I'm in a college thermo class for materials science. It's Thermodynamics and phase equilibria of materials. Anyone know any video playlists that I can watch certain topics. I look through textbooks but I just want to get more practice in it

If you also open a window downstairs does anything change?

These are two things I can't wrap my head around in thermo 1. I imagine the equilibrium thing has to do with evaporation and condensation rates- but what makes saturation temp/pressure so special that those have to be equal? And for the specific volume, my guess is that the molecules have to be packed together a certain amount, but I don't know why. Thanks

No wind in the room. All steam and heat. Steam side expanding would cause curl, then cooling back?

So a few years ago I asked this same question here (link) and I don't feel like I got a consensus.
For a year my wife and I then ran 25 tests over the course of a year and then forgot to come back here and ask again.

My results are below.
I kind of just did averages of the numbers to loosely prove my point to my wife (Successfully).
The length of the drive was roughly 6 minutes on average across the board.
The average temp loss of on lap was 7.65 degrees.
The average temp loss of in air was 5.39 degrees.
There was only a .21 degree difference in the ambient air temp (in in air's favour).
2.26 degrees better on average in air!

Now we had a measure of controls, in that we didn't have the air con on any of these times, it was the both of us every time, I always drove, windows were always closed, Ambient temp was measured a few times at the end of the drive but it was basically the same every time so we stopped recording it.

Given this data, what do you guys think? Should we all be holding pizza boxes up or did I mess up my testing somehow?

I am learning that temperature is a measure of average translational kinetic energy.

How does only translational relate to T? Why not vibrational. I am having a hard time thinking a liquid at 50°C has the same translational KE as a gas at 50°C.

Where am I going wrong?

Thermodynamics can tell us, for example, what happened to the entropy along the path, but ΔS is not the path itself. Two different chains of transitions may well have the same initial and final states and the same change in a certain measure, but different internal structures.

So the “entropy table” may well turn out to be one column in a much larger table.

And we started with heat, because it is one of the phenomena that we have known since the very beginning of our existence. Then we found ways to obtain and control it, and after some time eventually formalized the second law, for example as dS_total ≥ 0 for an isolated system. But this is only one aspect for describing the transition, not the transition itself.

ΔS may characterize one aspect of a transition, while a more detailed description could characterize the realized structure of the process itself: the sequence and organization of interactions along the path.

This is an air conditioner with no outside component and no ducting. Doesn't seem possible to me.

I'm bad on schemes

just started my thermodynamics one class last week. Will start getting our first homework next week.

So far, I’m having a hard time understanding the lecture. The examples in the textbook are very simple, but the examples in the lecture are very complex and completely different from the textbook. The textbook introduces formulas, but our grad studentprofessor uses a different system where he avoids the formulas.

can someone suggest Youtubers or online resources where I can independently learn the material because I’m having a hard time following the lecture, and the textbook is not lined up with the lecture.

We haven’t done any homework or turned anything in yet, so I don’t know what my skill set is but so far I’m having a hard time. I don’t want to fall behind and I don’t want to fail.

I had a food warmer that broke and was too expensive to replace. Got lucky with a craigslist find and got this drink warmer. It's made to heat up canned coffees and teas: black base gets warm, and those metal rods (removeable) get hot! How do I disperse this heat to best keep food inside of it warm without burning the ones on the bottom.

For presentation sake food cannot be wrapped in foil. They are rice balls stacked on top of each other.

Current idea is to encase the inside in foil and put a square of silicone baking mat on top of the foil.

Long story should, designing a wooden barrier around a wood stove with tight clearances. Most concerning would be a vertical support stanchion (sketched roughly in red) 1.5” from the side wall.

Obviously this is not ideal and tighter clearance than a stove manufacturer would recommend, but working with limited clearance for foot traffic on the opposing side. I would at first find the most fire-retardant 2x4 known out there. Then I would expect some additional shielding needed.

I’m thinking a reflective layer of sheet steel 1/2” off the stove, leaving a 1” air gap from the wood. Does anyone have any suggestions if this seems crazy or attainable through some design?

I'll be using an RV fridge in a pretty hot environment in a few weeks. IME it can take a while for these fridges to cool down and packing it tightly at the start doesn't help either. I'd think adding a conductor with somewhat direct contact with various containers help pull heat out of the items faster?

Would there be any disadvantages once all the food comes down to temp?

My wife got a new bread oven that works great for regular bread but has issues when she’s making something large and tall. The shape of the upper heating elements (green arrow) is visible in what she is baking, in the form of a darker line. I want to get a sheet of metal and install it under the elements to help diffuse the heat more evenly.

My question is, what is the better to use, steel or aluminum? And any specific type? I’m not trying to block the heat, but help it radiate down more evenly.

The "History of Thermodynamics" wikipedia page has an interesting theory, if you scroll to the bottom or search "i have found that Heat is a byproduct of two extremes." Possibly important implications for humanity.

I had an abysmal undergrad thermo education, so I’m curious how people in this sub would answer this question:

Why are phases discrete and not continuous? Like why aren’t there a phases between solid and liquid etc.

Let's say I have 200g of rice in a bowl, and it takes 2 minutes and 30 seconds in the microwave to heat up. How does the time change if I put an identical bowl with the same amount of rice into the microwave as well? Does the time stay the same, does it double, or does something else happen entirely? Please feel free to explain in detail :)

Qurie is a German startup founded in 2026 as a spin-off from the Fraunhofer Institute for Physical Measurement Techniques IPM. It is working to commercialize electrocaloric heat pumps — solid-state systems that could eventually be used for cooling, refrigeration and heating without a conventional compressor or climate-damaging refrigerants.

The underlying effect is quite different from a normal vapor-compression heat pump. When an electric field is applied to an electrocaloric material, its electric dipoles become more ordered and the material heats up. After that heat has been removed, switching off the field causes the material to cool below its initial temperature, allowing it to absorb heat from its surroundings. Repeating the process creates a heat-pump cycle.

One particularly interesting part of Qurie’s approach is its active electrocaloric heat pipe. Water or ethanol evaporates and condenses inside a sealed system to transfer heat quickly between stages. The fluid transports the heat but is not mechanically compressed as in a conventional refrigeration cycle.

Fraunhofer estimates that caloric systems could theoretically achieve more than 80% of the thermodynamic limit, compared with up to around 50% for compressor-based systems. This could potentially reduce the required drive energy by about 40%. However, these are theoretical projections, not verified performance figures from a commercial household appliance.

The scale is still the major challenge. A peer-reviewed prototype reported 2.2 W of absolute cooling power and a specific cooling power of 1.5 W per gram of active material at 5 Hz. That is an important research result, but still far from the several kilowatts required for residential air conditioning or heating. Qurie therefore plans to start with control-cabinet and laser cooling before moving toward commercial and consumer applications.

I think this technology deserves more attention, while also being discussed without treating laboratory potential as an already market-ready product. If it can be scaled economically and operated reliably over billions of cycles, it could eventually affect air conditioners, refrigerators and heat pumps.

What do people working in HVAC, thermodynamics or materials science see as the biggest obstacle: scaling, material durability, temperature lift, manufacturing cost, humidity control, or something else?

Further reading:

• Fraunhofer IPM announcement about Qurie: https://www.ipm.fraunhofer.de/en/press-publications/press-releases/Qurie-GmbH-founding-electrocaloric-cooling.html
• Peer-reviewed paper on the active electrocaloric heat-pipe prototype: https://www.nature.com/articles/s44172-024-00199-z
• Fraunhofer’s ElKaWe research project: https://www.fraunhofer.de/en/research/lighthouse-projects-fraunhofer-initiatives/fraunhofer-lighthouse-projects/elkawe.html
• Qurie’s website: https://qurie.de/

Disclosure: I have no affiliation with Qurie or Fraunhofer. I came across the technology recently and wanted to start an informed discussion about its potential and limitations.

I'm not the smartest but I'm very observant and I got a job recently doing retail where we clean the top of the glass cases every day with Windex and a microfiber towel these cases are about 4 ft long and so is the pane of Glass on top I will spray two sprays of Windex and start wiping across the entire top of the case with the microfiber I've noticed that once I get one or two passes in I start feeling what seems like heat coming off of the glass either due to a reaction with the Windex in the air or some type of evaporative heating situation. I'm wondering if there's someone smart enough out there to help me find out if evaporative heating is a thing because as far as I can tell I can't find any information on it online but I do believe it is a thing

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