What Makes Silly Putty Bounce and Stretch?

[4nnie]

Homework Statement

Our teacher said we get extra credit for presenting basically how silly putty works and what the origin of its odd properties are. She said there is also some Chemistry in there, but the focus is on the physical aspect. She kept it pretty vague so that we have to find out the relevant things for ourselves.

Homework Equations

I don't think there are any relevant equations for this.

The Attempt at a Solution

So first I wrote down possible questions:
Why do its properties differ from ordinary play doh? Especially: Why does it bounce?
What molecular explanation is there for the viscoelasticity?


The main ingredients are Silicon oil and Boric acid. Normal play doh usually has starch. The are both polymeres.
And they both have viscoelasticity. But I simply cannot figure out what causes the silly putty to bounce, and not the ordinary play doh. At first I thought it had something to do with hydrogen bonds, because they are in there, but they are also in starch, so I don't think they cause the viscoelasticity. Also what does viscoelasticity on a molecular level actually mean? If I apply force, apparently the hydrogen bonds break. But again that goes for the both of them, so what is it that gives the silly putty this unique properties? What do silicon and boric acid basically do that makes the product viscous and elastic? Maybe I am not asking the right questions here? What do you think? Thanks for your help!

 

[haruspex]

I think it's all to do with relaxation time. Try this link http://www.physics.usyd.edu.au/~cross/SILLYPUTTY.htm

 

[Chestermiller]

check out this web site: http://en.wikipedia.org/wiki/Polydimethylsiloxane

 

[berkeman]

Homework Statement

Our teacher said we get extra credit for presenting basically how silly putty works and what the origin of its odd properties are. She said there is also some Chemistry in there, but the focus is on the physical aspect. She kept it pretty vague so that we have to find out the relevant things for ourselves.

Homework Equations

I don't think there are any relevant equations for this.

The Attempt at a Solution

So first I wrote down possible questions:
Why do its properties differ from ordinary play doh? Especially: Why does it bounce?
What molecular explanation is there for the viscoelasticity? The main ingredients are Silicon oil and Boric acid. Normal play doh usually has starch. The are both polymeres.
And they both have viscoelasticity. But I simply cannot figure out what causes the silly putty to bounce, and not the ordinary play doh. At first I thought it had something to do with hydrogen bonds, because they are in there, but they are also in starch, so I don't think they cause the viscoelasticity. Also what does viscoelasticity on a molecular level actually mean? If I apply force, apparently the hydrogen bonds break. But again that goes for the both of them, so what is it that gives the silly putty this unique properties? What do silicon and boric acid basically do that makes the product viscous and elastic? Maybe I am not asking the right questions here? What do you think? Thanks for your help!

Silly Putty has some other unusual properties, in addition to its bouncyness (is that a word?). Can you list some more of them? One comes to mind involving a comic book or newspaper...

 

[berkeman]

Interesting new developments:

https://www.physicsforums.com/showthread.php?t=726416

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