# Is this possible? Any thermodynamics dynamos out there want to weigh in?

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I'm an installation artist who works with social interactive concepts which point at how we affect each other, even if we never directly encounter each other. I'm working on a new piece and I have some questions about heat.

I am looking for a material which a person might lie on. If they were to lie still, the warmth of their body would be imprinted for a time onto this material, and if someone else were to touch the material, even, say, ten minutes after they left, the new person would be able to feel the warmth of the other's departed body with their hand. Perhaps sharply so. Were that new person to lay on this material, they would feel warm for a time, until the material had normalized to the new body.

I was originally thinking of basalt stone in the sun, and how it holds and ratiates heat for hours after the sun has passed.

Anyone have any ideas?

Grateful for all input.

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24 minutes ago, K8H said:

I am looking for a material which a person might lie on. If they were to lie still, the warmth of their body would be imprinted for a time onto this material, and if someone else were to touch the material, even, say, ten minutes after they left, the new person would be able to feel the warmth of the other's departed body with their hand. Perhaps sharply so. Were that new person to lay on this material, they would feel warm for a time, until the material had normalized to the new body.

If one person with a skin temp of 95F lies on the material to warm it up, and ten minutes later another person with a skin temp of 95F touches it with their hand, the second person is going to feel less than or equal to 95F, so it will feel either cooler or the same, but not warmer. Does that make sense? Like when you test someone for a fever by touching their forehead, you feel the difference between 95F and 100F as warmth.

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Reminds me of the fagging scene in the 1960s film “If”:

“Oh, and warm a lavatory seat for me - I’ll be be down in five minutes.”

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Anything with a high heat capacity will retain a higher temperature for a while. It will also take longer to warm up.

Basalt is 0.84 kJ/kg-K (0.84 kilojoules required to raise 1 kg by 1 K, or 1 degree C)

Wax and beeswax are significantly higher

How warm something feels to the touch depends on how well it conducts heat. Room-temperature metal feels cool because it conducts heat well.

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• 4 weeks later...

Thank you so much for these answers! I'm sorry I was unable for some reason to reply to anyone. Of course, these things make sense. Now what I'm wondering is... here's the result I want to have happen. Can any of you think of a way that it might work?

Picture a smooth stone block. A person lays on it. When they get up to leave, the stone is warmer than their body was, leaving a distinct thermal field another body can enter. When another body lays on the stone, that person can feel the imprint of the person before them shift into their own imprint. The stone never grows cold.

Thoughts? Infrared mapping of the body to direct external heating (could this be done by warm water flowing under the stone?) If so, could the stone suddenly go very cold as well, almost frosty?

PS. Exchemist - I love a warm seat.  I taught skiing in Japan for many years.

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13 minutes ago, K8H said:

Picture a smooth stone block. A person lays on it. When they get up to leave, the stone is warmer than their body was

You can’t transfer heat to a body at a higher temperature. (a consequence of the second law of thermodynamics) You have to have another, hotter, heat source, or do work on the stone.

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You can of course, detect warmer than expected, even if contacting something cooler than the body.

A recently sat on toilet seat being an example familiar to most.

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