Static Electricity: Why We Get Shocks on Carpet & Door Knobs

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Discussion Overview

The discussion revolves around the phenomenon of static electricity, specifically why individuals experience electric shocks after walking on carpet and then touching metal objects like door knobs. Participants explore the implications of the triboelectric series and the movement of electrons in this context.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that rubbing feet on the carpet results in a negative charge on the human body, leading to electric shocks when touching a door knob due to electron transfer.
  • Others question this assertion, referencing the triboelectric series, which suggests that the human body should have a positive charge, not a negative one.
  • One participant clarifies that insulating materials, such as socks, influence the movement of electrons, causing the body to accumulate charge when electrons are unable to return to the carpet.
  • Another participant notes that the direction of electron movement is not the only factor, emphasizing that different regions can develop varying charges even when identical materials are rubbed together.
  • Some participants discuss the relative ease of moving electrons compared to protons, highlighting the mass and inertia differences between these particles.
  • There is a reiteration that the movement of electrons does not definitively resolve the question of their direction during the charging process.
  • One participant mentions that the electronegativity of materials can affect the direction of electron movement, adding another layer of complexity to the discussion.

Areas of Agreement / Disagreement

Participants express differing views on whether the human body gains a negative or positive charge when interacting with carpet. There is no consensus on the direction of electron movement or the implications of the triboelectric series, indicating that multiple competing views remain.

Contextual Notes

The discussion highlights limitations in understanding the nuances of charge transfer and the factors influencing electron movement, such as material properties and environmental conditions. There are unresolved questions regarding the assumptions underlying the triboelectric series and its applicability in this context.

Who May Find This Useful

This discussion may be of interest to those studying static electricity, materials science, or anyone curious about the principles of charge transfer and the triboelectric effect.

Biker
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Here is the rub. Most of the online sources and in a kind of statement in my book says that we gain a negative charge when we rub our feet on the carpet. So when we touch a door knob we get a electric shock because the electrons is transferred from us to the door knob

However, Shouldn't it be the opposite? In the triboelectric series, Human body is on the top of the list.. So it is supposed to have a positive charge not a negative one.

Here is the series if you want it : http://soft-matter.seas.harvard.edu/images/8/8e/Tribo.png
 
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Biker said:
Here is the rub. Most of the online sources and in a kind of statement in my book says that we gain a negative charge when we rub our feet on the carpet. So when we touch a door knob we get a electric shock because the electrons is transferred from us to the door knob

However, Shouldn't it be the opposite? In the triboelectric series, Human body is on the top of the list.. So it is supposed to have a positive charge not a negative one.

Here is the series if you want it : http://soft-matter.seas.harvard.edu/images/8/8e/Tribo.png

The positive charge is the proton. The negative charge is the electron. The proton has more mass than the electron, so has a higher inertia (resistance to movement). So it is easier to move an electron (negatively charged) than a proton (positively charged).
 
Kyx said:
The positive charge is the proton. The negative charge is the electron. The proton has more mass than the electron, so has a higher inertia (resistance to movement). So it is easier to move an electron (negatively charged) than a proton (positively charged).
I haven't said anything about moving a proton... I said that the electrons moves from us to the carpet not the opposite. So we will be left with a positive charge.
 
Biker said:
I haven't said anything about moving a proton... I said that the electrons moves from us to the carpet not the opposite. So we will be left with a positive charge.

Insulating materials are more likely to lose or gain electrons, so the socks that you wear are gaining/losing the electrons. By taking your foot off the floor, you are causing the electrons to no longer be able to get back to the carpet, so you are 'spreading' the charge around your body. Then when you touch the door knob, the electrons 'jump'.
 
Biker said:
However, Shouldn't it be the opposite? In the triboelectric series, Human body is on the top of the list.. So it is supposed to have a positive charge not a negative one.
Usually you're rubbing your shoes against the carpet, not your skin. (But interesting question.)
 
Biker said:
So when we touch a door knob we get a electric shock because the electrons is transferred from us to the door knob
The direction doesn't really matter, but if you wear shoes or socks, see Doc Al.
In addition, this triboelectric series is an oversimplification, you often get different regions of different charge, even if you rub two identical materials against each other.

Kyx said:
The positive charge is the proton. The negative charge is the electron. The proton has more mass than the electron, so has a higher inertia (resistance to movement). So it is easier to move an electron (negatively charged) than a proton (positively charged).
It is clear that electrons move, but that doesn't answer the question in which direction the electrons move.
 
Kyx said:
The positive charge is the proton. The negative charge is the electron. The proton has more mass than the electron, so has a higher inertia (resistance to movement). So it is easier to move an electron (negatively charged) than a proton (positively charged).
mfb said:
It is clear that electrons move, but that doesn't answer the question in which direction the electrons move.
Nor is it an accurate description of why it is easier to get the electrons to go between materials. The outer electrons are much more loosely bound to the material than the inner electrons and nucleus. Which direction the electrons go depend on things such as the electronegativity of the materials.
 

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