Physical Science 6.8a - Electric Current and Magnetic Fields

From the Physical Science course by Derek Owens. An introduction to the magnetic fields caused by current flow through a wire. Distance learning classes are available at www.derekowens.com

[@sad1k1e]

Bravo Bravo!!!. It took years to really understand this, you made it so easy. there's a saying "there are no bad students, only bad teachers" you proved it man.

[@jarober9781]

It was very helpful for my. Finally I get it! Thank you

[@tioa.p.1058]

I AGREE WITH YOU BROO

[@sander_bouwhuis]

Good and clear explanation. Thank you!

[@omrdso]

Simply Wonderfull explaination

[@Penndennis]

Great job Mr. Owens. Many thanks.

[@Mark1Mach2]

Watching in 2019, still find it a very nice explanation!

[@krutarthmehta5496]

After studied four years of hardcore engineering in electronics and communication. I always stuck why a piece of iron or something put middle of the inductor.I couldn't understand in my engineering days.thank you Derek...........

[@sez10]

Thank you so much!! video was so helpful. I really appreciate wonderful videos like yours

[@randomlettersqzkebkw]

extremely clear +1 subscribed diagrams make things a LOT easier to understand Could i ask you what software are you using for those drawings?

[@DiegoCarvacho]

very well done! easy to follow. thanks a lot

[@TheDaniyal1996]

I have an exam tomorrow, you saved my life. Brilliant explanation bro

[@pushpavel.jjanakiraman8146]

Your Tutorials are Awesome!

[@SalsaKingoftheApes]

Excellent explanation

[@upulrathne6653]

thank you

[@Adaeze611]

I love the font!....on and the lesson is great. Thanks!

[@SwissExperiments]

Thank you, this was very well explained, however there is a huge mistake that you should note: The voltage has nothing to do with the coil heating up, it's all about the current. The current flows, the voltage applies. You could melt a coil using 1V and 1000A, however putting 1000V on a wire is pretty common and wouldn't damage the coil unless not insulated.

[@derekowens]

Right, although I believe I would say that it is about *both* the voltage and the current. Heat is energy, and Power is energy over time. The Power is current times voltage. The current and the voltage both contribute to the heat, and they do so equally.

[@SwissExperiments]

Derek Owens I could agree with you, however, if you look at the power as in P = V^2/R or P = I^2*R, given R = 2, if you increase V, you get a certain power, however if you increase I, you get more power. And if you increase the R, you'll see that as R tends to infinity, given any V, P will be equal to 0, whilst, given any I, P will be infinity. But yeah, too many factors should be considered, like the real Resistance of the wire, the power supply, the internal resistance and so on. Theoretically if the wire is a 0 ohm wire, then the currently flowing would be infinity and the power too. Let's just say we're both right ;)

[@derekowens]

Swiss Experiments - Castagnola007 Sounds good! One other thing, though. Even though P = I²R, you can not increase R with constant I. There is a cause and effect that takes place. Increasing R will *cause* a decrease in I. In order to increase R and keep a constant I, you would have to also increase V.

[@SwissExperiments]

That's right ;)

[@forcedtocreate]

Thanks for the response and I do prologize for the seemingly frustrated tone. There are things that just erk me about our educational systems. Like how half our science text books are filled with unnecessary information. Get to the meat I say. :)

[@yourmumsalternatingjeff5630]

brilliant video, was wondering can electromagnets only be DC since if it were ac poles would keep flipping? also, hypothetically, if we were to use DC in the form of a very large dry cell and a superconductor for the coil, would the electromagnet be hindered by the internal resistance of the DC battery?

[@derekowens]

Yes, I believe that is correct. You would not make an electromagnet with alternating current. And yes, a battery's internal resistance would limit the current flow, which would affect the magnetic.

[@Cycl_ps]

When he talks about using superconductors, does he mean as the wire or the core. I would imagine it would be the core, but I don't understand how the core would heat up at high voltages. Any help would be appreciated.

[@derekowens]

I hear you. By convention I assume you mean conventional current flow. Probably the most consistently confusing issue to physics students, for the past two centuries. I try to explain both, by the way, so my students will understand the source of the confusion.

[@gbpce7766]

hi derek... its awesome..from where u hv lernt all this things. rigt nw i m very clr wid this. thank you. please upload some more videos...

[@StanJan]

Please help me understand. What proves that the field actually "flows" in the direction we are stating here. Right hand rule.. Clockwise following the direction of the current. And for that matter, how do we determine there is actually a "flow" of current ? Very hard to go to step two, when i cant understand how the initial assumptions are arrived at. Did i ask that clearly enough ? Stan

[@RolndoGalidoGuerzo]

What if we use copper tubings as solenoid and pump water through the solenoid tubes, will the water current traveling along the solenoid also produce a magnetic field? Thanks!

[@alunmactavish]

is there an equation in which the resistance or number of coils will give the best magnetism in relation to the votage used ?

[@marcm2533]

God bless your soul

[@janderro]

very nice vid! what software did u use?

[@thomascampbell6406]

hay just a question here ? The magnetic field is constant then when one electron current goes to start to finish right ??

[@antony172]

hey thx it so much helping me understand the horrible concept..........

[@RSPSpro1]

what program are you using to do this?

[@FingerThatO]

THANK YOU THANK YOU!

[@happy543210]

the wire cant be bare copper. it must be insulated (with enamel) or the charge will short across the coil rather than through it.

[@moonwalker491]

How would one contain plasma in a magnetic field?

[@TanmayMukim_dhab]

Plasma is nothing but the Electrons+Ions & as we know the eletrons can be grabed & placed where you want (normally in potential well it is placed) using high magnetic field. While working with plasma there is one concept of magnetron target (Search-Plasma Sputtering systems or Magnetron target), Where high magnitude magnetic field lines acts as a double convex lens. This Double convex lens grabs or focuses the electrons/ions of Plasma just like a ray of light.

[@rileymitchell254]

I'm trying to do a science fair project on electricity. And I have no clue how i am going to do it. And i only have two weeks. Can you explain it to me in a easier way!

[@McGavel1]

What is the point you want to convey about electricity in the project?

[@rileymitchell254]

I'm trying to make a electro magnect. And i need help understanding how the wire works.

[@hemalatha2174]

thank u

[@jaimedpcaus1]

What are the materials that make super conductors?

[@TanmayMukim_dhab]

Graphene is used

[@jaimedpcaus1]

+Tanmay Mukim Hi, is that the newly found Carbon based 1 atom think material? Is it the one they discovered by mistake using regular tape (hence, thickness)?

[@TanmayMukim_dhab]

Jaime Perez Yes, there are other materials like tooniobium-titanium, germanium-niobium too. But scientists just found out the superconductivity of graphene. The thickness controlled growth is known as "Thin Film Formation" too. May be you have heard about MEMS accelerometers because of which your mobile detects the rotation of the screen. www.sciencealert.com/wonder-material-graphene-has-been-turned-into-a-superconductor

[@jaimedpcaus1]

+Tanmay Mukim Cool. thanks. :-)

[@dpunisha4u]

mr derek knows how to draw what he's thinking asap

[@PopulistDavid05401]

Spheretext

[@ptitjo9475]

7:39

[@racholpereira1525]

I think magnetic field flows from north to south ..whereas here in this video ..the case is reverse..

[@zeroquanta6130]

This is very confusing if you don't put a battery in this picture. I know you know that the positive moves to the negative, sooo your thumb is actually pointing at the Negative side of the battery. Fist up, Fight for Truth.

[@batmandeltaforce]

Your battery is backward:)

[@ballsoffury4]

You are a beautiful man... I say that in the most heterosexual way possible :)

[@NinjaOnANinja]

4:22 Alright, so you brought up a rule. The right hand rule or w/e. Now you are going against your very own rule by breaking the concept. The point is to clarify, now you are taking that concept and running off with it to create some other crap? Like, what the hell dude? Reaching under? Why the fuck would you make up this concept if you are going to change the mechanics of it? Again, fuck math.

[@CosmologicaI]

He didn't change anything. You are supposed to point your thumb in the direction that the current is flowing, requiring you to flip your hand palm upwards in order to represent it that way. The right hand rule has been around for quite some time and is just a way of quickly finding the direction of the result of a cross product without doing any math.

[@NinjaOnANinja]

CosmologicaI I did misunderstand originally. I assumed the right hand rule was to tell you the direction of flow, not so much the made up fairy tale part of the "negative flow". That is why I was like WTF? But overall, my statement still stands that math is getting very stupid and this whole concept makes no sense at all. It is better to say that you place your hand and point your thumb opposite of the electrons instead of making all that other stuff up. That is far more logically sound than "I guessed and we agreed because herp derp".

[@CosmologicaI]

It sounds like your problem is actually with conventional current as opposed to the right hand rule. Conventional current is just that; conventional. As Derek stated, it's the way we've looked at it for a long time. Would it be more physically accurate to describe current as the flow of electrons? Yes. However, both models have identical predictive capability, so there is no point to prefer one or the other. If it ain't broke, don't fix it. If you don't like the right hand rule then use the left hand rule. It's really an arbitrary choice.

[@NinjaOnANinja]

CosmologicaI You're missing the point. They are "assuming" that if electrons flow one way, negative stuff, that positive flows the other. Hence they demonstrated that. The issue I am having is that they used the words "assume" or "pretend" or "for the sake of" and such. Now the problem with that is that people base future knowledge off of assumptions. You cannot pull an element out of thin air. You cannot assume something into existence. You can't use pretend as evidence. My point was so that the world would rely on evidence and not pretend. All this stuff does is fills the head of the students with useless knowledge. Which every truly great mind understands how important it is to keep your brain from such knowledge to allow easy learning of other important knowledge. Or else you become an old stubborn man. For me, I would rather deal with what I can actually "put my hands on" rather than only what can be seen once you accept someone else's rules or theories. I would also rather keep my thoughts free flowing with logical resolve and not because he said so reasoning. I see a greater picture. I simply propose that to everyone else in hopes you all see it too.

[@CosmologicaI]

NinjaOnANinja What is wrong with assuming conventional current when both models yield identical scientific results? Why do you think this knowledge is useless? There is no knowledge that prevents other knowledge from being ingested by an individual. What is wrong with "accepting someone else's rules or theories" when they have the proof to back them up? A theory is, in fact, an idea backed by a fair amount of evidence.

[@Inublue50]

12 years later and video still holds up well! As a EE student, this explanation was oh so perfect. Thank you so much.

[@microk7648]

12 years old?! that's amazing

[@MrTyrone123321]

excellent explanation

[@oscarcastanedamunoz]

Goddam, This guy is one hell of an artist.

[@taryndean8204]

Haha.

[@derekowens]

Thanks very much for the encouraging feedback! I'm very glad these videos have been helpful to you. Derek Owens

[@isfahanikamal6180]

@Derek Owens Could you tell me other applications like this. An application that we can draw while explaining it at thr same time.. thanks

[@sharbeldahlan]

Thanks a lot =) your videos are very very helpful!! better than the book, and much better than any of the physics teachers that had taught me !!!

[@derekowens]

I have a tablet (yes, it's a Bamboo) and I use some screen capture software, and I have a pretty good microphone. The hardest part was getting used to lecturing with no students in the room!

[@derekowens]

@idster7 Yes, that's right. If you think in terms of electron flow, then the left hand rule applies instead of the right hand rule. This difference is, unfortunately, somewhat confusing, has been an endless source of confusion to physics students for the past century.

[@DiegoGarcia-pd7vq]

excuse me, Why the metal nail enhences the magnetic field? I am curious to know ! thanks !

[@naveensundar4765]

same doubt for me

[@xxjacobxx3]

wonderful man. thanks a lot. what program do you use to draw this stuff, and do you use a bambo draw pad, or do you draw strait onto the monitor?

[@Benzy-OvO]

Who is not at school because of COVID-19

[@derekowens]

Yes, it does matter. If the wires are not insulated, then the electrons could jump from one loop to another, thereby moving directly from one end to the other instead of going around in loops. They need to follow the loops to generate a strong magnetic field.

[@derekowens]

The difference between the electric field and the magnetic field is 90 degrees. :) Seriously, as they are directional in nature, they are usually different by 90 degrees. Also a magnetic field is only present if there is charge in motion. An electric field is present if there is charge, period. But you are right that they are related. In fact, they are usually thought of as both being manifestations of the same theory, electromagnetism.

[@mysticalsoulqc]

wow incredible drawing gift what device do you use to draw like that? great vid..thx bro!

[@derekowens]

@BrydonBear Thanks! And yes, that's correct. Current is the flow of charge through a wire. Specifically charge is measured in Coulombs, and current tells us the amount of charge that flows past a point in a given time. One Coulomb of charge per second is 1 Ampere, or 1 Amp, or current. Current flow is usually electrons flowing, but any charged particle moving would be called electric current.

[@sth128]

Great video. I'm trying to calculate the induced current of a cylindrical magnet moving through a wire coil, but I'm too lazy to read through my old text. Can you give me (or point me in the direction) the formula?

[@frankiefrank4853]

Greatest explanation on this topic I've seen in years

[@checkingthetoob]

Very nicely done, drawings too. What's your thoughts on the magnetic field actually being magnetic particles? ?

[@Gugglewolfgaming]

Thankyou so much, I'm doing GCSE physics and my teacher, although good most of the time, didn't explain electromagnetism to us very well at all, I need to understand something to remember it so I struggled to remember all this but then I found your video and I understand how it works so I can apply this to the exam, thats the way my brain works, cant memorize well but if I understand a set of rules I can use them to work out the answer for myself in my mind. Thanks much, its more interesting than I thought too.

[@suckysucky3194]

Gugglewolf I'm 12 and doing this

[@sotirissarros3522]

Thank you! Very nice demonstration. Just out of curiosity, how do you make all these nice drawings? Is it a program that you use?

[@vincecox8376]

The "B" field is the most powerful part of a magnet! It's the center of a magnet and allows North and South to exist. It also is the force that allows the force to flow!!! No one other thing,, Tap anything with just the "B" field of a magnet and you will see it loose weight!! about .2/3rds If you move it around it will gain its weight back..

[@HumpadyDumpady]

Forgive me for my ignorance, but I'm trying to get my mind around this rule of thumb here. (+) charges need to be immobile in metal, so at 5:45 we must assume e- are the charge flowing IN at the bottom. In this case, wouldn't the magnetic field point downward inside the coil??

[@sharonsolana]

You say: Positive charge flowing one direction is mathematically equivalent to negative charge flowing the opposite direction. What equations are you using please? I understand your description of - electron flow to the right vs. conventional + flow to the left. Thank you in advance!

[@hristoborisov3713]

so weird how we know so much about electrons and magnetic forces, but we actually know next to nothing about how or why they act this way anyone knows of an experiment that simulates the earth's magnetic field by using liquid melted metal as the source of the field? edit: nvm found it myself, kzbin.info/www/bejne/qHK8iGykbc5geZY

[@crihs6108]

The proton isn't moving

[@caroljengkind2]

Hi there, I must say I liked your video lecture! Blue and yellow colors somehow do attracts me to your notes longer. And I liked the example of every applications that you gave for every principle you were trying to explain! That makes me understand better! Great job! =)

[@Layarion]

so in reality it 'should' be the "right hand rule but reverse the direction of your hand when trying to point the thumb towards the positive end"?

[@snoopydogg9465]

Nice drawing

[@rogerg4916]

The "right hand rule" is a convenient way to express the direction of current flow relative to direction of the magnetic field but what is the purely mathematical way to express it without reference to the human hand?

[@JoyOfCuriosity]

We did an experiment covering this and other electromagnetism projects here: kzbin.info/www/bejne/jWLLe2VnbJKalac

[@M1ST3RHYDE]

If l have a coil of wire wound in an upward helix around an iron bar & I wind an additional coil of wire back down (1,2,3 or more passes) would thereverse direction of the windings produce a stronger field or would it just decrease the strength? Thanks for any help.

[@tonymac96]

Just to clear the smoke...at 7:33 you show the coil connected to the positive side of the battery at top and the negative side at the bottom. This truly means that the current will flow from the bottom of the coil to the top (from the negative to the positive side of the battery). Hence, the North pole a the electromagnet will be at the top and the south pole will be at the bottom. Is this correct ??? ...

[@saheelwagh7438]

well look, current flow implies motion of particles. Such a motion is bound to create some effect. (think in terms of conservation of mass and energy). This effect might be magnetism. I in no way claim that my answer is accurate. Just a try to satisfy my own curiosity :D. I'd be glad if someone provides a definite answer

[@VisualBasic6]

im responding to this msg just to ask you a question ... what dos affect the power of the electromagnet ? is it the voltage, the amps ... ? im making a coilgun and i need this info to make one has efficient has possible thanks ! ps sorry for my bad english im its my 3rd language

[@EslamMohamedX]

thank u very much or this marvelous explaining .. as to direction of current flow wether from +ve pole ( conventional current ) or -ve pole ( electrons ) , i think it is the same " theoretically ", but actually - as u said - current flows from -ve pole ( electrons )

[@ourtrashcans]

@derekowens Why don't we just follow the electric fields. Since there can be no magnetic field without an electric one. You jump right out of an electric flow into the magnetic result without explaining the electric result. This is exactly why everyone has been so confused for centuries.

[@idster7]

so you said that you use direction of positive current in the right hand rule. so, if positive current points one way, really, it is electrons pointing the other way, and a left hand rule could be used to describe the magnetic field in terms of electrons? is that right? thank you, mr. owens

[@RandomsFandom]

Electrons move to the negative side building a influx of negative potential which causes positive field

[@tonymac96]

Cliffr2011 ....Just imagine that we still be teaching that the Earth is flat !!!! ....There are things that do not make sense...and electrons (current) do moves from the negative to the positive pole of the battery !!!

[@Layarion]

So they're both the same thing, except one stops existing when it's not charged?

[@Benchandbeyond]

Why do we still teach conventional when we know its wrong? I understand it had a mass following before it was found to be incorrect but we really should be moving away from this.

[@terminator847]

So what causes a current in a wire to produce a magnetic field? I was always told about the effects of the magnetic field and its sources, but never what actually causes it.

[@davidswinton3522]

Positive goes to the power and uses the power. Negative is fed the power. Think about it.

[@jonflynn2010]

hahaha if you turned the wire around that would mean the current of I+ would turn around hahaha that just doesnt make sense hahaha

[@jstgamerz04]

I am in 6th class but easily understood it thank you I was interested in this tipic

[@dusklighterz]

hey derek, youre following the coventional flow!..but if its an electron flow current, the left hand rule appplies

[@scaleop4]

i have to say that you do explain things incredibly well. you take your time and not rush it. keep em cumming.

[@emilyschwartz7213]

Your drawing is damn good

[@JohnAyala18]

Thanks for the videos! :) Save us a lot trouble when we miss classes.

[@cruz0823]

I love youre videos Derek. I've been reading a book about basice electronics and when I dont understand something I watch youre videos!

[@jieyupeterchen9769]

simp

[@VivianSudhir]

Very clear ideas, thank you sir

[@EduardoMartinez-dm5pp]

There's something you are not mentioning... there is something called "Hysteresis Loop" which represents the "MAX" amount of magnetic field that you can generate with an electric current... so there comes a moment in which you cannot make anymore magnetic field in spite of how much electrical current you apply... the material becomes "saturated" and there cannot be more magnetic field.

[@mohamedamjadakram]

I'd like to thank you wholeheartedly for all your valuable contribution. I learn a lot from your videos and I am very grateful. THANK YOU SO MUCH!

[@murugananthammuruganantham5036]

I had try like that,but battery is over heating so it occur any problem. for example battery is burn or etc.... sir pls give explanation why is battery heating.

[@derekowens]

If you are trying to make a simple electromagnet, then you might need to use a longer wire and more coils. If you are using a short wire, or very few coils, then you essentially have a short circuit, and that gives you very high current flow, which can generate a lot of heat and can damage the battery. A longer wire will have more resistance, so less current flow, but will allow for more coils, making a stronger magnet. Hope that helps.

[@forcedtocreate]

If it's the electron that moves. Say that and leave it at that. Simple.

[@mystiqkc]

Awesome video!! Thank you very much!

[@DANversusWTP]

I'm not sure why an electric current has a magnetic field in the first place. Is this just a fundamental property, or can it be explained? It seems like it may have something to do with angular momentum because of the right hand rule, but i'm not sure. b

[@derekowens]

From what I understand, it is a fundamental property. It would be like asking why a mass has a gravitational field. That is simply the way God made the universe. Newton himself said that even though he had discovered the equation for gravity, as to *why* it existed, he could not say. His somewhat famous quote on the matter: "I feign no hypothesis."

[@doodelay]

+Derek Owens invoking god to explain what you don't know will limit countinued understanding. Better to just say that you don't know rather than using the "god" place holder.

[@blancaroca8786]

Initially it seems magical the connection between electricity and magnetism and the mathematics of the fields is very elegant and as simple as logic allows. Spacetime einstein special relativity essentially demands something extra associated with electric theory ....hence magnetism. Why doesn't gravity also have similar?! Well there is another way.... bending spacetime ..general relativity.

[@joyisrawrsome]

How to change direction/flow of electrons?

[@derekowens]

@ourtrashcans Oh, right, I see what you're saying, and that's a good point. The electric and magnetic fields really work together, but that's beyond the scope of this course. I would love to dig into that more, though, and make some videos on that also at some point. When I get some free time....