Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Electric Charges in Humans

  1. Aug 29, 2008 #1
    hey everybody! i have an inquiry!!.......Why? and How?? people get "charged" and get self electrically shock or electroshock somebody else???.....

    let me explain myself better....for example...my mom has like 2 weeks that she gets "charged" electrically....everytime she touches something she gets electrically shocked...and even in her office the people is afraid to pass her the cell phone because when she touches them they get shocked!!......how and why does she gets to that state??....she works in an office in a computer 10hrs per day....could it be that??....

    another example...i have a friend, hes a doctor!!....once in a while he also gets electrically charged!!....for instance...when he gets out of the car and he`s gonna touch the door to close it he gets shocked with current...it like a snap....it even sounds the spark!!!......

    another example is that when my girlfriend goes to the kitchen and opens the fridge (bare footed) she gets shocked....but i have open the fridge on my bare foot even wet getting out of the shower and I DONT get shocked.....why some people gets electrically charged, WHY the get charged and how do they get shocked by the current spark?.....

  2. jcsd
  3. Aug 30, 2008 #2
    These shocks are called static electricity. They are caused by a build up of charge on your body, which can be caused by a number of things. If you don't know exactly what charge is physically, think of it like this: there are two types of charge, positive and negative. The negative charges are transferred via particles called 'electrons' (the positive charges are usually not transferred).

    A classic example: If you rub a balloon across your hair, it will 'stick' to your hair.
    Static is also common to occur if you are wearing something like wool clothing.
    And as you describe also when you get out of your car.

    Let's take the car as example. While you are driving, the wind is continuously blowing over the car. This causes a charge buildup on the outside (metal) of the car. When you stop your car and you get out of the car, there is a charge difference between your skin and the car's metal body. When you touch (or come close) to the cars body, this charge difference causes the electrons to jump from the car onto your finger (or the other way around, I don't know, but it doesn't really matter). This is the spark you hear (and can even see it it's large enough).

    In the case of wool clothing, the clothes are rubbing against your skin continuously which also causes a charge buildup. So generally you can build up charge by rubbing items together.

    Also take a look at the wikipedia entry:
  4. Aug 31, 2008 #3
    Ok thanks for that!!....but there is something else i cant understand...how and why my mother gets Electrically charged???.....i mean...sometimes she touches something metalic and she gets shocked...and some other times she "shocks" somebody else...why is that??
  5. Sep 1, 2008 #4
    I already explained it. People get charged often by rubbing against things (clothes being the most common, but a carpet rug is also a likely suspect). Usually, when you are not charged ('neutral'), the positive and negative charges that make up the atoms in your body will balance each other more or less. When you get charged (either positive or negative), it means this balanced is disturbed: you have either more negative charges (electrons) than positive charges (negatively charged) or more positive charges (lack of electrons) than negative charges (positively charged).

    When you are charged (let's say you have an excess of electrons, so you are negatively charged) and you touch a conducting object (like metal), the charge difference between you and the object will cause the excess of electrons on your skin to jump to the object. The electrons do this because they repel each other (like charges repel, while opposite charges attract) so it is 'more comfortable' for them to go to the metal object instead of staying on you. This flow of electrons is what you see / hear / feel as the spark, it is actually a current running from your body to the object.

    A small detail perhaps is that not all of the excess electrons on your body jump to the object. The electrons will keep flowing, until the object has the same charge as you. When that happens, what we call an 'equilibrium' appears. It is the most 'comfortable' for all the electrons in both objects to be in this state.
  6. Sep 1, 2008 #5
    But when she shocks somebody else shouldn't she be shocked too?
    I think flow of charges (current) passing also through her just like through her victim.
  7. Sep 1, 2008 #6
    I think that depends on whether she is grounded or not. If she is not grounded, no current can flow through her body and I don't think she would feel anything.

    My own experience (it seems to happen a lot on a trampoline) is usually that if I shock someone, I feel it too.
  8. Aug 22, 2010 #7
    Hi, I wanted to know that if it is possible to be electrically charged or zapped by, let's say one part of the human body to the entire body? This is in relation to a situation where, while sleeping, the right hand splayed out on the bed, moved unconsciously on to the upper torso. This is a part of the general physical movements a body undergoes while in R.E.M sleep. The result, however was an electric shock generated to the entire body on the hand making a physical contact, and in turn waking up the individual. There were no noticeable side effects. There were also no appliances near the vicinity of the bed, and kept in the switched "on" state.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook