If I were to poke my finger into a socket so that it touches both terminals, logic would suggest that it is perfectly safe, as the current would take the shortest route between the terminals (through half an inch or so of my finger), and the rest of my body, vital organs, etc would be out of its path. Wouldn’t the most I could suffer be some burns to my finger?
Why then, is it so dangerous?
Don’t try this at home, kids. 
I’ve been shocked several times when I was a kid, with one finger touching both terminals. (damn plugs too hard to remove…)
It was an… interesting sensation, but I’m still alive. (yay)
It’s not exactly the most pleasent experience in the world. It’s hard to explain, but you can feel it’s AC, feeling extremely fast vibrations (because of the 60hz)
Thank god it’s AC though. If it was DC, you might not be able to let go. (or so I’ve heard)
Chances are that you would indeed be ‘safe’ if that is the right word from fatality.
Death by electric shock is usually associated with the heart either stopping or fibrillating but you could be killed or seriously injured by reflex reaction to shock such as falling off a ladder or beign thrown backward by involuntary muscular response into something unyielding.
It takes very little current to stop the heart which is why it is so dangerous but if there is no passage across it then your reaction will usually prevent fatality.
The most dangerous shocks are the ones that go through one arm and out the other followed by through one arm and out the oppsite side foot.
Arc burns are very serious injuries indeed and are the other way of being killed by electricity.
In your case you would stand an extremely good chance of losing your finger as the passage of current will cause an arc burn, imagine the arc of a welder going through it.
I should imagine this would be painful.
Do it wrong - you’ll lose an arm.
I stuck my finger in a light socket when I was about five years old. It was a three socket lamp with only two bulbs in it. The rest of my family was in the kitchen and never knew about it. I climbed up on an armchair, stuck my finger in, felt a thoroughly unpleasant pulsating sensation, ended up on the floor very quickly, and moved on to bigger and better things. No burns or anything. I’m pretty sure my older sister told me to go and do it.
If you short out a terminal with one finger, you’ll probably just burn it. The current won’t flow through your whole body.
As someone said, the real danger is grabbing one terminal with one hand, and the other terminal with your other hand. This causes the current to flow through your body.
When I took a power electronics course, the first thing they taught us is that when you’re probing a high voltage supply, keep one hand firmly behind your back, so it doesn’t accidentally touch a ground somewhere.
Your bodys resistance is also a factor. If you are sweating the resistance path will be low and more current will be drawn. I’ve been bitten several times working on electronic equipment. Damn I hate that.It hurts more in the summer when you are sweaty.
Thanks for the replies guys. Just another observation - here in Australia, household current runs at 240V AC (50 cycles). I have had two professional electricians tell me contradictory stories. One guy told me that every time you are subjected to a full “bite” of this 240V current, you may safely assume that several years have been deducted from your lifespan due to cardiac shock. The other guy told me that, if still unsure whether a wire is “live” or not after exhausting the usual tests, it is common practice in the electrical trade to simply apply the back of one’s hand to the potentially live wire. The resulting sensation, if the wire is indeed live, will be unpleasant, but not at all dangerous.
I give up.
You can buy a voltage tester for about $2.00 American.The kind with neon bulbs works for what you are doing.Or try Dick Smith for a cheap meter.
My dad tests 9V batteies (and only god knows why) with his toungue. The more pain you feel, the more juice the battery has left in it.
Well I’ve recived 240V op one arm and down the other and I’m still here to talk about it.
My Brother, showing me how his new Muli-meter worked stuck it into a wall socket. I was impressed as a twelve year old can be and went to pull it out, grasping the metal part rather than the insulated ends, one in each hand. I can report few I’ll effects but I suspect I may have been rather lucky as it could have killed me.
Due to a combination of curiosity, stupidity, and a fairly flat learning curve, my experiences with electricity have gone from medium (absent-mindedly sticking the live phone jack in my mouth while crawling under desks) to more serious (climbing on a metal water pipe to turn off a light that apparently had a short).
Requisite fun with electricity story: I was helping a friend move out of his duplex. He was messing with his dishwasher, so I stepped out onto the porch. Apparently, his head buried in the machine, he called out for me to cut the electricity, as he was planning on cutting whatever cord hardwired the dishwasher to the house. I heard a yelp and a thud – him hitting the opposite wall – and when I came in, I saw this little blue ball of electricity skitter across the greasy linoleum for seven seconds. Way cool.
(He was okay, his arm tingled for a while, but after a few beers that went away; or, rather, everything tingled equally.)
The reason for the “back of the hand” advice is safety. The muscles on the “pull up” side of your arm are stronger, so if you touch a live wire, and your arm muscles contract involuntarily, your hand will jerk away from the wire. If you used the palm side, your hand could involuntarily grab the wire, sealing your fate.
Assuming a properly-wired, standard household outlet:
Finger contacting both hot and neutral: Painful burn in finger. Different hands touching hot and neutral: Hope somebody knows CPR. Different hands touching neutral and some ground (which can be almost anything): Nothing happens. Different hands touching hot and any ground: CPR, see above.
It’s also important to note that this is assuming a properly-wired outlet, which is, in general, not a safe assumption. Far too many outlets are wired incorrectly, with the hot and neutral reversed, and I’ve even seen a couple where the ground terminal was hot.
Ack! Hot ground wires!!..
Doctor, I have a bad case of static electricity! Every time I touch my computer case I get shocked!..