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Heat transfer by convection
Technically not by convection because that is the movement of fluid to transfer heat in and out of something, like air conditioning. The bath is not a moving fluid it is a simple constant temperature. The spinning moves the fluid inside the can so more of it touches the aluminum wall, which is being cooled by conduction with the ice bath.
Probably to disrupt the temperature gradient that forms around the can. That’s why we blow air on though the top of a hot drink to cool it faster.
cause it looks cooler
I assume so the liquid moves around and gets cooled evenly. If you didn’t move the drink, the outer layer of liquid would get cold, but the inside would take longer to get cold as well
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:
Put a heat sink into your scrambled eggs
I always did enjoy a high protein, high copper diet
Yup. It’s called a refrigerator
“Syfy”
Cyfi
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!
Came here to mention laser cooling; glad someone else got there first.
peltier cooler
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Laser cooling exists, but I don’t suppose you can afford one or want your beer on 2°K
How does that work?? Genuinely curious.
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
Here is an alternative Piped link(s):
great video by Physics Girl and Veritasium
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I’m open-source, check me out at GitHub.
Great bot! But please see the edit to my post
Thank you!! This was a fantastic explanation! Great ELI5 style, I feel I don’t even need to watch that video - even though Veritasium is amazing.
Basicly photons are shot against an atom to slow it down (the slower the elements move the “colder” something gets)
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)
The simple answer is entropy. It’s much easier to poor a bunch of energy into something and have it express itself as heat than it is to retrieve spent energy out of an object. You can burn down a forest and make a lot of light and heat, but you can’t spend light and heat to turn smoke into a dark, cold forest.
We cant do it now thats true. But isnt the process you described called photosynthesis? Using Sunlight (heat in form of UV Waves) to turn Smoke (CO2 and bunch of other stuff that isnt used) with Water into sugars which build the structure of plants?
Given how much about science we still have to learn, I would say it is a distinct possibility. If you want something cheap and easy to use like a microwave to do this though, I highly doubt we’d see that possible for the next 30-40 years at minimum.
What I would like to know is if we will ever have microwaves that stop the spinning plate in the same place that they started. It’s XXI century, I want to take out my cup as easily as I’ve put it in.
It could easily be done, but would only work if: you don’t stop the cycle manually by opening the door, or you are ok with the microwave quickly spinning your food (or liquid filled cup) to the starting position as soon as you do open the door.
No, what it should do is:
- when timer ends or stop button is pressed it should turn off microwaves but keep spinning until original position
- when door is opened just stop everything immediately
This way you can stop the plate manually at any position but when operating microwave in the usual way you get the benefit of the cup always pointing the right way.
It would require variable speed motors and more complex chip and programming so it would be more expensive. Just spinning the plate at the same speed until it makes a full turn could be solved mechanically.
Have it calculate the amount of full rotations and round it down to the nearest whole number. Worst case scenario, your cup is static for 5–10 seconds before the microwave stops.
That can be done, just takes a more expensive Platten motor, and some more code in the control unit.
MostMany microwave plate motors are 6 rpm. If you always stick to 10 seconds increments, it should end right where it started.Most microwaves I use (at home and work) have 30sec increment buttons so I always stick to 10 second increments and no, they don’t end when they started.
Still issue? Idk 😂
Edit: I do see some that use 3rpm so those would always be backwards at 30 seconds. 50hz supply would also change the rotation speed. My turntable is very predictable at least, so i guess I’ll take the personal win and go.
It’s a pretty specific patent that says you delay the cooking by couple of seconds while spinning the plate to ‘synchronize’ the start and stop positions. There are more ways to do it so it would be fairly easy to avoid this patent. I don’t know why it’s not a standard feature.
The reverse microwave. I heard you need a LOT of freon.
Falcoooone
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.
You would need to find a way to make food spontaneously emit microwaves so it loses energy and cools off. That probably involves altering the strength of one of the nuclear forces or something.
That’s an air conditioner. Or a fridge.
You just need to adjust the output and input sizes. Do to like… physics. It is easier to add heat to a system than to remove it.
To be fair, those are more akin to an oven. As they use convection to cool.
Good point.
https://youtu.be/MHm3fHVZitI?si=mkUIGlaqUUt2NPKs
Furze did it… kinda
