[moside]

Hi

As you can see this is my first post and I also have to confess to being a total chemistry novice.

I'm looking for assistance in identifying a chemical compund (if this is the right phrase) that I'm pretty sure I once saw on a TV science show. As far as I can remember the substance came in a liquid form but when it was hit with a sudden impact it would solidify. The demonstration showed the TV presenter slowly putting their finger into the liquid and then demonstrating that if they tried to punch it then it would solidify and absorb the impact.

Does this mean anything to anyone? Even if its only pointing me in the direction of something similar then that would be a huge help. I'm trying to incorporate this chemical compund(?) into a product design and would like a name so I can research it and give the project some validity.

any help is much appreciated

thank you so much

[Bakegaku]

I believe they're called liquid crystal.  They're used in a number of electronic appliances... I hope you're able to derive something from this.

[AWK]

Sodium thiosulfate , when warming) melts in its crystallization water, and easily forms a supercooled liquid.
This liquid,  when shaken, suddenly crystallizes.

[jdurg]

Sodium thiosulfate , when warming) melts in its crystallization water, and easily forms a supercooled liquid.
This liquid,  when shaken, suddenly crystallizes.

I was going to reply with that too, but that isn't what the OP was asking about.    The substance the OP is referring to will act as a solid if it is hit with some force, but will immediately become liquid again when the force is removed.  With sodium thiosulfate, once it crystalizes it doesn't "uncrystalize" on its own.  I've seen the substance the OP is referring to before and I believe that it is a viscous liquid with a very high surface tension which causes the "solid" feeling when you pound on it.  The liquid itself doesn't actually turn into a solid, but the very high surface tension is able to absorb a strong impact.

[moside]

jdurg

that sounds exactly like what i'm thinking about.

i think it was indeed the surface tension that resisted the impact rather than the liquid actually turning solid (sorry for getting this wrong). have you any idea what this substance might be called or where i can perhaps start looking for information on it? I originally saw the demonstration on a UK science show called tomorrow's world but it was a long time ago.

thanks for all your help guys, like i said i'm a total novice and i have wasted many an hour on google trying to find leads on this.

all ideas / leads greatly appreciated

[jdurg]

I think what you are looking for is known as a rheopexic gel.  It's a substance that hardens when subjected to shearing or stresses such as being hit with a hammer or fist.  A similar substance is a sand/water mixture.  If you slowly put your finger in it, you'll go down into the stuff without a problem.  If you try and smack it with your fist, however, it's like punching a brick wall.  

[moside]

jdurg

thanks again. just checked out rheopexic gel on google and it seems like its the stuff i'm on about. unfortunately it seems like alot of other people have thought of similar potential uses for it as myself. still i guess in a way its a positive sign that i'm clearly thinking in the right way, just a shame i'm years too late.

thanks for the help everyone, it was really really appreciated

[moside]

although i have found some information relating to rheopexic gel on google in mainly relates to patents being lodged for its use. do you think it would be worth starting a new post with rheopexic gel as the title to see if i can find out any more about it?

i would go and do this but as i'm new i'm not exactly sure what forum i'm best doing this in, would it just be this one?

thanks

[jdurg]

Go ahead and place it where you think it would fit.  If it is decided later on that it would be better off someplace else we'll just move it.