Beginner physic q: Electrostatic, plastic and paper pieces. Who loses electrons? - Page 1
Forum section: electronics / beginners

author: Sibb
author_rank: Newbie
timestamp: November 17, 2020, 08:15:31 am
content: I try to learn the basics, and if I don't understand something, I forget it quickly. That is why I am here. Could you spare your time and help me?We rub wool and plastic.When we do this, do we add energy to the wool? Do we convert mechanical energy into something?Atoms of wool lose electrons. Why? I know that the outa electrons have much weaker bond then inner electrons.The atoms of plastic get extra electrons, plastic becomes negative.Why does negative plastic attract neutrally charged paper?+ and - attract each other+ and 0 attract each other as well? What about - and 0?In case of silk and glass, glass loses electrons and becomes positive. What determines who loses electrons?The bond between the electrons and the nucleus is stronger when the distance between them is the smallest (first layer).Perhaps... the plastic atom has fewer layers than wool. The last electron layer of the plastic is stronger than the last bound layer of wool.The mentioned "elements/objects" are isolators. Through rubbing conductors happens the same but no electrostatic is build up, because the electrons can "move" away.My questions:Through rubbing: What energy do we convert? Mechanical is converted to heat and heat removes electrons?Why does negative plastic attract neutrally charged paper?What determines who loses electrons?

author: pwlps
author_rank: Frequent Contributor
timestamp: November 17, 2020, 10:59:36 am
content: Quote from: Sibb on November 17, 2020, 08:15:31 amhttps://en.wikipedia.org/wiki/Static_electricityJust looked at it and it seems all three questions are discussed.Edit: as for the paper I don't know if it is purely dipolar or because it is slightly conductive.

author: ledtester
author_rank: Super Contributor
timestamp: November 19, 2020, 08:54:36 am
content: QuoteLook up the "triboelectric effect" and the "triboelectric series" for a discussion of the mechanism:https://en.wikipedia.org/wiki/Triboelectric_effect#Triboelectric_series

author: Sibb
author_rank: Newbie
timestamp: November 19, 2020, 11:53:10 am
content: I usually ignore wikipedia, because it has so many cross references, but both articles were nice to read.Please correct me if I am wrong:-Through rubbing, electrons jump from one to another material, because one material's nucleus has a weaker bound to his valence (outer shell) electrons. Other material has space for additional electrons in his outer shell.Glass - Silk => Glass loses electrons, get positively charged-To remove electrons we need energy, hence through rubbing we get triboelectricity, which was converted from mechanical or heat energy (I am not sure).The information I am missing is why the electrons move from glass to silk. Because of the rubbing but why? The two materials touch each other, two different atoms come together and electrons jump from one atom to another. But why?

author: pwlps
author_rank: Frequent Contributor
timestamp: November 19, 2020, 07:37:07 pm
content: Quote from: Sibb on November 19, 2020, 11:53:10 amIt depends, but I find most of wikipedia articles rather well written compared to other sources I can find on internet. And these two are excellent.QuoteIt is complex. Each material is composed of different atoms with different electronegativities. Different atom pair bonds temporarily created during the friction motion can make electrons jump one way or the other, the net effect will thus depend on the detailed surface structure of both materials and this is why it is quite difficult to predict.QuoteFor a slow moton it will be mechanical. To make "free" electrons ready to move from one side to the other you need to break bonds that are temporarily created during the motion, hence a meachanical force is needed.QuotePulling apart atoms that were bonded can create short-lived ions ready to pair with other atoms. But this is a complex process, I don't know it in details.

author: TimFox
author_rank: Super Contributor
timestamp: November 19, 2020, 07:52:39 pm
content: In chemistry, some atoms lose electrons easily (loosely bound to the nucleus and inner electron shells), while other atoms easily capture electrons. The physics behind this is very interesting, but should be studied carefully. For example, sodium (Na) in solution loses an electron to become the positive ion Na+, while chlorine (Cl) gains an electron to become the negative ion Cl-. The Na atom has one electron outside of completed shells, while Cl (at the other side of the Periodic Table) is one electron short of a complete shell. Explaining the Periodic Table was an important early success of Quantum Mechanics.

author: ejeffrey
author_rank: Super Contributor
timestamp: November 19, 2020, 11:20:01 pm
content: It's not so much rubbing as touching. Rubbing is just a way to generate lots of contact points. The transfer of electronics itself doesn't require energy,When two materials are in contact, their electrons start to overlap. In fact, this is what "contact" means. If one material has a greater affinity for electrons than the other. it will grab some and become negatively charged. The other material with less electron affinity becomes positively charged. This process doesn't require energy, it actually releases a bit of energy. However, when you pull the surfaces apart, you are separating a positively charged object from a negative one. That part does cost energy, but the transferred electrons are now too far away to hop back.If you generate a large static charge and then use it to create a spark, the energy released actually came from this step where you pull the charged objects away from each other.

author: Sibb
author_rank: Newbie
timestamp: November 20, 2020, 04:04:41 pm
content: Quote from: ejeffrey on November 19, 2020, 11:20:01 pmSeems like you are wrong, found multiple sources:Electrons in an atom are held there by the force of attraction exerted by the positive charge of the nucleus on the negative charge of the electron. Energy is required to remove an electron from atom to overcome this attractive force.Thank you guys.

author: ledtester
author_rank: Super Contributor
timestamp: November 20, 2020, 07:10:08 pm
content: Quote from: Sibb on November 20, 2020, 04:04:41 pmBe careful of saying that somebody is "wrong" on an Internet forum. Usually this happens because you're not talking about the same situation. Instead, ask something like "how do you reconcile that with what this web site says here (and provide the link)". That is much more helpful at getting to the what the right answer/explanation is.Yes - it takes energy to fully remove an electron from an atom, but the electron is going back into another atom which releases energy. The net difference is usually negative which is simply reflective of the propensity for the transfer to happen.Have a look at the figures on this page:https://www.keyence.com/ss/products/static/resource/feature/Stronger bonds are states of lower potential energy. In step 2 a electron from the right atom finds a lower energy state in the left atom resulting in the release of the difference in the energies.How does this compare with the other sources you've come across?