Can you die from testing a 9V battery on your tongue?
Also in this week's column:
- Why doesn't a hangover occur the night before?
- What issues are there for women in space?
- Why do babies always seem to have a runny nose?
Can you die from testing a 9V battery on your tongue?
Asked by Liam Johnson of Frankfurt, Germany
Here's Liam's question in full:
First the simple question: Can you die from testing a 9V battery on your tongue? I have read newspaper reports (around 1990) of a woman dying after her boyfriend used a 9V battery as sexual stimulation.
A brief look on the internet brings up a number of comments.
- Apparently there was a US sailor being trained as an electrician who killed himself by sticking the probes of an Ohmmeter through his skin to measure his internal resistance.
- There are also claims of eight people a year dying in Australia (why just Australia?) from testing batteries.
Now, the explanation I have heard as to why this is, is that in certain freak cases, the battery can make an almost direct connection to the nervous system where the nerves are close to the surface and the skin is wet, thus ionising the nerves so that they will not work correctly. Result is death.
The detractors who attempt to answer this question invariably end up quoting figures for levels of current which kill then stating that a batter cannot generate these levels of current. This basically just dodges the issue since we have a fairly specific set of circumstances and it is not claimed that the current actually kills, rather the effect of a DC potential connected directly to the nervous system.
Besides, the figures quoted are guidelines for safety and not intended to be an absolute guarantee of safety. It is also my understanding, having spoken to a number of older electrical engineers, that there were different figures quoted for lethality for DC voltages and AC voltages, with the level of DC being significantly lower than for AC. Hope you can find some information on this issue! Thank you very much for your time!
Dr Xheng Hu of the School of Electrical and Information Engineering at the University of Sydney confirms that a 9V battery does not have enough voltage to kill a person by testing it on the tongue.
He adds: "It cannot be entirely excluded however. If a person is very ill, for example, has heart problems, or has a heart pacemaker that could be disrupted, and so on, they could possibly die from testing the battery in this way. But normally it wouldn't happen."
Stephen Juan, Ph.D. is an anthropologist at the University of Sydney. Email your Odd Body questions to firstname.lastname@example.org
Neither ohm-meters nor 9V are dangerous
I am a US Sailor, that has been an electrician for 19 years. When I was a kid, I used to put 9V batteries on my tongue to check if they were good or not. A 9V battery does not push enough amps to kill you.
As a matter of fact, if you feel the need to put the contact leads of an ohm-meter into your body..... that will not kill you either.
Also, one more food for thought, many of us have played with meggers in our careers. They just give a real big jolt, but then again there is not enough amps to kill you.
A megger is similiar to the old arcade games that you would hold onto the two handles as the game would pass a small amount of voltage through and then slowly increase it till hopefully you will let go.
Well, as a resident of the Australian (some would say Penal) Colony, I can tell you the reference to 8 people dying in Australia from battery-to-the-tounge-syndrome is rubbish.
Gored by a kangaroo, eaten by a crocodile...perhaps. 9v batteries - nope!
Unless someone has a pacemaker, I believe it not to be possible regardless - except maybe if they had some seriously weird heart condition.
The method of death referred to, involving the nerves revolves around nerves becoming depolarised. When this happens to a significant extent they can not recover.
This is actually the primary method by which criminals are electrocuted (mostly still in the US only) in electric chairs. The secondary method is a lovely cooking of the quite a few of the internal organs beyond the temperature at which they can function (or ever function again).
The present method for electrocution in Florida is as follows:
2,300 volts, 9.5 amps, for 8 seconds; 1,000 volts, 4 amps for 22 seconds; and 2,300 volts, 9.5 amps for 8 seconds. Other states vary. Some like to cook you at 480 volts for 10-15 minutes at the end!
The actual figures vary slightly per "customer" due to differing fat levels etc which effect the resistance. It is typically acknowledged that the first zap does nor depolarise the nerves fully.
Its worth noting that those figures do NOT guarantee success. There are many instances where it has failed to do the job, and thats despite excellent saline conductors to the top of the head and a nice engineered exit path via the ankle.
As you can see it would be pretty hard for a 9v battery to come even close with a "typical" person!
The actual current needed to permanently depolarise nerves is generally agred to be around seventy-five milliamps (75/1000 of an amp), externally applied to the body causes fibrillation of the heart. One amp of current applied externally to the body is sufficient to cause the heart to stop completely.
Whats interesting is that, for example, a duracell 9v battery can peak around 200milliamps - well above the 75milliamps that can end your life. But the natural resistance of the human body is typically between 2,000 and 50,000 ohms, which massively drops the current. Its this same resistance that would likely let you get away with touching the terminals of a car battery while the engine is being started - and 200+ amps are being sucked out of the battery.
The tongue would improve that by reducing the resistance (if you remove the skin, it drops to 500ohms), but not to the extent that you would likely have enough current reaching your vitals to harm you. But in general if you wanted to really reduce the resistance, you would need to apply the shock right in the middle of your chest, quite near your heart.
By the way, a detailed account of the incident with the ohmmeter and 9v battery can be read here: http://www.darwinawards.com/darwin/darwin1999-50.html
I believe it to be an urban myth as even if he stuck them in his thumbs, there would still be considerable resistance between his thumbs and his heart. Now if he dug them deep into his nipples...that I may be able to believe! (Sort of...)
More lethal than a 9V battery
A close friend of mine, having witnessed my oral 9 volt battery testing technique, decided try it for hinself. However, he chose to test the batter in his electronic flash and, unfortunately, he wrongly identified the flash unit's capacitor as the battery. He was treated to a tongue numbing shock that lierally rendered him speachless for some time thereafter. 'Didn't kill him though <grin>, and I'd be surprisd if a 9V battery would do it either.