Tidbit #13 - April 8, 2011

The sound of rain is among the most beautiful sounds in our world. People love to sit inside with all the lights off and listen to its beautiful sound. However, some people like to utilize it to have a pool right outside the house, and they run out with a swimsuit on to dance around in it. They're probably having too much fun to wonder why it doesn't hurt them, falling 10,000 feet from the sky.

When you think about it, the question can be quite confusing,

Question: Why doesn't rain hurt?


Answer: Only one true answer, straight and simple:

                 Quoted: "For the same reason that a person jumping out of an airplane at 20,000 feet doesn't hit the ground with the same speed as a person jumping out of a plane at 10,000 feet. A falling object's speed continues to increase (because of the force of gravity) until the force of air resistance exactly cancels gravity. This occurs at a speed called the 'terminal velocity' for that object and depends on the object's mass and shape. That's why snow falls much more slowly than rain and why a feather falls slower than a rock with the same mass. The terminal velocity for a person is about 120 MPH." (Re: newton.dep.anl.gov)

                 Summarized: When a raindrop is released from a cloud, the force of gravity will pull it downwards, increasing its speed. The reason the speed doesn't increase indefinitely until it reaches an object that will stop it is because all the time it's falling, the air is pushing back on it, increasing the pressure at which it pushes all the time gravity pushes it down. Eventually, this "struggle" between gravity and air will equalize, and the rain will continue to fall, but it will not speed up, causing it to hit you softly with its pitter patter.

So, what do we have as a condensed summary?

When rain falls, the force of gravity and air pressure equalize its velocity, keeping it from traveling faster than the speed we know it to fall.