There are a plethora of methods to assessing the horrible state of mind of a person undergoing a field sobriety test. I suspect there are some stones as yet left unturned.

The idea is simple: ethanol changes the surface tension of whatever solution it's within. Bubbles have been shown to have a lifespan generally proportional to the amount of alcohol in solution (linky). So, here's what we do guys. We give the police a very well-researched bottle of blowing bubbles and this can serve as a first line of interrogation during a field sobriety test. Simply have the driver stand a specific number of feet away from the police car and have them blow the bubbles towards the car. If the driver is over the legal limit the alcohol in their breath with have a tell tale effect on the lifespan of the bubbles as it migrates from the interior of the bubble into the matrix of the bubble itself. And yep, you guessed it, if any bubbles make it to the police car and pop on the the hood, that little rascal is in trouble. And if any bubbles make it all the way over the car and pop on the roof lights? Man oh man, bad night for that sorry fella.

Now, that little circular bubble wand will absolutely be high tech and have a little canal with a flipper that measures air velocity. The canal will be aside from the main bubble canal to avoid any problems with the intricacies of the surface tension. Also, there will be a hygrometer on the wand to accurately calculate the amount of surfactant to add to the mixture to create a valid test under any atmospheric conditions. We can't have anyone cheating this test.

Also, the cop needs to set up wind socks between the driver and the cop car. Three of them to be exact. If any of the socks measure some sort of threshold windspeed, the test can be dismissed. Or they can simply wait for the wind to die down.
-- daseva, May 22 2023

Bubbles determine the amount of alcohol in Mezcal https://www.nature..../s41598-020-67286-x
proof of concept [daseva, May 22 2023]

The question that comes immediately to my mind is, what exactly do you mean by "generally proportional"? Your link says "the precise mechanism and its relation to alcohol content remain unexplained." That doesn't sound conclusive enough for legal use. The other question, of course, is are there other things in a person's system that could affect bubble longevity? Could garlic, or onions, or capsaicin on your breath, in your saliva, etc affect bubble longevity? What about cannabis? That's important to know because this test is only valid if alcohol is the ONLY thing on a person's breath that can affect the bubble longevity.
-- 21 Quest, May 22 2023


[a1], I was hoping the hygrometer would take care of the atmospherics, but any additions are more than welcome as this will be a most rigorous test. Facilitating the weather service is a nice touch. I anticipate they might get jealous and want their own bubblizers.

[21_Quest], it's proportional up to ~50% alcohol before it turns the corner. I don't think anyone is going to have a BAC @ 50% so it's safe to say "generally proportional" for our purposes.

I think you bring up some great points. It would be helpful if the driver can show receipts of whatever they ate for dinner. This might help corroborate the purported # of drinks, too.
-- daseva, May 22 2023


You had me at ethanol.
-- Voice, May 22 2023



random, halfbakery