Why electrons are negatively charged

This causes the chemicals on the battery plates to store energy, like winding up the spring in our spring-powered water pump. See how "charging" and "charges" can create a horrible mess of misunderstandings? When this mess gets into the textbooks and educators start teaching it to kids, the kids end up believing that Electricity is too complicated for them to understand.

Yet the fault does not lie with the students!!!! Another one: if you "charge" a capacitor, you move charges from one plate to the other, and the number of charges within the device as a whole does not change. But capacitors have exactly the same total charge within them whether they are "charged" or not!

Whenever we take an electron from one plate, we put an electron onto the other plate. When we speak of "charging" capacitors, we've suddenly stopped talking about charge, and started talking about electrical energy. This basic concept is very important in understanding simple circuitry, yet it is rarely taught. The misleading term "charge" stands in the way of understanding. I suspect that students are not the only ones being misled. Many teachers misunderstand simple physics, and they believe that the purpose of a capacitor is to store electric charge.

Yet electric charge is the medium of energy storage in both coils and capacitors. In capacitors, energy is stored in the form of "stretched charge", or potential energy, while coils store energy in the form of moving charge which contains kinetic energy.

However, we don't put any charge into a capacitor when we "charge" it , any more than we put charge into a superconductor ring-inductor when we give the ring a "charge" of electromagnetic energy. It appears when two dissimilar insulating materials are placed into intimate contact and then separated.

All that's required is the touching. For example, when adhesive tape is placed on an insulating surface and then peeled off, both the tape and the surface will become electrified. No rubbing was required. Or when a plastic wheel rolls across a rubber surface, both the surface and the wheel become electrified.

Intimate contact is sufficient, and no rubbing is needed. Of course if one of the materials is rough or fibrous, it does not give a very large footprint of contact area.

In this case the process of rubbing one material upon another can greatly increase the total contact area. And the heating of the fibers can make the materials even more electrically "dissimilar", which aids the charge-separation process. But this rubbing is not the cause of the electrification. During contact-electrification it is usually only the negative electrons which are moved. As negative particles are pulled away from the positive particles, equal and opposite areas of imbalance are created.

In one place you'll have more protons than electrons, and this spot will. Elsewhere you'll have more electrons than protons, for an overall negative charge. You've not caused a "buildup", you've caused an imbalance, an un-cancelling, a separation. The law of Conservation of Electric Charge requires that every time you create a region of negative charge, you must also create a region of positive charge. In other words you must create a separation of opposite charges.

If you want to call it a "buildup of electrons", then you also need to call it a "buildup of protons," since you can't have one without the other. It doesn't matter whether the region of imbalance is flowing or whether it is still.

Only the imbalance is important, not the " staticness. All solid objects contain vast quantities of positive and negative particles whether the objects are electrified or not. When these quantities are not exactly equal and there is a tiny bit more positive than negative or vice versa , we say that the object is "electrified" or "charged," and that "static electricity" exists. When the quantities are equal, we say the object is "neutral" or "uncharged.

Since "static electricity" is actually an imbalance in the quantities of positive and negative, it is wrong to believe that the phenomenon has anything to do with lack of motion,. When this happens, it continues to display all it's expected characteristics as it flows, so it does not stop being "static electricity" while it moves along very non-statically!

In a high voltage electric circuit, the wires can attract lint, raise hair, etc. A disconnected wire contains charges which are not moving they are static, yet it contains no "static electricity! To sort out this craziness, simply remember that "static electricity" is not a quantity of unmoving charged particles, and "static electricity" has nothing to do with unmoving- ness. If you believe that "static" and "current" are opposite types of "electricity," you will forever be hopelessly confused about electricity in general.

Electric power cannot be made to flow. Power is defined as "flow of energy. It's as silly as saying that the stuff in a moving river is named "current" rather than named "water.

Talking of "current" which "flows" confuses everyone. The issue with energy is similar. Electrical energy is real, it is sort of like a stuff , and it can flow along. When electric energy flows, the flow is called "electric power. Electric power is the flow rate of another thing; electric power is an energy current. Energy flows, but power never does, just as water flows but "water current" never does.

The above issue affects the concepts behind the units of electrical measurement. Energy can be measured in Joules or Ergs. The rate of flow of energy is called Joules per second. This makes for convenient calculations. Yet Watts have no physical, substance-like existence. The Joule is the fundamental unit, and the Watt is a unit of convenience which means "joule per second. I believe that it is a good idea to teach only the term "Joule" in early grades, to entirely avoid the "watt" concept.

Call power by the proper name "joules per second". Only introduce "watts" years later, when the students feel a need for a convenient way to state the "joules per second" concept.

Unfortunately many textbooks do the reverse, they keep the seemingly-complex "Joule" away from the kids, while spreading the "watt" concept far and wide! Later they try to explain that joules are simply watt-seconds!

If you aren't quite sure that you understand watt-seconds, stop thinking backwards and think like this: Joules are real, a flow of Joules is measured in Joules per second, and " Watts " should not interfere with these basic ideas. They only travel at , miles per second while in a perfect vacuum.

Light waves travel a bit slower in the air, and they travel LOTS slower when inside glass. The term "speed of light" is misleading, because the complete term actually reads "speed of light in a vacuum.

Sustaining a magnetic field requires no energy. Coils only require energy to initially create a magnetic field. They also require energy to defeat electrical friction resistance ; to keep the charges from slowing down as they flow in wires. But if the resistance is removed, the magnetic field can exist continuously without any energy input. If electrically frictionless superconductive wire is used, a coil can be momentarily connected to an energy supply to create the field.

Afterwards the power supply can be removed and both the current and the magnetic field will continue forever without further energy input. During a Direct Current in a simple circuit, the flow of charges takes place throughout the whole wire. The flow is not just on the surface. If the level of current is very high, then the wire will become hot, and the current will heat up the inside of the wire as well as its surface.

Thin hollow pipes make poor conductors; their electrical resistance is too high. To avoid overheating the metal we should use thick solid bars instead. There is a persistent 'rumor 1 that electric current exists only on the surface of metals. This mistaken idea probably comes about through a misunderstanding of the nature of electric charge.

After all, when electric charge is deposited onto a metal object, it distributes itself over the surface of the object. It makes sense that, since charge is only on the surface of metals, a flow of charge must take place only on the surface of metals, right?

Unfortunately, the word "charge" refers to two different things. When electric charge is placed on a metal object, the added charge is just a drop in the bucket compared to the amount of charge already in the neutral metal. Are you confused yet? All metals contain huge amounts of movable electrons. During an electric current it is these electrons which flow. However, each electron is near a proton, and so the metal is said to be "uncharged.

Weird but true. The "water level" would rise a tiny bit. Yet extra charges on a wire create a very noticeable electrical imbalance they attract lint, deflect electroscopes, make sparks, etc. It isn't so strange that we might accidentally assume that the extra charges are the only charges on the wire.

Yet in reality, electric currents happen in the "ocean" of the wire, and the extra "teacup" on the surface has little effect on the charge flow. The charge flow current is not just on the surface, and the whole "ocean" flows. A second source of misunderstandings: during high frequency AC, the electric current on the surface of a conductor is higher at the surface. This is called the "skin effect. Perhaps some people heard about the Skin Effect but did not realize that it only works for very thick wires or for high frequency AC.

At extremely high frequencies, the current does flow as a "skin" on the surface of large wires. For circuits involving high-current and high-frequency such as radio transmitters, it makes sense to use copper pipes as conductors. All the charge flow is on the surface of the conductors. All the heating takes place on the surface, and not deep within the metal. Electric charges are very visible, even though their motion is not. When you look at a metal wire, you can see the charges of electricity which flow during electric currents.

During an electric current, it is the "silvery" stuff that flows along, under construction. Students misunderstand how electric circuits work. One reason for this is that they think the electrons in a metal are trapped on individual metal atoms.

They also think that an applied voltage is needed to "free" the electrons and to change metal into a conductor. They aren't aware that the "sea of electrons" exists inside metal all the time. I suspect that this is part of a more general misconception that all atoms in a material are always neutral. The very definition of "conductor" is "a material which contains mobile charges.

If all atoms were truely neutral, then conductors could not exist. For example, a metal is made of positively charged atoms immersed in a sea of loose electrons. Apply a voltage to a metal, and its electrons begin flowing. Salt water is full of positive and negative ions.

Glowing gas fluorescent lights, neon signs, sparks is full of movable electrons and movable positive ions. These three are the most common conductors, and they owe their conductivity to the presence of movable charged particles which occur naturally. The scientist's definition of the word "conductor" is different than the one above, and the one above has problems.

For example, a vacuum offers no barrier to flows of electric charges, yet vacuum is an insulator. Also, there is a similar problem with air: electric charges placed into the air can easily move along, yet air is an insulator. Or look at salt water versus oil. Oil is an insulator, while salt water is a conductor, yet neither liquid is able to halt the flow of any charges which are placed into it. How can we straighten out this paradox? Easy: use the proper definition of the word "conductor.

Conductor - a material which allows charges to pass through itself. Conductor - a material which can support an electric current. Conductor - a material which contains movable electric charges. Conductor - like a pipe which is already full of water Insulator - like a pipe with frozen liquid; a pipe plugged by ice If we place a Potential.

Difference across either air or a vacuum, no electric current appears. This is sensible, since there are few movable charges in air or vacuum, so there can be no electric current. If we place a voltage across a piece of metal or across a puddle of salt water, an electric current will appear, since these substances are always full of movable charges, and therefore the "voltage pressure" causes the charges to flow. In metal, the outer electrons of the atoms are not bound upon individual atoms but instead can move through the material, and a voltage can drive these "liquid" electrons along.

In salt water, the individual sodium ions and chloride ions are free to flow, and a voltage can push them so they flow as an electric current. If we stick our wires into oil, there will be no electric current, since oil does not contain movable charges.

This is how CRT's and vacuum tubes work; electrons are forcibly injected into the empty space by a hot filament. However, think about it for a second: it's no longer a vacuum when it contains a cloud of electrons! But vacuum tubes already have another name, so this would just confuse things.

They are called "hollow-state devices. Electrostatic experiments don't work very well under humid conditions. Some books state that the water vapor in the air makes the air conductive. In reality the problem is caused by the liquid water adsorbed on surfaces. In order to make the air conductive, we'd have to fill it with movable charged particles. Evaporated water is not made of charged particles ions, it's made of neutral molecules, so the high humidity does not significantly affect the conductivity of the air.

Even suspended water droplets fog does not significantly affect humidity. For fog to be conductive, the individual droplets would have to be electrically charged. However, during humid conditions most insulators develop a surface layer of conductive liquid made of water mixed with contaminants including dissolved salts which makes this layer of water conductive.

If you find that you can't separate any charges by rubbing a balloon on your head, it's because the humid air has made the balloon and the hair very slightly damp. The air remains nonconductive, but surfaces of insulators become conductive when damp. Conductive surfaces don't separate any opposite charges when rubbed together. Cure this by warming them drying them with a blow-dryer. If a pair of insulators is sufficiently dry, it will "generate charge" even under humid conditions.

If conductive air was the culprit, this couldn't work. If by 'electricity 1 we mean the electrons, then 'electricity' is not weightless. Take a copper wire for example. References Dehmelt, H. Weise, W. Quarks and Nuclei: World Scientific. How to Cite. Saleh, G. Vol 6 No 1 : Regular Issue. The right to make copies of the Work for internal distribution within the institution which employs the author.

The right to use figures and tables of the Work, and up to words of text, for any purpose. The right to make oral presentations of material from the Work. Publishing rights without restrictions. The objects in a material that are contributing the most to an electric current are called the charge carriers.

Third, electric charge carriers aren't always electrons and they aren't always negative. In fact, in the natural world, the charge carriers are usually not just electrons. In animals, the electric charge carriers are primarily sodium, potassium, calcium, and magnesium ions, all positively charged.

They are the things that are moving when a nerve passes an electric signal. In the ionosphere, the charge carriers are oxygen, hydrogen, and helium ions along with electrons. In a gas discharge sign, the electrical current is due to ions and electrons.

A relevant cartoon: xkcd. Add a comment. Active Oldest Votes. Charge is only the measure of interaction. Let's see this on the simple example. Improve this answer. It seems that we don't have the "gravity-is-the-bending-of-space-time" explanation for charge yet. We can describe the What but not the Why. Great overall question! WHY questions in physics on fundamental definitions end up on the postulates and laws which have to be assumed so that a mathematical model fits existing data and predicts new observations.

One of the implicit postulates from data is the existence of two opposite charges. Danijel Danijel 2, 1 1 gold badge 13 13 silver badges 21 21 bronze badges. SchrodingersCat 4, 3 3 gold badges 19 19 silver badges 45 45 bronze badges.

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