Intuition behind formula for thermal conductivity | Physics | Khan Academy

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Intuition behind formula for thermal conductivity.
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Опубликовано:

11 окт 2024

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Комментарии : 65

@maily26hana73 6 лет назад

God bless you . Man you are way better than my professor

@mrdejavu96 7 лет назад

finally someone who can explain this clearly on youtube. thank you. this is great

@KnowledgeScroll 9 лет назад

This is exactly the same way I teach it to my students...I love Khan Academy

@DiDongi 9 лет назад

I must applaud you! Your videos are amazing! As are your explaination skills. Keep up this fine work!

@shlokkulkarni8452 3 года назад

He breaks them down into individual concepts and explains them intuitively...great teacher

@sahanravindu7828 2 года назад

thank you,sir

@BridgeWalley 3 года назад

Holy c... Amazing teaching style and approach to derive an expression. Thank you!

@theophilusfabunmi3704 5 лет назад

Great was thinking about how not to forget the formula now I know how it's derived

@KiwiTim 2 года назад

Great video on thermal conductivity. I'm a carpenter developing better performing housing construction. I think one thing that might need adding is that A (area) in the formula is relative to volume, it's hard to visualise with the schematic of a single wall. I was picturing making a wall smaller to decrease A to decrease Q/t but that only works if its positively affecting its area/volume ratio. The sphere is the perfect example, as far away as you get from sphere you get the worse the volume to area ratio becomes right? So a cube is likely the best practical and efficient shape for a building (if you're not keen on building a hexagonal prism or something that complicated haha)

@shavoniilloyd7825 11 месяцев назад

this is actually fun i learnt something new today

@orlandoarriaga7148 Год назад

Just what I was looking for, perfect for my physics experiment to explain this equation

@renushah1866 4 года назад

Excellent

@UNRG-EU 6 месяцев назад

I don’t know if the thickness of the material between can influence the transfer of heat. This will catch up when the material is heated up after that the heat transfer will be equal with thin or thick material between I think.

@sabnaajang6925 4 года назад

Thanks you so much. But I really need an explanation for searles experiment of the thermal conductivity for good and poor conductors

@johnalden948 3 года назад

Excellent!

@CTherm 5 лет назад

Great explanation of thermal conductivity. We have sensor solutions for measuring "k" and it's sometimes easy to overthink what W/mK truly means!

@KrillixKai Месяц назад

Thanks for this video, trying to utilize this to explain thermal conductivity to a lunar landing denier. 🙄

@sumitjaiswal5357 2 года назад

Thank uh so much

@nt5366 Месяц назад

For some reason I am having a problem accepting the concept that thickness of a material slows down the rate of heat transfer. If I attempt to frame the question differently then it might help. If the area on the left was say representaive of the indoor temperature inside a building, then how much energy do I need to input into the building to keep the internal volume of the building at the desired temperature, when taking into account of the changing the variables as stated? Strictly speaking occupants are only interested in what heat energy is being transferred into their walls (i.e. what heat is leaving their living space), and not so interested in the rate or time it takes that heat loss to travel through the fabric of the building before re-entering the atmosphere. I can accept temperature differentials (more thermal pressure), area of transfer (more space through which energy can travel), the rate at which heat energy can move through a material (thermal resistance afforded by the material). But I am most certainly struggling to see how thickness (the distance the heat energy has to travel), has anything to do with it? Any pointers here would be sincerely appreciated👍

@moodsakkad412 5 лет назад

The only reason i was able to pass my Biophysics exam in med school is because of this channel... seriously thank u.

@debasishrout4674 5 лет назад

Thanks khan bhaiya .mazza aa gaya

@mintlata 7 лет назад

These videos help! Thanks a lot Khan

@shaneblackburn8645 4 года назад

Thanks

@amitnayak5869 6 лет назад

Sir, how specific heat different from conductivity or with other mode of heat transfer...

@funwithmadhurjya3486 7 лет назад

thnaks Sir...

@adhilmusthafa4195 3 года назад

Great explanation

@AKSHATPAL1 3 года назад

great

@BrianSokhulu 6 лет назад

Thanks so much for your work

@phonotab7531 8 лет назад

thank you very much

@SauloFurtado-Eng_Mecatronico 9 лет назад

You've done a wonderful job!

@franciskalonjimbuyamba5215 4 года назад

This was a great video

@sachinnagvekar8103 7 лет назад

Helped a lot .... thank you sir

@giadadamiani4453 6 лет назад

Thank you so much!

@asmitaverma6363 5 лет назад

I think it would be silly if I ask a question after this super video. Anyways, my question is how can anyone write so nicely with a mouse???

@xTheUnknownAnimator 5 лет назад

He most likely uses a wacom pen and tablet , or maybe even a surafce \ yoga laptops or some product in that manner :)

@jay.jay. 3 года назад

@@xTheUnknownAnimator True because I have seen in one video him recording this type of videos like that

@georgesamaras2922 5 лет назад

My intuition says: if D: thickness become larger the Heat Transfer lags in time, the absorption rate remains the same, but taking into account the heat capacity of the wall the emmision rate goes down, eg. heat gets trapped and remains longer on the wall increasing the wall temperature and lowering the absorption rate creating a differential equation.

@jessej3275 3 года назад

I have a question about the units.. Usually when I want to understand a term I break it down into units. It makes things intuitive for me. This was especially useful to me in fluid mechanics, thermodynamics and mechanics of materials, ect. But with this equation something feels off. The distance d is expressed in meters and is in the x-direction. The k term has meters in the denominator and is non-directional. These terms (m^2) cancel out the units from the area-- meters in the y direction and meters in the z direction. How can they cancel if they're not in the same direction?? I thought that was the point of cross products in physics- to combine terms that are the same units but are not in the same direction. I see no cross products here. What am I missing?

@havardzackariaspettersen9133 3 года назад

Great video! Stupid question tho: wouldn't the rate of heat transfer also depend of the ability to conduct heat of the different gasses?

@abinashsahoo4369 7 лет назад

what is the thermal conductivity if increasing temp in metal contineously

@umarali367 8 лет назад

thank"s a lot

@danh9676 5 лет назад

Does the formula change is the wall is a box about 1 m cubed, and the the box is metaphorical?

@rhondavachal1471 9 лет назад

Good stuff. Thank you.

@farin7alaei 5 лет назад

Great video, Thanks :)

@sixthkid6 7 лет назад

So if I times Q by the time allotted for temperature conduction, I get how much energy (heat) would be transferred from source A to result B. And If I wanted to calculate the new temperature of A and B it would be new A = A - Q and new B = B + Q

@ivo3185 8 лет назад

What's the relationship between the thermal conductivity constant of a material and its specific heat? If one goes up, does the other one also go up?

@auliai.l.7398 5 лет назад

kinda late but maybe it'll help for anyone still wondering Q = m *c* (T1 - T2) and Q/t = *k* A (T1 - T2) / d

@robertrandom8719 6 лет назад

So you are saying that the wall thickness is inversely proportional to the rate of thermal exchange? What if it where preheated to the temperature in an identical temperature differential chamber and replaced?

@robertrandom8719 6 лет назад

the above statement was said with a Bronx accent : ]

@vaibhavbandal8325 3 года назад

Fantastic explanation as always 😊 but can you please help me with a doubt? When we talk about thermal conductivity, Fourier law tells us how much the heat will flow through a material if it has a unit temperature gradient, but it does not tells anything about "At what speed the heat will flow". If it could tell us that then we would have a chart with the values of speed of heat in different materials. So you told in the vedio that how quick the heat energy moves, but Fouriers law does not tells about the quickness of heat diffusion, it talks abt the quantity of heat diffusion. Please help.

@law-two7327 3 года назад

No, Fourier's law DOES tell us how fast the heat flows. Q/t is the rate of heat flow. Just like speed is the rate of distance traveled.

@MrAE-vx4hg 7 лет назад

I likes your sound man

@gdluacan 3 года назад

but for example, if the thermal conductivity changes with temperature, how would i find the rate of heat transfer? eg. I'm given Ta and Tb and 2 different values of k at different temps, k1(at Tc) and k2(at Td)

@law-two7327 3 года назад

Take the average of the values of k between those two temperatures and use that to find the rate of heat transfer. Unless you have a specific expression for k in terms of T...then you can integrate Fourier's law...

@gdluacan 3 года назад

@@law-two7327 alright. Thanks so much for the help

@deepnarayan3978 7 дней назад

Yadav is on sigma mood

@TomTom-ng8jy 9 лет назад

But I don't see the Time(t) in those thermal conductivity formula though...... Any help? Isn't it k=Q(d)/A(ΔT)? But where does the little t go? "(t)"k=Q(d)/A(ΔT)? They also use W/mK as the unit, rather than W/mKs, s for second. Any explainations?

@d_jvm4081 8 лет назад

Q/t is the rate of heat transfer and can be written as W for watts(energy over time, J/s). So, the thermal conductivity constant,k, is J/s times dx/dT times 1/A which gives the units J s^-1 m^-1 K^-1. But since J/s is W, the units are also W/mK.