Reason behind electric current

[A_curious_Homosapien]

Hello everyone, this is my first post on the website so if I make any mistakes please be patient and guide me through.

 

I'm in 10th grade and I read about electricity in my science class. In that we were told, flow of electrons produces electric current, after a few days I thought about it and developed some doubts:

1- What happens on movement of electron that electric current is produced? What is the magic magic behind the scene?

2- and if there is no logical reason, if it just happens and I take this as just a fact, like if A happens then B happens. If electrons flow, then electric current flows; won't this violet the law of conservation of energy. I mean electrons are moving so they are using some energy, but while using that energy they are also producing electrical energy. Is energy is being produced out of nowhere?

 

Again, if you find me too dumb please don't be angry. I'm just a teenager and it's pretty normal for a boy of my age to act dumb.

Thank you

[exchemist]

1 hour ago, A_curious_Homosapien said:

Hello everyone, this is my first post on the website so if I make any mistakes please be patient and guide me through.

 

I'm in 10th grade and I read about electricity in my science class. In that we were told, flow of electrons produces electric current, after a few days I thought about it and developed some doubts:

1- What happens on movement of electron that electric current is produced? What is the magic magic behind the scene?

2- and if there is no logical reason, if it just happens and I take this as just a fact, like if A happens then B happens. If electrons flow, then electric current flows; won't this violet the law of conservation of energy. I mean electrons are moving so they are using some energy, but while using that energy they are also producing electrical energy. Is energy is being produced out of nowhere?

 

Again, if you find me too dumb please don't be angry. I'm just a teenager and it's pretty normal for a boy of my age to act dumb.

Thank you

Electrons flow in response to a voltage gradient. They do not produce energy when they flow, but transmit it from whatever is responsible for the voltage gradient. So there is no violation of conservation of energy.

[swansont]

1 hour ago, A_curious_Homosapien said:

Hello everyone, this is my first post on the website so if I make any mistakes please be patient and guide me through.

 

I'm in 10th grade and I read about electricity in my science class. In that we were told, flow of electrons produces electric current, after a few days I thought about it and developed some doubts:

1- What happens on movement of electron that electric current is produced? What is the magic magic behind the scene?

2- and if there is no logical reason, if it just happens and I take this as just a fact, like if A happens then B happens. If electrons flow, then electric current flows; won't this violet the law of conservation of energy. I mean electrons are moving so they are using some energy, but while using that energy they are also producing electrical energy. Is energy is being produced out of nowhere?

 

Again, if you find me too dumb please don't be angry. I'm just a teenager and it's pretty normal for a boy of my age to act dumb.

Thank you

1. It’s not magic. We notice that charges can attract or repel, and take advantage of that to move charges around. One description is as exchemist notes - a voltage gradient; stored energy being given to the charges. You could also look at in terms of forces, if you investigated at the microscopic level.

2. An energy input is required to get the current to flow, so there is no violation.

Electrons flowing is current (in some cases, it could be protons); they are not distinct.

[zapatos]

Perhaps think of electricity like flowing water.

In a wire the current is the electrons moving in a given direction. In a river the current is the water moving in a given direction.

In a wire the battery or other power source provides the energy to move the electrons in a circuit. In a river, gravity provides the energy to move the water through its channel.

[A_curious_Homosapien]

11 hours ago, swansont said:

1. It’s not magic. We notice that charges can attract or repel, and take advantage of that to move charges around. One description is as exchemist notes - a voltage gradient; stored energy being given to the charges. You could also look at in terms of forces, if you investigated at the microscopic level.

2. An energy input is required to get the current to flow, so there is no violation.

Electrons flowing is current (in some cases, it could be protons); they are not distinct.

You said that that flow of electron is current and in some cases it can be protons too. So basically flow of charges (weather positive or negative) can produce electric current.

So if I move a charge (it can be a positively/negatively charged atom or it has to be only electron/proton?) around a solenoid it will cause change in the magnetic field around it; causing electric current to flow in solenoid (I know the current would be very weak). Right? 

[swansont]

4 hours ago, A_curious_Homosapien said:

You said that that flow of electron is current and in some cases it can be protons too. So basically flow of charges (weather positive or negative) can produce electric current.

Yes.

4 hours ago, A_curious_Homosapien said:

So if I move a charge (it can be a positively/negatively charged atom or it has to be only electron/proton?) around a solenoid it will cause change in the magnetic field around it; causing electric current to flow in solenoid (I know the current would be very weak). Right? 

Moving a charge will create a magnetic field, and yes, a change in the field will cause current to flow (or induce a voltage if there isn't a complete loop for current to flow) 

[studiot]

17 hours ago, A_curious_Homosapien said:

Hello everyone, this is my first post on the website so if I make any mistakes please be patient and guide me through.

 

I'm in 10th grade and I read about electricity in my science class. In that we were told, flow of electrons produces electric current, after a few days I thought about it and developed some doubts:

1- What happens on movement of electron that electric current is produced? What is the magic magic behind the scene?

2- and if there is no logical reason, if it just happens and I take this as just a fact, like if A happens then B happens. If electrons flow, then electric current flows; won't this violet the law of conservation of energy. I mean electrons are moving so they are using some energy, but while using that energy they are also producing electrical energy. Is energy is being produced out of nowhere?

 

Again, if you find me too dumb please don't be angry. I'm just a teenager and it's pretty normal for a boy of my age to act dumb.

Thank you

Good morning ans welcome, 10th grader.

NO it is not dumb or magic to wonder about electricity.

But electricity is a huge and very important subject.
So you have to start somewhere, your teachers cannot tell it all to you at once.

Since you mention the electron let me start there.
Britannica puts is so well.

Quote

During the 1880s and '90s scientists searched cathode rays for the carrier of the electrical properties in matter. Their work culminated in the discovery by English physicist J.J. Thomson of the electron in 1897.

 

atom - Discovery of electrons | Britannica

https://www.britannica.com › science › Discovery-of-elect..

 

The carrier of electric properties in matter.

The basic electric quantity is electric charge.
As far as we know electric charge is always attached to some particle of matter or another.

Any particle of matter that has attached charge becomes a carrier of charge as it moves about.
These particles could be electrons, protons, ions and are known as charged particles.
Some are bigger than atoms (ions) some are smaller than atoms (electrons, protons).
Atoms themselves are not charged, they are electrically neutral.

Charge endows matter particles it is attached to with extra properties, that interact with matter's own mechanical properties.
It also has some additional properties of its own.
It is these properties that hold the sub atomic particles in atoms together and hold larger assemblies of atoms together as molecules.

One of the special properties of charge is that there are two types of charge.
We use the sign convention of positive for protons and negative for electrons and neutral (=no charge) for atoms.
Ions can be positive or negative.
I say sign convention because it is simply a way of distinguishing. It does not imply any special importance of one over the other.
There are many such sign conventions in Science.

 

Back to Britannica.

A great deal of electrical theory was developed between about 1850 and 1900.
As Britannica notes, the electron was not discovered until the end of that period.
And the charge carried by the electron was not confirmed until 1910.

So the electrical theory considered electricity as some sort of weightless fluid (they tried to weigh it) that could be transferred or flow from one body of matter to another.
The flow of this fluid was called 'electric current' and supposed similar to currents of material in fluids like water.
However this theory was shown to be inadequate and that there are, in fact, several types of electric current, even before the discovery of the electron.

Nowadays we distinguish

Direct Current which is made up of a flow of current carriers which could be electrons, protons or ions in solution.
Alternating Current which is actually a flow of energy, no particles actually move anywhere though they could be said to move slightly backwards and forwards.

 

Does this start to answer you questions ?

 

[A_curious_Homosapien]

7 hours ago, studiot said:

Does this start to answer you questions ?

 

Well yes it does answer my question and also gives me some new facts, Thank you for this short and informative post :-)

[studiot]

 

Just now, A_curious_Homosapien said:

Well yes it does answer my question and also gives me some new facts, Thank you for this short and informative post :-)

Glad to help, come back if you want more detail.

[A_curious_Homosapien]

9 hours ago, swansont said:

"a change in the field will cause current to flow (or induce a voltage if there isn't a complete loop for current to flow) "

This is the missing piece I was looking for, this completes my answer. Thanks a lot swansnot, studiot, zapatos and exchemist. Thanks a lot again.

[studiot]

2 hours ago, A_curious_Homosapien said:

This is the missing piece I was looking for, this completes my answer. Thanks a lot swansnot, studiot, zapatos and exchemist. Thanks a lot again.

Whilst we are on the subject here is a question for you to think about.

It is often thought that you cannot have a current without a voltage or a voltage without a current, but you can have either situation.

Can you give an example of either or both cases, you should be familiar with at least one of them.

[A_curious_Homosapien]

4 hours ago, studiot said:

Whilst we are on the subject here is a question for you to think about.

It is often thought that you cannot have a current without a voltage or a voltage without a current, but you can have either situation.

Can you give an example of either or both cases, you should be familiar with at least one of them.

Well I have heard about voltage without current but not sure how it is possible, and current without voltage shouldn't be possible.

Can you explain both situation in depth (by depth I don't mean 10 paras, that would be inconvenient for you)? or you can just tell me about an article or book itself where I can learn about it.

[studiot]

8 hours ago, A_curious_Homosapien said:

Well I have heard about voltage without current but not sure how it is possible, and current without voltage shouldn't be possible.

Can you explain both situation in depth (by depth I don't mean 10 paras, that would be inconvenient for you)? or you can just tell me about an article or book itself where I can learn about it.

Well of course an unconnected battery is a simple example of a voltage without a current.

That was the easy one.

So a current is a coordinated movement of charge.

That can occur if the charge carriers are moved by something that affects their other material properties (remember I said they were all material ?).
Since they all have mass, some force that can move their mass and they wil take their charge with them.

For instance a thermal current, or a photocurrent in suitable electronic devices can be observed to flow when there is no voltage supply connected.

A particularly interesting example employs Newton's Laws of dynamics to light up the screens of old fashioned cathode ray tubes.
Here the electrons are initially accelerated by a voltage, but then they pass beyond the electric field and move under Newton's First Law until they hit the phosphor to make it glow.

[A_curious_Homosapien]

20 hours ago, studiot said:

A particularly interesting example employs Newton's Laws of dynamics to light up the screens of old fashioned cathode ray tubes.
Here the electrons are initially accelerated by a voltage, but then they pass beyond the electric field and move under Newton's First Law until they hit the phosphor to make it glow.

How come newton's laws of dynamics apply on sub-atomic scale?

[studiot]

3 hours ago, A_curious_Homosapien said:

How come newton's laws of dynamics apply on sub-atomic scale?

It is a question of speed.

The electrons in an ordinary vacuum tube are not moving fast enough to warrant more advanced mechanics such as relativistic dynamics.

Sub atomic particles in particle accelerators, and natural particles cosmic rays in nature achieve speeds such that relativistic calculations need to be employed.

 

For most normal interactions the electrons 'orbiting' the nucleus in atoms are not moving fast enough for relativistic calculations to be needed.
So the Schrodinger theory of wave mechanics uses classical (newtonian) evaluations of the dynamics. There is a more advanced theory making relativistic corrections due to Dirac.