# “Hot” coffee cup **URL:** \ **Category:** Factual Questions\ **Created:** [January 20, 2024, 7:45pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406 "2024-01-20T19:45:03Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [January 20, 2024, 7:45pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/1 "2024-01-20T19:45:03Z")
In the 1950s, the public narrative by government and industry, “peaceful uses” of atomic power were going to make all of our lives easier. Dredging harbors, nuking the Moon, electricity “too cheap to meter”. None of that happened, but I’m not bitter. Well maybe a little… We tend to call using a microwave oven “nuking” our food, but that isn’t really accurate. I got to thinking, a common use at least for me is re-heating coffee or tea in a cup. What I really need, then, is a coffee cup that doesn’t cool down in the first place. Ever. Is there a suitable isotope that could be incorporated into a cup, say a nice half life of 20+ years, and yet benign enough not to poison the user? It would be most excellent to never make the arduous trek to the microwave again. Alternatively, a Permsnent Thermos would be an acceptable substitute and maybe more technically feasible. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [January 20, 2024, 8:18pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/2 "2024-01-20T20:18:17Z")
Yeti. ---
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [January 20, 2024, 8:19pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/3 "2024-01-20T20:19:33Z")
That doesn’t sound very radioactive ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [January 20, 2024, 8:21pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/4 "2024-01-20T20:21:15Z")
They work. Without the danger of radioactive problems. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [January 20, 2024, 8:22pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/5 "2024-01-20T20:22:26Z")
I know I’m in trouble 😑 ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [January 20, 2024, 8:22pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/6 "2024-01-20T20:22:27Z")
You need something like this, but smaller. > **[Beta-M](https://en.wikipedia.org/wiki/Beta-M)** > > The Beta-M is a radioisotope thermoelectric generator (RTG) that was used in Soviet-era lighthouses and beacons. > The Beta-M contains a core made up of strontium-90, which has a half-life of 28.79 years. The service life of these generators is initially 10 years, and can be extended for another 5 to 10 years. The core is also known as radioisotope heat source 90 (RHS-90). In its initial state after manufacture, the generator is capable of generating 10 watts of electricity. The generator contains... ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [January 20, 2024, 8:24pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/7 "2024-01-20T20:24:00Z")
> [@Beckdawrek](#): > > They work. Without the danger of radioactive problems. True, though even a well-insulated mug is just going to slow down the cooling, not effectively stop it (which is what the OP is really seeking). It sounds like they would like a mug that can keep a hot beverage at that temperature for an indefinite period, without being toxically radioactive; I’m not sure that such a unicorn exists. ---
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [January 20, 2024, 8:24pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/8 "2024-01-20T20:24:34Z")
If my aunt had balls, she’d be my uncle. I’m just curious if this were technically possible. I realize there are many ways to keep our beverages warm. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 20, 2024, 8:25pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/9 "2024-01-20T20:25:07Z")
On the one hand, it wouldn’t be too hard to find a suitable alpha emitter, and make sure all of the material was thoroughly encased by the ceramic. Alpha particles are stopped by almost anything (giving up their energy to heat in the process), so it wouldn’t directly irradiate you. On the other hand, all those alphas are likely to produce a bunch of secondary radiation, at least some of which is going to be gamma, which will basically ignore a few millimeters of ceramic. And on the gripping hand, you can’t really adjust a source like this to account for different fluid levels. When it’s full of water, heat will escape it much more easily than when it’s empty, and so if it can sustain a full cup of liquid at appropriate temperature, then when it’s dry and just sitting in your cupboard, it’ll get much hotter, possibly dangerously so. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [January 20, 2024, 8:26pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/10 "2024-01-20T20:26:11Z")
I promise you they work. Coffee at temp will still be at temp 8 hours later. I’ve had ice remain ice for a day or more. ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [January 20, 2024, 8:26pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/11 "2024-01-20T20:26:19Z")
> [@Darren\_Garrison](#): > > You need something like this, but smaller. And, I imagine, less likely to cause radiation poisoning if the casing develops a crack: > [@](#): > > In December 2001 a radiological accident occurred when three residents of Lia, [Georgia](https://en.wikipedia.org/wiki/Georgia_(country)) found parts of an abandoned Beta-M in the forest while collecting firewood.[[4]](https://en.wikipedia.org/wiki/Beta-M#cite_note-IEA-4) The three suffered burns and symptoms of [acute radiation syndrome](https://en.wikipedia.org/wiki/Acute_radiation_syndrome) as a result of their exposure to the strontium-90 contained in the Beta-M. ---
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [January 20, 2024, 8:26pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/12 "2024-01-20T20:26:44Z")
Yes! This shows promise. Heathkit really dropped the ball on this, I think. Strontium 90 it is? Would fit right in with the thread on Shop Class projects. ---
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [January 20, 2024, 8:27pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/13 "2024-01-20T20:27:29Z")
It needs to be Dishwasher Safe, definitely. ---
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [January 20, 2024, 8:28pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/14 "2024-01-20T20:28:10Z")
Dude. Give it up. This is a thought exercise. Mental masturbation. Thanks for playing, though. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [January 20, 2024, 8:29pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/15 "2024-01-20T20:29:35Z")
> [@kenobi\_65](#): > > And, I imagine, less likely to cause radiation poisoning if the casing develops a crack: The OP didn’t specify that the solution had to be a sane one. ---
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [January 20, 2024, 8:31pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/16 "2024-01-20T20:31:10Z")
> [@Chronos](#): > > On the other hand, all those alphas are likely to produce a bunch of secondary radiation, at least some of which is going to be gamma, which will basically ignore a few millimeters of ceramic. Lead? I’m confident the technical hurdles can be surmounted! ---
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [January 20, 2024, 8:36pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/17 "2024-01-20T20:36:34Z")
I’m not absolutely wedded to the notion of a decaying radioactive isotope coffee cup, but it seems the best or most lotical solution to this vexing problem. It would be optimal that the product not kill the operator, which presumably would impact sales, or possibly invite a certain level of scrutiny by various meddlesome regulatory agencies. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [January 20, 2024, 8:41pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/18 "2024-01-20T20:41:59Z")
It’s Plutonium-238 you want. Alpha emitter, easy to shield. 87.7 year half life. About a thousand watts IIRC for a kilogram, which is not a big mug as the stuff’s quite dense. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 20, 2024, 8:44pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/19 "2024-01-20T20:44:05Z")
A thousand watts is a lot more than you’d want, anyway. ---
**Author:** ![pjd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pjd/32/3009_2.png) [@pjd](https://boards.straightdope.com/u/pjd)\ **Post date:** [January 20, 2024, 8:48pm UTC](https://boards.straightdope.com/t/hot-coffee-cup/996406/20 "2024-01-20T20:48:04Z")
Surely a tiny microwave device could be built into the bottom of a mug. Maybe USB powered/chargeable. Obviously would need some sort of lid during the heating process. [Next page](https://boards.straightdope.com/t/hot-coffee-cup/996406.md?page=2)