I’ve seen these bubbles often during a light rain, but have never stopped to watch them. During a recent morning walk, I decided to stop for a bit, take a few photos, and then do some research after arriving home.
They form when a droplet from a tree leaf or the sky hits a puddle. They then start flowing downhill and burst in less than 5 seconds (yes, I timed them).
I found a website called chemistry stackexchange and it explains the phenomenon as follows:
“Bubbles consist of a gas trapped by a liquid, where the liquid has a surface tension high enough to encapsulate the gas. This gives bubbles three ingredients: the liquid, the gas, and surface tension.
The first ingredient, the liquid, is obviously the rainwater.
The second ingredient, the gas, is (also obviously) air. But what isn’t obvious is how the gas becomes entrained in the liquid. Asphalt is porous, meaning the microstructure of asphalt consists of lots and lots of tiny random tubes through the solid material.
Thanks to the capillary effect, water is sucked into those tiny tubes, and gas is forced out. This gas being forced out of the porous asphalt material and through the liquid on the surface creates bubbles.”
Although I’ll never remember all of this when/if it ever comes up in conversation, I’ll be able to say, “It’s the capillary effect – look it up”. I most enjoy pulling these tidbits out when children ask questions about such things. Having just the terms at hand makes me seem awesomely wise.
It’s been raining altogether too much here this past while. As a result, many of our streets are flooded and some people are having to pump water out of their basements.
Once again, I’m so happy that we live on the main floor of a condo building, and several feet above street level.
“The sun did not shine. It was too wet to play. So we sat in the house. All that cold, cold, wet day.”Dr. Seuss