The problem is that cold is merely the absence of heat, you can’t inject cold into something or generate cold, because there is no such thing as cold. It’s kind of like how we can make a light bulb, but we can’t make a dark bulb.
Maybe we could start manufacturing mini black holes to build the dark bulbs!
Nope that’s unfortunately not how black holes work. It would essentially look the same as having the bulb painted black.
deleted by creator
Sadly, a mini black hole would suck up everything around it. Much like a tiny Katamari Damacy, it would quite quickly consume everyone and everything around it. Of course after not too long it would become a regular sized black hole.
Some mini black holes do not grow into black holes. They collapse. The issue is that they aren’t stable for any decent length of time. Fractions of a nanosecond.
A capitalist haven, think of how many black holes one could sell!
That’s the best explanation I have seen for heat.
I’ve ran equations for heat so I get it more than most, but always found it difficult to explain.
We have that, it’s called a fridge, and then there’s a freezer for making things frozen.
But a fridge is the opposite of an oven. Some kind of flash freezing would be like the unmicrowave.
The reason we shrink heating devices down but not cooling devices is a combined consequence of economics and the laws of thermodynamics.
First an analogy: Making a boat that moves downstream a river is easy. Take any buoyant material like a log or a branch and drop it in water. Presto, you’ve got a mode of transportation of any size. Want to go upstream? Now you need motors to fight the current. Putting a motor on a large piece of wood, (a boat) is economically viable. Putting one on thousands of sticks? Ain’t nobody got time for that.
As a consequence of the laws of thermodynamics, the the universe naturally converts all potential energy (fuel, electricity) into heat. The universe will do this basically on its own, over time, constantly. This is called entropy.
Doing the reverse, taking heat and putting it back into potential energy, i.e. cooling, is difficult. You basically have to pay a price to the universe in some other way, kind of like how a motorboat has to push more water downstream than the current would have naturally moved on it’s own. This is what heat pumps (AC, fridge) do. Heat pumps put some of that heat back into potential energy, in exchange for also releasing potential energy into heat… The trick here is to do these two things in different places. The fridge’s motor converts some electrical energy into heat in exchange for being able to move some of the heat in the fridge outside of the fridge. The consequence of this is that the room the fridge is in is now hotter. Mostly because you took the heat in the fridge and moved it into the room, but also because the fridge’s motor also added some MORE heat to the room in the process in order to fight entropy. So to actually make this useful, you need to insulate what you are cooling (or it will just get warm again, warmer than it was before, because you added heat to the room), and you also want to dispose of the heat in the room. So you pump that out into the atmosphere…
Anyway, long story short, you need insulation, refrigerant, motors, heat changers, lots of power to fight the universe’s tendency to spread heat everywhere. Technically you could miniaturize these things, but they become less efficient as you shrink them down, to the point where things smaller than a fridge are just not practical to make compared to the benefit you get from having them.
Making small heating devices is easy. You don’t need to fight the universe. You just need an apparatus that will “go with the flow”.
Wow! Thanks for that.
There are blast chillers that are closer to a microwave
Air Frozer
They meant quickly. A fridge nor a freezer can make things cold or frozen in a minute or two.
Those devices are very slow at transferring heat, unlike the microwave.
Yup. It’s called a refrigerator
Refrigeration Tech here. See: Traulson Blast Chiller. I imagine there’d be a consumer version if enough people wanted them.
But isn’t the cooling method an airflow and steady temperature decrease of the chamber?
Seems more like a reverse convection oven than a microwave.
But thanks otherwise. I never knew these existed. Was an interesting read.
Without breaking the laws of thermodynamics, I’m not sure how you’d accomplish that. Being you can’t “make” something cold. You can only remove the heat…
Blast Chillers can make 160°F Poultry 34°F quite fast. Mind you that’s internal Temps. As far as I know, airflow is the best, maybe only way to carry the heat away…
I got that. It was more about how the Blast Chiller generally functions. It does not use radiation from the electromagnetic spectrum like a microwave, but uses airflow like the afromentioned convection oven. But thanks again for explaining. I appreciate the additional input.
Temperature is average kinetic energy. It is very easy to put kinetic energy into an object and much harder to take it out. Microwaves do it by shining a “light” tuned to microwave frequencies on objects. So you can imagine the problem is about as hard as shining a lamp on something and having it get colder. Laser-based cooling methods do exist but they’re quite expensive and mostly operate on the atomic scale. For now, the best way we know of to cool large items in bulk is to put them next to something that’s even colder—in short, a refrigerator.
Laser cooling exists, but I don’t suppose you can afford one or want your beer on 2°K
it also helps to be cooling a single atom at a time
My god where does it end with you beer snobs??
A lot of laser coolers were built exactly for cooling single atoms (to do scientific research)
How does that work?? Genuinely curious.
Basicly photons are shot against an atom to slow it down (the slower the elements move the “colder” something gets)
It’s unintuitive, but super cool! There’s a great video by Physics Girl and Veritasium that explain it better than I ever could here.
First, the wavelength of the laser (think of it as the “color” of the laser) is chosen such that the energy of the photons is just under the energy state of the atoms that you are trying to cool.
Now, when the atom is moving toward the source of the laser, this causes the atom to “see” a higher energy. This is called Doppler shift and is a very well-known effect in anything that emits waves and is moving. In fact, you’ve experienced it before when you hear a car horn – as it moves towards you it has a higher pitch and as it moves away from you it has a lower pitch.
So, for atoms moving toward the source the see the energy rise just enough to absorb the photon and move to a higher energy state. Inevitably, the atom will want to move to a lower energy state (as all matter does) and will end up ejecting a new photon in a random direction. In order to maintain the conservation of momentum, this means that the photon will likely be ejected in a way that counteracts the direction it was previously moving, effectively slowing it down. Since heat is a measure of how fast atoms are moving, this means that atom has cooled down.
For atoms moving away from the laser source, they are unable to absorb the photons because the Doppler shift acts in the opposite direction, and they are completely unable to absorb the photons.
So as a result of all this, it is possible to slow down atoms moving in a very specific direction, without affecting the other atoms. This means you can systematically slow atoms down which means you can systematically cool things down.
Edit: Here’s a piped link to the youtube video above in case you’re privacy-conscious, however, Dianna (aka Physics Girl) has been bed-ridden with Long COVID for a while now so it would be great if you could contribute to her Patreon in lieu of the ad revenue
There are actually two ways to do this. One is a heat pump (like a small ac or an electric cooling plate) the issue is that it would heat up on the other side, so not great.
The other option is actually really interesting as just like a microwave it uses radio waves (in this case lasers) to cool things by shooting the atoms in a way that negates their current movment and slows them down.
Oh, so that’s why when I shot someone they got cold! Silly me. I’m a reverse microwave, not a murderer duh
- the victim was having a fever, your honor!
peltier cooler
Came here to mention laser cooling; glad someone else got there first.
In reductively simple terms heat is really easy to generate. In fact pretty much everything we do creates extra heat entirely on accident, so a device than make things hot on purpose is actually surprisingly simple. It’s much harder to get rid of. The only economical way we’ve found of managing it is by using to phase change of refrigerants to pump it out of enclosed spaces, which is how refrigerators and air conditioners currently work. Everything else would be more complex, less efficient, or both. So if such a thing is even possible it would almost certainly be much more expensive
There’s commercial equipment called blast chillers but it still takes like 10-15 minutes
Part of the problem is if you want to chill something, like a warm beer or bottle of wine, you dont want to freeze any part of it. Sure you could dubk it in superchilled liquid nitrogen at -255 or whatever, but the heat energy leaves the object from the outside, and the liquid nearer the edge would freeze before you got the middle cold. You might also thermally shock the glass and break it.
The fastest way to chill a wine or beer would probably to put it in an immersion bath fully submerged in a dense, thermally conductive liquid like salt water, kept at a temperature of -2 degrees C or so, and a pump to circulate it around, like a cold sous-vide where maximum surfacearea is being exposed to the chilling liquid. If you left it in long enought it might eventually freeze, but you could optimise immersion time and bottle temperature to ensure that its inner heat energy and thermal transfer rate is enough to prevent the liquid at the outer edge from freezig.
If your wine or beer had a magnetic stir bar or something inside to keep the temperature of the inner liquid circulating and thermally consistent, your saltwater bath could go even colder, but that would introduce other problems like nucleating the carbon dioxide in the beer or wine.
There are cheap household gadgets that rotate a can or bottle in a [salt] ice water bath to chill it rapidly. https://www.amazon.com/Chill-Matic-Automatic-Beverage-Chiller/dp/B0148K37K2?th=1 etc
Also more expensive ones with better temperature control for wine bottles.
There is a machine that specifically cools drinks (cans) in seconds. It rolls the can in ice water until it’s cold.
Lemmy sure has gotten popular, bunch of comments that doesn’t understand how microwaves work
Blast freezer. It’s about as close as we’ll get any time soon. Not an affiliate or anything, just googled and found this bugger (about microwave sized).
https://www.nisbets.co.uk/polar-countertop-blast-chiller/ck640
This is technically possible. The cosmic microwave background, i.e. space, is extremely cold (barely above absolute zero) so it basically acts as a heatsink you can pump infinite amounts of heat into. It turns out that if you can make the food radiate heat out into space and prevent it from absorbing more heat from sunlight, it’s possible to cool it below ambient temperature. This is also a completely passive process so it requires no electricity or other form of active energy input.
The problem with this is that doing it with food might be impossible. At the moment, we can only really do it using objects with special coatings that have been optimized for this purpose.
Here’s a couple interesting videos that explain how it works:
Call it Macrowave!
Probably not. Nice choice of pic to illustrate the need, though 😄
