which they originate. Here’s a breakdown of some common cloud types and their typical altitudes:
- Cumulus Clouds: Often found at altitudes of about 1,000 to 2,000 meters (3,280 to 6,560 feet).
- Stratus Clouds: Usually found between 0 to 2,000 meters (0 to 6,560 feet).
- Nimbostratus Clouds: Typically between 2,000 to 4,000 meters (6,560 to 13,120 feet), producing steady, continuous rain.
- Cumulonimbus Clouds: These can extend from 2,000 meters (6,560 feet) up to 16,000 meters (52,500 feet), often producing heavy rain, thunderstorms, and other severe weather.
Falling Speed of Raindrops
The speed at which raindrops fall depends on their size and the atmospheric conditions. Here are some key points:
- Small Droplets: Tiny droplets (0.1 mm in diameter) fall very slowly, at about 0.2 meters per second (0.7 feet per second).
- Typical Raindrops: Average raindrops (about 2 mm in diameter) fall at around 6 to 7 meters per second (13 to 15 miles per hour).
- Larger Droplets: Large raindrops (5 mm in diameter) can fall at speeds of up to 9 meters per second (20 miles per hour).
The terminal velocity of raindrops is determined by a balance between the gravitational force pulling them down and the air resistance pushing against them. Larger droplets fall faster because they have more mass and can overcome air resistance more effectively.
Factors Affecting Fall Speed
- Air Density: In denser air (at lower altitudes), raindrops fall slower due to increased air resistance.
- Wind: Horizontal wind can alter the apparent fall speed of raindrops, causing them to move at an angle.
- Raindrop Shape: Raindrops are not perfect spheres; they tend to flatten and become more oblate as they increase in size, affecting their aerodynamics and fall speed.
Example Calculation
For a raindrop falling from a typical cumulus cloud at 2,000 meters (6,560 feet):
- Time to Fall: Using an average fall speed of 6 meters per second (13.4 miles per hour), it would take approximately 333 seconds (or about 5.5 minutes) for the raindrop to reach the ground.
- Distance: The distance fallen would be the height of the cloud base (2,000 meters or 6,560 feet).
In summary, raindrops fall from various altitudes depending on cloud type and generally fall at speeds between 0.2 to 9 meters per second, influenced by factors such as droplet size, air density, and wind.