I know this is was done before but the brief thread was lacking in the nitty gritty details. Regarding these ultrasonic foggers, what exactly is going on here? I know they utilize ultrasonics to break the water up into microscopic droplets by vibrating a ceramic disc at ultrasonic frequencies, but what exactly is going on during this process? I ask because I recently bought one for MindWife because I know she’s always wanted one , so I got some jumbo deluxe model with bobbing plastic fishies in a 4-gallon tube in the stand. I was trying to figure out where the little jet of water came from, since the silver electrical thingy you submerge doesn’t have a pump. I moved it around, removed it from the water and noticed that any residual water became fog instantly when it touched the copper disc in the center, as if it was being heated or something - but if course it wasn’t. Where it began to concern me was when I put my finger in the stream of water as it produced its fog. It hurt! Not horribly, it was more on the order of an electrical shock of some kind, except it wasn’t electrical. It had that electrical burn type of feel, though my finger wasn’t burnt. (I didn’t keep it in the stream long enough to find out what prolonged exposure does) Why did it hurt? Do ultrasonic frequencies cause damage to the skin?
I cannot find anything specific, so I’m gonna throw out a WAG. I suspect the ultrasonic pulses break the water into tiny droplets, then the copper disc gives them an electrical charge to keep them apart so that they don’t just recondense.
The reason it hurts is that it’s an extremely loud ultrasonic tone, focused on a very small area. That’s what breaks up the water into the tiny droplets (and that’s why ultrasonic humidifiers leave a fine dust everywhere if you don’t use distilled water; it’s not water vapor, like with a heat-based or fan-based humidifier, it’s actual droplets of liquid water that contain all the minerals, bacteria, etc. that was in the original water). When you put your finger at the focus point of the beam, all that sonic energy turns to heat inside your finger and does very painful damage.
It also melts CDs … and when I was about 10 I found out that it melted holes in the plastic lenses of my glasses, much to my dismay when I put them back on.
That burning sensation was pretty much that: burning. The ultrasound sound waves heat up the muscle, bone, etc inside your finger. Most of the stuff under your skin does not sense heat well, so you don’t feel much warmth until the temp has risen to burning hot.