Hi. It’s Winter again and the static electric at my home is horrible. I already have a humidifier on and am wearing cotton clothing. I’m trying to find a solution and there’s recommendation to touch something metal first (e.g. a key) instead of being shocked by any metallic door handles — I don’t get it? wouldn’t I just be shocked by the key instead? Thanks.
In: Physics
The zap happens as you touch something. There is one point of contact where a lot of electricity flows. If you make good contact with, say, a key, and use *that* to touch doorknobs, then the spark happens between the key and the knob. Not your hand.
Not an answer, but to be helpful, and scientific.
I always just use the back on my wrist to touch (usually door knobs). The main reason static shock hurts is much it tends to happen to the tips of your fingers, which are more sensitive to pain than genitals. Getting shocked on the back of the wrist mostly feels like nothing.
When I was younger, I worked in fabrication laboratory. We had a training course on static electricity. It was interesting that for us, being in a semi-arid climate with cold weather, carpeting and with employees wearing shoes and often sweaters, static discharge destorying components was a serious concern. Meanwhile, our competitors, often based out of the Pacific Rim, with high humidity, concrete floors and commonly barefoot, really had no issues with static discharge.
In my house, I find the sweet spot is around 17% humidity. If I keep my humidifier high enough to achieve at least that humidity percent, then I don’t experience shocks. If it drops below that, light switches, door knobs, etc., become “shocking”. I suspect you may need to increase your humidity.
If you walk on a carpet, especially in low humidity while dragging your feet, you may pick up a negative charge of electrons. When you touch or even as you approach to touch an object capable of receiving the charge (discharge), the charge “jumps” creating the spark and static discharge.
While touching a key might help discharge static electricity, it may not be as effective as touching a larger conductor (like plumbing pipes). This is because the surface area of contact affects the efficiency of charge transfer. The larger the surface area, the more charge can be discharged quickly.
Plumbing pipes are often grounded, meaning they are connected to the Earth. This provides a path for excess charge to dissipate safely, which isn’t necessarily the case with a small metal object like a key.
A light switch has conductive materials, live wires (albeit insulated) and is grounded, thus can receive a significant charge.
the reason why touching the key itself won’t shock you is because the key’s capacitance is low, it can only accept so much energy before it’s at the same charge as your body, it’s so low you don’t feel it, but if you touch something that’s either larger or grounded (like a computer case), your body will completely discharge the built up static charge via an arc, and if that charge is large enough it’ll hurt
using the key to touch other things means the discharge/arc will originate from the key, the key can’t feel anything
When you use a key, the same amount of energy flows through you to the door handle, but across a large surface area (your whole fingertip) rather than at one tiny point where the arc hits you at the end of your fingertip.
To answer your question: the idea is that you use the key to touch the doorknob or whatever, so that the static discharge occurs between it and the knob, rather than between you and the knob (so you dont feel it)
However, I have a trick that is a lot easier and more convenient. I grew up in FL, and due to high humidity static shock is just not a regular thing there. Moved out to colorado mountains for college, and i HATED it. Here’s how I dealt with it, super easy: when you anticipate a static shock (touching a doorknob, closing a car door after getting out, etc) kind of close up your index finger (like you were making a fist, but only that one finger) so that the knuckle at the end of the first joint is sticking out. Then instead of just touching the thing with your hand, kind of rap/knock your knuckle against the doorknob, car door, whatever. The static discharge still occurs, but it gets completely lost in the sensory “noise” of knocking against the thing. Like you wont even notice it. At all. Then you can just open the door like normal and not feel any shock.
If youre walking down a hall or something, you can even jsut periodically tap a knuckle against a doorknob, or those little metal corner strips they have protecting corners of walls in commercial buildings and such. It’ll bleed off your static charge and again you wont notice the zap because it happens right as your knocking the knuckle.
You need a humidifier that can keep your home relative humidity around 40%. Below 30% and you’ll get zapped frequently, and even more below 20%.
Steam humidifiers that go in the duct of a forced air system handle this much better than the old water over a humidifier pad, evaporative humidification humidifier… and steam humidifiers dont have the mold problems evaporative humidifiers have.
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