Thermal Conductivity, Stefan Boltzmann Law, Heat Transfer, Conduction, Convecton, Radiation, Physics

[@TheOrganicChemistryTutor]

Final Exams and Video Playlists: www.video-tutor.net/

[@railx2005]

Somebody give this man a Dr title

[@FredrickKazembe-lb3sg]

Not yet understood

[@ritajam322]

This guy is great at all the things he teaches, whether chemistry or physics or mathematics, you are great at what you do. Thanks for everything.

[@retsepilemothepu1396]

My Physics improved from 50% on semester test 1 to 97% on semester test 2🎉🎉 Thank you sir, I have nothing to offer. I’ll thank you properly in the future.

[@aaravmalde3414]

here i am, reminding you, to thank this man properly in the future.

[@lizwiz9931]

@@aaravmalde3414 🤣🤣🤣

[@Đeath_Himsełf121]

​@@aaravmalde3414ikr lol

[@balajothiadithya3144]

my man here is a life saver.always makes physics easy for me

[@nhaz652]

i want to cry, i really do. this has been very difficult for me. i am an adult learner who is struggling to find my right pace to study after 5 years being in the workforce. please pray for me.

[@Carusot]

Good luck, failing is always a lesson so don't give up and learn from your mistakes.

[@nhaz652]

@@Carusot appreciate ur advice!!

[@chomosuke0720]

You're in my prayers man hope you're doing well

[@jakeellender9858]

Good luck! I hope ur doing better

[@jasondean88888]

The only statistically significant result that I have found, related to the effectiveness of prayer, was published by The Pendleton Foundation. They are a pro religious organization. Their research showed that in most cases, there is zero impact of prayer. But there was ONE situation in which they noted a statistically significant result. When people KNOW that they are being prayed for, on average, their outcomes are WORSE than the control group. So, if you really want to reduce someone's chance of recovering from that heart surgery, just tell them that the whole church is praying for them. There will be a certain percentage of people who believe that prayer will help, so they don't give a full effort at following the doctors suggestions for recovery...and why would they? They firmly believe that their church has cast a magic spell, by talking as a group to an invisible super hero, and they are "humble" enough to think that the most powerful being ever is going to change their "perfect plan" based in the temporary wishes of a few dozen people who want reality to be a little different than it is. Seriously....I'm so tired of being surrounded by this type of "problem solving". I'm glad you're trying to learn complex topics, truly I am. Keep your magic out of the lab. I'd really like to not return to the era when people like me were burned because they pointed out things like "Prayer is not a reliable tool for problem solving." You mean well, I know. My great grandma was old enough to have met someone who sat in a jury for a witch trial. I met my great grandma. Think about that. Given the right location, I'm one person away from having been able to talk to someone who sat on a jury, in America, where someone was tried as a witch. Just because religion is far more tame than they use to be, that is no reason to forget how they behaved when they had all the power. So please, keep your religion out of my science class. And I'll refrain from walking in to your church and running tests on your holy water to determine how much "holy" different preachers attain.

[@timetraveler0828]

This is the best account on this platform, I believe. I'm reviewing for physics bowl, and I found out that a lot, or most, of the stuff in that competition I haven't heard about them yet. And I found every video that I would like to see, just watching videos from this account. Thank you so much.

[@yasmin-nh4zq]

thank you it really helped me in physics, i have a physic test tomorrow and you are a life server thank you

[@wintutorials2282]

You explain it so well. Thanks. I tried to explain it, and even though I’m being complemented on my explain-like-I’m-5 skills. I wasn’t able to explain this topic. Thanks

[@joelleking4098]

I just love this man's way of explanation

[@Neverathing]

this man is the savior of any physics students

[@brendonsmith1364]

This video is gold for a HERS Rater/ Energy Auditor. Thank you!

[@JosephOladepo]

Thanks for the simplicity in your explanation. It really helped 🙏🙏🙏

[@juliagabrielle5655]

helped me throughout chemistry; & now helping me on my physics series haha you’re the best thank you sm! I dont think i could have done so well on ochem w/o your help!!

[@syria6033]

I love you so much, this helped me so much. You explain it better than my teacher suprisingly.

[@williamsakala8137]

No words can describe how this man has changed people's life academically your life is a blessing 🙏🙏 to the all world...Thank you for your dedication 🙏

[@vjosaveselaj3788]

this video was very helpful. You're a life saver. Thank you!

[@oximas-oe9vf]

13:20 sometimes we use R = L/kA when it's not a unit area that is the bigger the area the lower the resistance just saying as to not cause any confusion.

[@lifezap2484]

I’m starting to believe this man knows everything

[@jnpkzwjx]

He is really knowledgeable in many fields

[@user-rt6ij3rz5y]

I really love you man I wish there was an arabic cc so my arabics friends who don't know much english can use this magnificent source What a loose for them

[@isabelleambrose9293]

Front what I've heard ai could translate it to Arabic if he wanted to the translation would be love and considering how good he is at explaining I think the fact the ai is translating wouldn't be a problem

[@mariaagonzalez4168]

This guys voice makes me sleepy 😴☀️💧

[@RiccardoRiva997]

me too but I've to listen ahah

[@wintutorials2282]

Speer the video up to 1.5x, that sounds natural

[@Math_Queen]

You have videos on Heat Transfer?! How did I not find this during the beginning of the semester?! Oh my goodness! xD

[@HarleyKat88]

Thank you for all of your videos!! You are an awesome humxn to put so much free educational content out into the world! I've had such shitty professors over the years and your videos have helped me beyond measure. Good vibes to you forever!!!

[@birdcage2425]

You can not teach yourself introductory material? The university system is a joke, it is not the best and brightest any more.

[@Jules-69lol]

What's a humxn?

[@jnpkzwjx]

@@Jules-69lol *human

[@Jules-69lol]

@@jnpkzwjx i know it wasn't a typo

[@rorycarter6948]

someone please explain why I've never had a good physics teacher/professor? This channel is literally the only reason i understand physics

[@dimakatsokhoza3223]

This video was super super helpful. Thank you very much!🤍

[@SomethingAbtScience]

This comment was very helpful, much appreciated!

[@jasminewang7301]

Many thanks for this video! Really helpful

[@quartzar]

such a brilliant teacher:)

[@warstechnolearn55]

Sir thank you so much for your good teaching.... I am so grateful towards you sir ❤️❤️

[@SomethingAbtScience]

are you just a bot or something

[@galaxypirateofficial]

Thanks for making physics to understand easily

[@manuboker1]

Wonderful Heat Transfer lecture ! ! !

[@sarcaastech]

thank you so much sir... was waiting for this from a long time... sir when mordern physics lectures will be coming ?

[@moreefn]

May god bless you🥺🤝💛

[@JoJo-bz1tg]

i think your video is very helpful

[@AHMED-if2dy]

i really really love you man ❤❤❤❤❤❤❤

[@tedgraves6366]

Q: For the passive transfer of heat, steel appears better then glass; which radiates faster. . .? Solar energy issue I am working on.

[@yassine321]

Yeah for better performance and to get the maximum power from your solar energy your solar panel must stay cool

[@thomaschamper9897]

@@yassine321 A little too late my friend.

[@hagnibof7675]

Better late than never

[@syedkareemnawaz1434]

Very beautifully explained...

[@nancyphiri6705]

God bless you sir

[@JohnDoe-gb6co]

Awesome video, the only thing you could improve on is to put titles at the top of your blackboard, it really helps to keep focused

[@JoJo-bz1tg]

i agree

[@emilyzheng7559]

Way too much ads. And probably one if the few channels that put ads in the middle of teaching. But thanks for uploading anyway

[@paboracha1346]

Thank uu fot making videos. This really helps us.

[@Mulinful]

Could you work a problem showing how to calculate the time it will take for a piece of meat to heat up to 165°F , when placed into an oven of 350° F . From a refrigerator (say 27° F ) ??

[@sammankashif258]

thank you for this really helpful video

[@greedy8016]

Interesting video. I have a question: Does an object lose its heat due to transfer of energy while time passes by? I mean, for each amount of energy a hot object transmits, it loses its heat too? If so, the faster it loses it energy, the faster it gets cold. Sorry for my ignorance and my bad english. Thanks in advance.

[@iamparitosh]

Yup heat is a energy transfer only

[@danstone_0001]

This is why they fill modern hard drives with helium, because it's lighter than air, so cold heat stays at bottom of drive and hot air gets transferred out from the top of the drive via conduction.

[@ahnafradi1942]

U r tooo Cooollll! Thanks for these awesome videos!!!!!!

[@specom9161]

At 28:57 why we put the same (e) for both air and sphere sence we have tow different materials??

[@1683chukka]

real algeria e defined for body not for surrounding in the question

[@dossube]

The material of the sphere is unknown so I guess the e-value was randomly chosen to be equal to e-value of air at 275K, which is about 0.42.

[@nathannicolas2166]

Thank you for the incredible help! However the amount of ads is extremely irritating when trying to focus on such subjects

[@ditotodi7805]

I don't see even 1 ads, you sure?

[@baraaahmad7738]

adblock is a thing

[@jasondean88888]

I saw 2 ads in a 30m video. Just leaving this info for future generations. I'm not sure what quantity "so many ads" is, but my specific experience in 2023 was spending 5 seconds to skip an ad twice during a half hour lecture. In the college classes I've taken in person, I have regularly lost 5 to 10 minutes per hour to other students deflecting the class from the goal of learning the specific topics. Roughly 1800 seconds of information with (lets round up to keep it tidy) 18 seconds of ads. 99% efficiency at delivering uninterrupted information. I challenge anyone to beat that in a classroom.

[@NathanNicolas-od7cn]

I'va had problems with the amount of ads on youtube. Maybe this is because I am watching it in France. KZbin is the problem, not the channel. I now have Adblock and KZbin Vanced. I won't be paying a subscription to youtube, ever.

[@farhanabbe9412]

Ily trust me man u r so helpful god bless u

[@jonathansanchez8802]

Great video!

[@Memesstudio10]

Thanks for the video 👍

[@esbornrimapu1541]

Thanks for your wonderful teaching. Please may you help me with this question? The question is: Calculate the total heat required to convert ice at -12 ⁰C to steam at 105 ⁰C. Please help me out with working out shown.

[@luluvettel6763]

Idk if the question is correct if it is I have no idea how to solve it but, if u are given the mass of how much ice to convert u can apply total heat energy formula of nct where n is moles of water c is specific heat of water and r is change in temperature which is given we take water of course as ice and steam are water

[@jasondean88888]

I would normally be happy to help, but answering the specific of a question feels like helping you cheat. There is too much missing from the question. I'll re-read it and see if I can post something that might be helpful to future people who read this, but doesn't just short cut a specific answer to a specific test question.

[@jasondean88888]

So... The specific heat capacity of water is 1 degree Fahrenheit per pound. What that means is, if you want to raise the temp of H2O 2 degre F, then you need to add 1 BTU worth of heat energy. However, there is an extra cost when you cross a phase transition, like going from ice to liquid or liquid to steam. I wont give you the specific numbers, because they won't be important unless you're trying to cheat at a specific question. But...I WILL tell you that to go from 32f degree ice to 32f degree water require ABOUT 200 BTU instead of one. To go from 212f degree water to 212f degree steam is ABOUT 900 BTU instead of one. This is why phase transition is such a powerful way of moving energy. You can go cut a block of ice from the mountain and put it on a train and ship it to a city where an "Ice man" makes deliveries every day to people who have "Ice boxes". And it's because ice has over 20,000% more cooling power than 32f degree flowing river water. This is why huge cities run apartments on steam radiators. For every pound of steam that is moved to the radiator you get over 900 pounds worth 212f degree water. It takes a LOT less energy to move 1 pound of steam than 900 pounds of hot water. Phase transition is everything. The point your professor was trying to teach you was that a lot of energy can be stored in the phase transition of materials. Be it water or steel, the same basic concept apply. Yes, I used Fahrenheit on purpose. Ive spent the time to break down what your teacher was trying to teach you. You will have to go figure the specific answer yourself.

[@jasondean88888]

​@@luluvettel6763There is a far easier way. His teacher was trying to teach them about the importance of phase transition and the massive amout of energy that can be stored when converting from one phase to another.

[@kayla177]

At 22:07, why did you use 4piR^2 (surface area of a sphere) rather than the area of a sphere, piR^2?

[@mikakorhonen5715]

His example is three dimensional object and will radiate energy (heat) equally to every direction.

[@kojomello2110]

You mean area of a sphere, which is 4/3 pi r 2

[@AB-gu9ui]

it emits heat from its surface

[@jumazulh1]

@@mikakorhonen5715 I still don't understand.

[@ianlin2189]

The area of a circle is πr^2. The volume of a sphere is 4/3 πr^3. The surface area of a sphere is 4πr^2, which is what is needed.

[@nkereuwempaul9506]

Thank you so much ❣️

[@mohammedbaramim7639]

thanks life savor

[@CasualCreateOr]

Seriously it is though

[@jufriazziq]

isn’t convection equation like Q = h * A * ΔT 7:00 where does l comes from ?

[@Animetrader_10]

Thank you ❤

[@angelmpc1725]

For the last question how to you calculate the true time with the instantaneous change in the temperature of the body, thank you.

[@philangezwiliwamtshengu1909]

Is it not R=L/KA?

[@theboogiegamer3872]

No this is not current electricity

[@Jt-zy5dl]

@@theboogiegamer3872 lmaooooooooooo

[@ChiariDebKirkpatrick]

If I hang a 2’x2’ metal wall decoration above a ceramic wall panel heater would how would it affect the heating of my room?

[@kaustavsengupta8757]

Heating will not be that effect, but if your metal wall decoration is made up of iron or something like that it will increase the corrosion factor. You see rusting or corrosion of metal is directly proportional to heat. Just keep that in mind.

[@freetotryit]

Wow..I have watched this 2 times and still can't wrap my head around it. I'm trying to figure out if a heat source of 600f is 6 inches away from a sheet of 032 gauge aluminum and it's 100f air temp, how hot will the aluminum get? Then I need to figure out if a sheet of 1/8" vinyl is 1" away from the aluminum what is the max temp the vinyl will get? I have tried to figure this and my brain is stumped. My expertise is in other areas. Any guidance to offer?

[@mikakorhonen5715]

This is basically new stuff for me too, but sounds impossible to solve without knowing size of the heat radiation source.

[@kaustavsengupta8757]

I can answer this question, but don't know whether it will be fruitful to you now.

[@josepipa2672]

@@kaustavsengupta8757 you should have answered it, it can help other people.

[@emmanajibi720]

I appreciate your videos

[@soulbladeA46]

Good video s 🔥🔥🔥🔥👍👍👍🙂🙂🙂😆😆😆

[@upekshad5765]

Thanks

[@iglesiasleonardo1742]

The energy that's been transfered throught the glass window each second goes straight into the air? Or does it acummulate near de window then gradually goes to the air?

[@freebiecatch5103]

Hello, at 25:11, the answers were both positive and negative. Could you please explain how you arrived at that? Thanks

[@stephenhawks3941]

FreebieCatch one was negative, since for absprbtion we have to use a minus sign

[@adityasrivatsa4115]

for emitting we have to use -ve sign. All we're doing is seeing the NET ENERGY CHANGE. so if body is losing energy,it's obviously -ve sign

[@AB-gu9ui]

First value is how much the sphere is losing therefore its -ve and second value is how much heat it is gaining therefore it is positive

[@chethan4152]

We did aluminum thermal Spray on boiler wall, after the coating the emissivity reduced from 0.9 to 0.4 but we observed the temperature of the surface got increased from 220 to 250. How it happened please explain??

[@triheatout6116]

compute the amount of heat needed to drop the temperature of 100cans of milk from 32c to 25c , assume specific weight of milk to be .99kg/L. specific heat of milk is .93 BTU/lb F. can someone help me with this question, thank in advance

[@daca1320]

If heat sink is distanced 2-3mm from the heat source will this help reduce the heat of the source

[@salamtang2837]

That is very interesting lecture thank so much

[@J-swishJ-swish]

Quick question do you offer videos for heat transfer line fouriers law thermal resistance and mechanics of conduction

[@piamontedanselanthony8812]

Hi got a problem : the question is There is a 275ml of hot tea that we like to cool down before drinking the tea is currently at 380k and we'd like to cool it down and bring to 360k how much thermal energy has to be transfered from the tea to the surroundings? my problem is i don't know what equation i would use tnx in advance

[@adonisg.j7430]

If you could measure the mass of Tea use this q=mcΔT Note∆T will be (-) assuming (c) of water to be same for tea=4187J/kg°C

[@PostTraumaticChessDisorder]

Why is K used to represent the rate of conductivity? Very confusing because K is used in many ways. I've learned to use greek letter Lambda

[@ibewarrilawrence3686]

K means kelvin which is stand for temperature

[@PostTraumaticChessDisorder]

@@ibewarrilawrence3686 exactly, so it's very confusing to use it to specify rate of conductivity. Makes no sense. Just use lambda instead

[@AB-gu9ui]

isnt lambda used as the wavelength symbol tho

[@ritishkandel9896]

Thanks for everything!

[@islamicbrotherhood9574]

But i was told R=L/KA

[@shoofky]

If I have a foil lined lunch box that I want to keep cool how should I go about calculating the heat loss due to radiation?

[@edwinberaud1646]

convection too. air is also cooling it.

[@unclefrankindia]

Thank

[@algatore1892]

why the power and heat transferred through object has the same formula?

[@malamamuleba1576]

For the suns heat energy to reach earth there are air molecules, so is it correct to say radiation is also heat transfer through fluids?? Or the sun's heat energy reaches earth through convection and radiation.

[@jasondean88888]

The air density of space is effectively zero. Yeah, there is a tiny little bit, but it's truly not enough to worry about unless you're literally working for nasa and need to account for every tiny parameter possible. Space is the closest thing to a perfect vacuum to exist. This is why the ISS has such a hard time staying cold. They have no way to lose heat other than radiation. Convection is not an option that even enters the discussion for NASA. And they are close enough to Earth that the the air density is hundreds (maybe thousands) of times greater than interplanetary space.

[@miguelntap8406]

Excuse me teacher I think there's and error of conversion in the first example 14cm in m is 0.14m and not 0.014. So the answer is 108W

[@stranger9774]

it's 1.4cm not 14cm :)

[@danieliosif3232]

Hello! Therefore I need a power source within the sphere to generate 44.5W every second to maintain the sphere temperature at 27 degrees? Of course, in time the surroundings will heat so the demand of power source will decrease. For example, if I would have a heat source generating 80 W within the circle, can I found out how much of this power is loss at the interface with the surroundings? For example the sphere is made from concrete and this concrete sphere is into the ground. Both have 14 degrees Celsius. If I need 80 W to extract from the ground through this sphere, can I find out how much of the energy I can obtain actually, to say "My needs are 80W, but I can get only 60W from the ground"? I am studying geothermal energy (energy foundations as diaphragm walls) and I don't know exactly what's happening in the ground because the method I am using consist in treating the pipes within the diaphragm walls (which are in the ground) as heat sources, followed by measuring the exchange heat at the interface of concrete/ground. But I don't understand exactly what this means. I would really appreciate your answer!! Thank you!

[@fruxxlucy6923]

I lost 99.7 percent of my brain cells tryna understand this

[@danieliosif3232]

@@fruxxlucy6923 :)) I didn't know so many about this to ask a simple question

[@Harsh-h6m]

"convection" spelling is wrong in the title

[@debojitacharjee]

What is heat radiation and is it like electromagnetic radiation? Heat can transfer in vacuum also but how? When anything is heated then its molecules vibrate rapidly but why anything that comes near that object also heats up? Is it something like electromagnetic radiation?

[@kaustavsengupta8757]

You are right but you too are confuse. Let me explain it to you in simple terms while not making this complicated. You see heat is nothing but a form of energy. Energy can be of different form like heat, chemical energy(petroleum), sound energy, radiation etc. Whenever you give energy to some object, electron inside the object start vibrating, hence resulting into collision of atoms or molecules of the object. This collision of particle of object results in increase of internal temperature of object. Now coming back to your question, when we applied high energy electromagnetic waves, according to E = hv( Planck equation), electrons inside the object absorb this energy and rise to an exciting state( in simple terms they start vibrating). Due to this vibration of electrons which results into increase in temperature of an object. The best example of heating with electromagnetic waves is laser. You see by laser( which is nothing just electromagnetic wave) we can increase the internal energy of object which in results causes the burning. Sorry for long post

[@debojitacharjee]

@@kaustavsengupta8757 thats alright but how this heat energy travels? I can understand that light is also energy but it travels as emission of photons but what is heat? At what speed heat can travel in space and how far?

[@kaustavsengupta8757]

You still getting confuse, heat is just another form of energy. Like ice is just another form of water. Look man infrared rays, they lie in electromagnetic waves but can warm bodies. You see every energy can be converted into heat. And every heat can be converted into energy and electromagnetic energy.

[@debojitacharjee]

@@kaustavsengupta8757 You are only theoretical but I am looking for a practical answer. What is energy? How energy can take different form? If infrared light is a form of energy then it's made of photons but what form of energy comes from a cup of hot coffee because that doesn't emit light? Light has a speed but what if the speed of heat energy? It must have a speed because the heat is coming from the sun though empty space. Is heat similar to electromagnetic energy (radiation)?

[@kaustavsengupta8757]

@@debojitacharjee look buddy, energy is nothing but work done to move a object displacement. In electron this displacement is nothing but vibration. And as far as your hot coffee mug radiation energy is concern, when you boil the water for making coffee, you have given the chemical potential energy of LPG gas ( assuming you cooking in cooking gas) to coffee. This energy is then absorb by water molecule and they start vibrating. And then with adequate vibration, they were able to breakdown Hydrogen bond intermolecular and started rising into gases phase. And this water vapour pass down the energy by interacting with other molecule of air, hence energy is transferred to surrounding. As far as you speed of energy is concern, energy can have any given speed given by circumstances. Like it can have static speed egs( electrostatic energy, chemical potential energy) or it can have speed like(kinetic energy). In short energy is nothing but amount of force to move an object with distance x.

[@syedkareemnawaz1434]

I have 70 Deg C Coffee extract of 500 Litres. Want to bring down its temperature to 10 Deg C within 15 Mins. To achieve this I am supplying the chilled water at 6 Deg C. So how to find out the Chilled water flow rate required to achieve this. Please help.

[@kaustavsengupta8757]

Brother that's is differential equations, I can solve this equation easily, but I will encourage you to search "Differential Equation Newton Cooling"

[@jithinajith4295]

Which textbook is this?

[@AhumumuzaOscar]

That's great

[@kaustubhprakher5831]

Correction - thermal resistance is l/AK

[@todddavid9133]

Sir I would like to like all your videos without watching them but there is no way I can do that.

[@shreyas5273]

You should watch all of them

[@Todaywalnut]

Don't do that, your knowledge will increase even more if you watch and like his videos

[@vusimatimbe1938]

What's the SI unit for the R value??

[@burhanuddin959]

Ohm-metre. In dimensions it would be ML^4T^-3A^-2

[@lindumuzishabangu1207]

On the sphere question (A) I keep getting 44.51 as my answer pls help

[@J-swishJ-swish]

I tried looking for them but couldn’t find anything

[@elizabethblack3863]

My deeply deranged downstairs neighbour has found a way to administer burns, pins and needles, static shocks and a very unpleasant vibration through the floor, with some sort of portable device. What could it be? Please answer as the police don't believe me!

[@masonroberts3461]

Get rid of your carpet or smack him up 😂

[@norazniahmadnasarudin6416]

the title should be convection,not convecton

[@davisnoah347]

Nope. It's supposed to be connection. Convection is not even a word 😂.

[@samfitness7198]

​@@davisnoah347it is

[@juholaaksonen7455]

I'm trying to solve this in a dynamic environment and would love a skype session to mirror ideas =D

[@zednes2065]

Is that a D or a triangle?

[@ianlin2189]

A Delta symbol, which looks like a triangle. It's basically means "change in."

[@DrinkingmeadwithsamAdams]

I do have a question , when you made the comment that the suns heat is transferred to the earth mainly due to the void of space. We are learning with CMIP6 that there are other factors to be considered, What about plasma, CME dust and solar winds, in space. Could there also be an effect other than just solar radiation in the conduction of heat energy toward the earth? Just wondering.

[@qinlian5150]

Where is the 0.35 come from?

[@francine8563]

Sir, 14/100 =0.14m isn't it?

[@Karl_Scharl]

Dit is interessant groetjes Luuk

[@lalalalalala.1234]

I like

[@reyhana6870]

Any one have questions about (E = σ x T4.) this formula l need it because I have exam 🙏🏻

[@suhrabjorashev1500]

area of circle isn't it п(R^2)

[@TheOrganicChemistryTutor]

Yes, the area of a circle is pi(R)^2

[@jasminewang7301]

But the surface area of a sphere is 4piR^2