Hypothetical material that converts kenetic energy into heat?

[ForeverNoobie]

I hope this is the right section.

 

So I'm working on a science fiction story where people crash land on an alien planet. The first thing they need is a heat source but none of the plants on that planet are flammable. I thought it would be cool if they found a type of rock that gets really hot if you strike it with something hard. Is such a material scientifically feasible? If so how could I explain that in science terms?

 

Can anyone come up with a better heat source?

[DrP]

Some materials change their chemical orientation and crystal structure during an impact.... some Ti containing ceramics for example. I do not know of any that produce heat (although, being pedantic, the act of hitting a rock will heat it slightly)... If it is just si-fi you are after then I think it is feasible that the crystal structure of these alien rocks could re-arrange exothermically through impact. The energy from the impact could start the reaction/phase change or crystal reorientation and heat could be produced.... although if it is fiction then you can make up anything. ;-)

The impact in the ceramic I was thinking of imparts enough energy in the system to overcome the energy of binding (or whatever it's called) and the structure rearranges... the result is a ceramic ball that can be hit over and over with a hammer and it does not break (until all of the structure has re-arranged and then it becomes brittle and finally shatters).

[swansont]

If it's just a direct conversion of work, the it's like a spring heating up as you flex it. That's not very useful.

 

I think if you take DrP's suggestion and describe it as being in a metastable state, it might be plausible. Some kind of volcanic rock that has a structure when it cools rapidly but relaxes to a lower-energy state if sufficiently perturbed. You could even have evidence of this in the form of rocks that have fallen down a hill and have the other structure where it was struck, or they see it happening.

[Strange]

You could even have evidence of this in the form of rocks that have fallen down a hill and have the other structure where it was struck, or they see it happening.

 

If it is sufficiently energetic, this could initially be presented as a danger to them, until they realise that they can harness it.

[John Cuthber]

Coal, with pyrites in it.

[DrP]

What Swans' said about them being in a 'metastable state' - that's exactly what I was thinking and what I was trying to get across.

 

I like the idea of a land slide of exploding rocks... lol. As Strange suggested this could kill one of them off and they can then scan the rocks and realise that they can harness this property if they impact the rocks on a smaller scale.

 

Good luck with your book!

[Klaynos]

I think the metastable state sounds the most realistic. Especial as there are similar things people will have interacted with (phase change hand warmers).

[swansont]

What Swans' said about them being in a 'metastable state' - that's exactly what I was thinking and what I was trying to get across.

 

I like the idea of a land slide of exploding rocks... lol. As Strange suggested this could kill one of them off and they can then scan the rocks and realise that they can harness this property if they impact the rocks on a smaller scale.

 

Good luck with your book!

They wouldn't have to explode, just heat up.

[John Cuthber]

Last time I checked, coal, in air, was metastable.