What is Temperature?

Explains temperature on the atomic scale and all of the different scales – Fahrenheit, Celsius, Kelvin, Centigrade. What 0 and 100 means in each of the scales. A distribution of speeds and how that relates to a temperature. Boltzman’s equation for relating energy to temperature. What absolute zero is and why it is important. An example of heat transfer with an interactive exercise. Heat conduction, convection and radiation are explained.

[KONAMAN]

What a teacher this guy is. Like Feynman, these guys take complex stuff and make it real world practical. Great stuff.

[michaelschwartz]

Just found this channel, I'm binge watching!
Excellent channel Professor!!

[MultiPetercool]

A discussion of how induction cooktops work would be a great follow up for this lecture.

[zzador]

I have understood everything from your videos so far and I didn't even study nuclear physics. I think this statement says everything about the quality of your teachings. PS.: Mad respect for your ability to write backwards. I bet you trained it a decent amount of time.

[alext]

I give him credit for explaining temperature changes by moving this hand from our left to our right, even though that is backward from his perspective. Almost everyone will do the opposite.

[phugoid]

Of all your videos, I must confess that this was the only one that I found difficult to understand. So many questions

[RaderizDorret]

32 for the freezing point of distilled water and 212 for the same water to boil makes sense when you realize Fahrenheit the man wanted whole numbers for ease of calculation. consider the 180 degrees difference between those two numbers, and you'll see it's a very convenient number. 180 divides easily into 2, 3, 4, 5, 6, and 10 without the need of fractions or decimals. It's the same reason why a pound sterling was originally divided into 240 pence. Given that it was THE first standardized unit to measure temperature, on top of that (1724 vs the 1790s) it makes sense. And the main reason why the US stuck with the older English measures is because of the English themselves: we were set to go Metric but the Brits sank the French transport carrying the weights and measures we needed to properly calibrate everything on our end. By the time England went to metric, it was (and still is) deemed to expensive to wholesale adopt Metric for daily life... but we did redefine our customary measures based on metric and it's not only easy enough to convert between them, but even daily household goods like measuring cups are marked in both systems so it's a more or less moot point.

[larrykent]

Thank you, good stuff presented well.

[Austrochad]

i wish i had such a cool teacher like you are one, back when i went to school :/

[quenchize]

0 Fahrenheit is chosen because a mixture of water ice and salt will automatically settle at that temperature making it easy to reproduce. Body temperature was supposed to be 96 so that there would have been exactly 64 divisions between freezing point of water and that.
I am not a fan of Fahrenheit but I think using a solution / reaction that always settles at a fixed temperature is a neat idea.

[guyfredrickson]

Interestingly, radioactive decay continues at 0K (absolute zero temperature).

[jeffreycordova]

@11:00 Ouch! I shouldn't have been cooking while watching this.

[Cspacecat]

Conduction, convection, radiation, and reflection are important in heat transfer.

[hermanrobak]

6:03 Nitpick: A 40mph wind is not a "breeze". It's a storm.

[MultiPetercool]

My High School Physics Teacher defined temperature as “A vector description of the thermal gradient”

[ylette]

Air molecules moving at 500 m/s at room temperature? There sure is a lot going on that you don't notice.

[allyourpie]

Baby don't heat me! Don't heat me...no more!

[billchaffee]

It seems to me that the average air molecule would move at approximately the square root of 2 times the speed of sound. If on average air molecules collide at a 45 angle, the sound will travel slower then the average air molecule. Nitrogen molecules would move slightly faster than oxygen molecules on average because the're lighter.

[Paraselene_Tao]

8:50 haha, that body temp in Fahrenheit ought to be +100 and not -100. That's a cold person!

[abyni]

I think the main way is radiation, when a molecule abaorbs radiation it moves, which in turn produces electromagnetic radiation and so forth i.e conduction, when atoms move they need more space, so they become less dense than the fluid of molecules around them, and due to gravity they get pushed up, all due to radiation, but how radiation moves molecules or how molecules absorb radiation is beyond me, but it has to have to do with electromagnetic fields interacting with the fields of the atoms i.e their constituents electrons and protons. But it is just a hunch that I don't know its truth.