Induction - An Introduction: Crash Course Physics #34

[@crashcourse]

We made quiz questions to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: apple.co/3d4eyZo Download it here for Android Devices: bit.ly/3TW06aP

[@kimaegaii]

I sped this up to 2.0x speed and I started emitting flux around my entire body. All kidding aside, as a beginner even this is seriously helpful. Thank you.

[@madladdan]

Leaves school: Yesss finally I'm done thank you Crash Course you've been good to me! Starts engineering at uni: Aight I'm back...

[@ChristianGonzalezCapizzi]

I can't imagine anyone who hasn't studied this before learning anything at this speed.

[@fridaaa0]

ikr, they're good summarisers for rehearsal though

[@ritvickrocks]

just revising

[@张帅-e3d]

It is so fast that it confuses people even I learnt about it before. Eventual it is not the speed but the way it is presented which is just to the conclusion without showing how people discovered it step by step

[@dayzyrules1]

play in .75 speed & pause to take notes

[@ramlahassan9761]

The reason why I love crash course is the fact that it doesn't waste your time (in most cases)

[@Chloe-kf1lh]

Lately I've been seeing Shini and Hank more than my own family

[@geeway5923]

same

[@tiamatmarduk8406]

Is that by choice?😂

[@erikziak1249]

It is easy to watch if you know what Shini is talking about. However I imagine what a mess it must be for someone with zero background knowledge.

[@TheMahjohng]

Erik Žiak yeah I haven't studied physics in a while and had to repeat sections a couple of times.

[@Y2KNW]

I barely passed grade 11 physics and got lost almost instantly. :P

[@thijsiee2]

It goes way, waaay too fast for me, even though I have a good understanding of the material. The material is presented too quickly. Some moments to think about the material would be better, to actually internalize what has been said.

[@erikziak1249]

That is why it is called CrashCourse. Feel free to use the pause button and rewind as often as you like.

[@TheMahjohng]

Erik Žiak yup 😂, used that pause button at every formula

[@MrThegreatViewer]

Anyone cramming for a physics test right now...?

[@hanro50]

Yes

[@realdvgarg]

freakin MYP makes us have a 3 sciences test together

[@u13613to]

Kind of same here :') , electronics test*

[@rangkara7201]

Me every physics test

[@joleareed4639]

James Anderson 🙌🙌

[@KingsleyIII]

We're all flux'd.

[@32heretic]

Straight up studying electronic engineering and I thought this explanation is fast, feel sorry for anyone who doesn't have a background in this.

[@32heretic]

Good explanation just talk slower

[@cooldiys3477]

Thank you so much, there are a lot people complaining in the comments but I am honestly so grateful that u do videos like these, as they are so much more engaging and I get a lot more out of them than my textbooks

[@CharlesVeitch]

I am still looking at my kitchen hobs with confusion after this video

[@jamilladambo]

This is very useful when you want a quick review of your course before final exams not for you to learn afresh. I find review videos very helpful

[@duhhuhduh]

I don't know if anyone else picked up on this bit, but she pointed out the opposite of what she was talking about. She said that you can use the right hand rule to know the direction of the current based off of the induced magnetic field, which is right. But, she got the direction of these fields wrong in the second half of the video.

[@johnnyace1300]

Yep! In very poor taste, I rely on this chick, she should have personally edited the video herself and she would have picked it up easily. Crash course wasting my time again.

[@DM-ce6su]

The mistake is at 6:11 for anyone who is wondering. Way too many mistakes in this entire series

[@xlsmafia]

@@DM-ce6su Thank god I thought I was going insane

[@frede1905]

@@DM-ce6su No, it is correct. I know that the magnetic field generated by the current is in the same direction as the magnetic field of the magnet (over the north pole). But the magnet is moving down, so the change in the magnetic field is in the opposite direction. And so you have used the Lenz law in the correct way. However, if I haven't made any mistankes, then I think the example of the loop moving out of the magnetic field is wrong. The change in the magnetic field (flux) is pointing up, just as the magnetic field generated by the current. And that is violating Lenz law.

[@tnt_grieferz9176]

@Strawberry Dobreva Are you serious? We are learning from her that's why... we are here to point out our doubts, science is open-minded dude.

[@modelsin3044]

Wait so crash course is targeted to high school physics students but then they are sponsored by prudential which is aimed towards seniors planning for retirement??? Not the best place lol

[@slowgaffle]

best time to start planning for retirement is when you're young!

[@mannyaustinanderson9608]

I'm going to end up viewing this video more than once

[@churchboy4609]

Try changing the playback speed, it should be an option in the video settings

[@jasonsterlace1369]

At 6:32 the current is backwards. I think it was backwards earlier, too. I really like these animations and explanations, I wish PBS would fix the errors.

[@Sora-ce1zx]

6:32 I think this is the opposite. The mark Xs indicate the magnetic field goes from the front to the back of the screen. If you move the loop like this, the total magnetic flow penetrating the area of the loop decreases. So you can guess the current will flow to create the magnetic field to oppose this decrease of magnetic flux. In this case, the current should go in the opposite direction as shown in the video. Please correct if I’m wrong.

[@enna...]

Every time she says ‘emf’, change it to “voltage” or “potential difference” in your head, they’re essentially the same and it makes it MuCh easier to understand!!

[@jbeanp1]

Yes that’s one of my biggest pet peeves in my physics class; note I’m top of my class but wording is so unnecessary sometimes

[@jadeg1154]

That’s actually not true. You can think of it as the voltage across a battery but not just as voltage because you can’t calculate the voltage when the electric field is “loopy”. They’re similar but not the same. Emf is the line integral around a closed loop but voltage difference would be zero around a closed loop because it’s path independent.

[@daBuzzY90]

@@jadeg1154 The potential is just the gradient of the E-field. Therefore if the curl of the E-field is non-zero, a closed line integral would therefore generally also be non-zero.

[@pedrogaleano6722]

Maybe that will be helpful if you want to grasp the idea, what essentially they are not the same, and it is good to know that when you are deep into studying -let alone before sitting for the exam!

[@enna...]

Pedro Galeano I’m aware they’re not the same, but for basic understanding it’s a great starting point if you don’t have the overall idea - I just found it simpler to understand it this way before going into technical differences!

[@cornelioescipion9930]

Sorry, Do you know why Faraday labeled it as "INDUCE current" or "INDUCED magnetic field"? I mean Why he used the term "INDUCED" instead of "Transmited" or "generated" or "created" or "reflected" or another term ? In Phylosophy Inductive method is in one way but in electromagnetism "inductice current" is in two ways so this term (INDUCE) isn't exact with the physics. Thanks for your answer.

[@ac30428]

At 6:33 isn't the current direction in the wire the opposite of what it should be? Downward Flux is decreasing, so induction wants to increase downward flux which means current should be moving clockwise

[@epicfailled]

Is the direction of current at 6:30 false or did I have a brain malfunction? happens sometimes...

[@sohaibbaig248]

wondering the same thing

[@adrianaselena14]

It's false. She said the generated magnetic field points upward so the current flows clockwise, but what she should have said was that the change in magnetic flux is pointing up, which means the generated magnetic field is pointing down, thus a clockwise current rotation.

[@metitusable]

@@adrianaselena14 Shes just reading from a script and got it wrong.

[@Eyenn_n]

I graduated high school in 2015 but this video wasn’t made till 2016. If the crash course physics series could have been made a few years earlier, I might end up at a much better place (college, grad school, etc) now. And for those who are watching this as you are taking AP physics, you lucky ducks.

[@joejohnson6209]

I love that Magneto makes a cameo. The fact that he is a HeroClix figure makes it even better!

[@euyoro4619]

For whoever is confused. I watched the video 3 times and have fully understood it. Ask me anything, I'd be more than happy to help. And a 5:48 she used the wrong fingers for explaining the rule. It's suppose to be curling finger, either clockwise or anticlockwise, then the thumb will show the direction of induced current.

[@brigham1465]

She says the induced current goes clockwise and counterclockwise, but doesn't say relative to where. For someone looking down from above clockwise IS counterclockwise :(

[@aloevera1269]

This is an excellent opening. I get some knowledge about the topic which makes me want to read more in depth about then. After reading in depth, I can come back to this and rewatch it, and understand it much better. I love how there's no Time wastage. Hate off to y'all

[@joshkaye5303]

Needed to slow this video down to 75% speed to understand it.

[@tabrezahmed1000]

Where did the negative sign on phyb when they substituted it in the emf equation? 6:49 and 7:28

[@cmopmoemo]

This makes a lot more sense if you describe Faraday's Law as e-induced is dø/dt. For a magnetic field (that doesn't change as a function of space) Ø=B•A, as you said. So Emf=dø/dt=B(dA/dt)+A(dB/dt) by the product rule. So a change in magnetic field with respect to time or a change in area with respect to time induces an Emf! This is an easier way to see what's going on for that type of B-field.

[@ozzyg1964]

Hello Crash Course team. If you're reading this, I hope you'll someday do a crash course on art. Not on how you paint art, but how you interpret a painting or a sculpture, and maybe define and explain the transitions in art periods. The composition of the series could be historical. Start off with a retrospective from the renaissance where the perspective was introduced in the painting. How baroque emerged. Look from how impressionism involved into expressionism. How surrealism expressed the subconscious. Because art periods are often linked to historical events or scientific paradigm shifts. Surrealists were very inspired by Freud and his theory of the subconscious for example. It was just an thought or suggestion. I mean, your viewers obviously have a very sophisticated mindset, and this could be very appealing to them. Please reply and thank you for taking the time to read my comment :)

[@verdatum]

Crash Course Art-History would be nice. I know the idea has at least been thrown around.

[@TheMitchy27]

Ozzy g yeah i could see CC Art coming and it would talk about art, music maybe a bit of technology and famous artists and composers

[@tnttiger3079]

If you want something like that, check out the KZbin channel Nerdwriter. Thank me later.

[@ringocash6143]

At 2:52 the magnetic field and area of the loop should not be perpendicular but it should be parallel so that cos(0)=1

[@Voidward]

I remember checking these out a while ago. This still kind of feels like someone reading off a script as fast as possible rather than actually attempting to explain things. Sadly, I was actually interested in this topic a few days back and as a newbie to this, would have liked a simple explanation of how to calculate the size of coil and magnet needed to produce a specific voltage, but this really didn't help me in any useful way. I'm actually better off just reading the wikipedia entry because I can at least read that at my own pace and go to the relevant sections. This really should have a more visual presentation format.

[@ruweydaaden2329]

try writing down.study.then y will enjoy the video

[@phoenixfromtheashes]

5:54 Anyone else confused by her definition of the right-hand rule here? She says that current is the direction your fingers are pointing, but the graphic says that current is the direction your fingers are curling.....

[@The97gtrs]

It doesn't, the graphic is wrong (again)

[@jscotthatcher380]

today i learned i am terrible at maths but still enjoy these videos.

[@vatsalgupta9460]

At 2:50 shouldn't she say parallel and not perpendicular (cos90 is not 1)

[@marianauroz240]

Vatsal Gupta Yeah I thought the same. Since cos 90 would be zero how is she taking it 1?

[@fatherharveymisty7863]

it's not even cos, it's sin

[@peterlamont647]

If you talk fast enough, you can fool _most_ people, _most_ of the time.

[@juhisangtani5820]

Yeah Everytime she used cos90 equals 1. Equation was equal to 0. 🙄 This messed up my concepts

[@lars_larsen]

There are definately some extremely clear advantages of having the ability to pause, jump back and forth between timestamps, and controll the playback speed of the lecture when you can't quite keep up with the lecturer's tempo.

[@Teo117]

This stuff is AMAZING!!!! THANK YOU 🎉🎉🎉 I absolutely love this information. You are extremely good at this. The information can be troublesome to explain simply, but I always end up understanding. Thank you 😁

[@dutchik5107]

when you have a test on this subject and are trying to study. but are distracted. and this video pops up THANK YOU INTERNET GODS!!!

[@ccc-v-k]

The FBI Is Actually Helping: Part 1

[@IIGrayfoxII]

Hard drives that use a rotating disk are called hard drives. Ones that use memory modules are called Solid State Drives

[@mfmf100]

Man this made me feel dumb.

[@taschke1221]

mfmf100 why? you're reducing your knowledge deficit. it should make you feel smarter...

[@weakgait]

Yeah XDDD

[@GladSadMadBad]

I feel you. It feels like theres so much i havent read yet. Ugh

[@YourLifeWasting]

Starting my electrical engineering degree about to take pbysics next semester im so lost lol

[@shroomzed2947]

Don’t blame yourself. These videos are hilariously bad at explaining things. If you actually want to learn about electromagnetic principles go and pick up a good book on the topic.

[@mohanadebrahim1692]

In the animation at 6:32, I think the direction of current isn't correct. It flows in the opposite direction.

[@alejandroxalabarder7940]

the right hand rule also called screw rule is a three dimension rule (x,y,z), so having the hand just quiet as she does cannot show anything. What she explains in fact can be done with the left hand as well.

[@rasheedaz7059]

I know all about this from my physics teacher at school, except Lenz’s law. And I was suddenly aware of how fast she was going through all of this. I could not understand the rule, nor the experiments conducted to conclude it.

[@rohakhalid1846]

I'm watching this at 4 am and I literally have my physics exam in 4 hours.

[@SIDEKICKONYOUTUBE]

my nose started bleeding @ 3minutes

[@JossinJax]

LOL

[@default0321]

Physics

[@crashcourse]

YES!

[@DrewKF]

+CrashCourse Woo! :D

[@kingviper5700]

That's what I say every time I summarize

[@xyzxyzuvwuvw7633]

zero flux

[@tahoon2009]

EMF vs V Equation deduction illustration was so beautiful

[@rkpetry]

5th graders follow your reasoning until they see something Faraday didn't-at [06:32] the loop of wire begins leaving the magnetic field but only one side-and postulate that flux-crossing must be the local cause, like for Ampere, and reason that is how information of the changing total gets to the wire: input minus output, (inchoate 'bathtub' integration)...

[@jonathanling2421]

Haha. "An Introduction" That's funny.

[@brian-nx8ge]

my worst topic - thanks CrashCourse!

[@leolehrer2408]

Thank you so much! Having an exam soon, this course really helps.

[@orzini7522]

You help me so much, thank you ,Love you⁦💓💓

[@kiarahodan542]

I properly pause this video 100x to take notes in order to really understand the concepts. 10 mins crash course more like an hour in half crash course.

[@analopez2670]

This teaches me more physics in 10 min than a week in class.

[@peterlamont647]

Wow, your school sucks. Just saying. What school is it? Not AZU I hope because I get free tuition there and was planning to sign up for EE.

[@fakjbf3129]

Oh for a second I thought this was going to be Crash Course Philosophy

[@Lightning_Lance]

Me too. I was like "didn't they do this already?"

[@kalpanashedthy3101]

💙LOVED IT❕

[@erasmith2048]

Really helped slot. Thank you crash course. Lots of appreciation .

[@acexperiments475]

Great video

[@D3tyHuff]

2:50 if they are perpendicular it’s equal to zero, just saying. They have to be parallel for the cosine to equal one.

[@Doc_Loc]

give her a round of applause for word play

[@ntana4589]

Well I understood completely. Thanks Shini!

[@LaurensCorner]

This should have it's own drinking game. For example; every time she says 'magnetic field' you take a shot. And when she says 'flux' you have to spin around 5 times looking straight up at the ceiling then dead stop and lower your head slowly looking straight forward trying not to blink.

[@peterlamont647]

You know...The last time I did an impromptu drinking game, it was watching 'Stuck with Hacket'. We took a drink every time he said "obtainium". Unfortunately, in this particular episode, many parts were needed. After about 10-15 minutes we called it off. We had gone through nearly a bottle of vodka already. I think it was the one where he builds a locomotive out of trash and rides back into civilization. Of course, I don't remember because I had wayyyyy too much vodka inside of 15 minutes. Hell, we hadn't even finished pouring our shots when he said it two more times...lol!

[@adubey248]

WOW I love this video

[@alejandrobecerra3698]

I believe at 2:55 you said that if the angle from the perpendicular normal to the loop and the field are perpendicular then the flux will be max, however its when they are parallel, correct me if im wrong

[@zcwan5349]

magneto would be proud

[@kploo4906]

Thank you for your work👍. It seems pretty fast and no time for thinking to thoroughly understand well such a technical things unless the guy was very well in this aspect. Anyway thank you again for trying made it simply for me to understand😁

[@ratssss45556]

Best video for electromagnet!

[@siccovgiffen]

ahhh, so thats why your computer goes completely mental when you put a strong magnet to it right?

[@sunnisukumar]

Good review with helpful and pleasantly colorful graphics!

[@brigham1465]

6:02 clockwise relative to where? It depends on where you're observing from.

[@balbuena1225]

Probably the little magnito standing there

[@balbuena1225]

Wait yeah wtf you're right doesnt work when I did it.

[@invaderz1919]

She shouldn't talk so fast.

[@smqkn]

There are buttons called 'pause' and 'rewind'

[@shuvroroy191]

You can slow the speed .

[@soofu]

Self Improvement it is a lot of info to cover so they have to keep the video short enough that’s it’s not a lecture

[@savagedude3]

Hank would take 5 times as long to get through physics, I think this is necessary

[@yondertf2]

I kind of agree. Moving from topic to topic in sonic speed while giving the viewer (who may well be hearing this for the first time) no time to reflect on what new concept has been introduced is a sure way for information to bundle together in one's head and just come out like a tangled piece of string.

[@terryi8892]

Clear narration.

[@adubey248]

It is the best video to learn

[@bluiflip]

I think her “right-hand rule” explanation is backwards to what is being displayed.

[@vanshajgandhi6845]

Please do a video on semiconductors and transistors and wave optics

[@ibrahimx9560]

love your vids here in crash course 😍😍😍😍😍😍

[@worldadventureman]

The producer of this show needs to have a large current passed through him. How would he ever believe anyone new to this subject could keep up with the speed she is talking at?

[@stephaniej9714]

Thanks a lot for your videos

[@CHAS1422]

Excellent presentation. This is why PBS is so critical to our society. Loved this episode.

[@gwenythjpw]

just play it in 2x speed for a few seconds, then go back to normal speed. it will feel like she's going SLOW now.

[@mazzcollitard585]

That's how one learns slowly and carefully about physics 😁

[@amandag.faller9508]

this is aimed for high schoolers, and here I am as a physics major trying to understand the basics before diving head first into pURCELL

[@ziyadqezbour1502]

thanks for the video you're the best

[@rockyjoe3817]

People complain about how she speaks so fast that no one can collect what she said . For god's sake just turn on the CC English and watch it at 0.75× speed.

[@seangray5897]

I think the hard drive explanation is so god damn interesting

[@gavinwieland3707]

This video is really educational.

[@rishabh645]

Just love your unique accent

[@SpartaSpartan117]

Thought it was titled Introduction- An Introduction

[@rushvi1611]

thank you for the video, was a great help:)

[@sugarfrosted2005]

I thought this was philosophy from the title... also I thought EMF stood for Ectasy Mother F****r

[@crushcollegechemistry]

Love the cartoon Magneto!

[@thomaskeraudren7052]

7:27, where did the minus sign go? is it because when you say strength, you're talking about its absolute value?

[@pedrogaleano6722]

Very helpful!

[@merlina036]

At 7:28 where does the negative sign go in Faraday's Law??

[@georgemacidy1316]

Great video. Thanks.

[@antonioarreola7994]

needed this for my final last week 😢 good video though 😊😀

[@zhen3356]

Thoroughly explained!

[@Uzukavil]

Awesome episode! :)

[@alminabajic4684]

this is just what i needed

[@alanday5255]

I love this video. I wish you would do one on the application of Faraday's Law on automotive ignition coils.

[@AceNallawar]

please make videos for semiconductors and electrical instruments