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Author Topic: Why does my magnum wrapper behave strangely?  (Read 1791 times)

Offline thedoc

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Why does my magnum wrapper behave strangely?
« on: 16/09/2015 21:50:01 »
paul davenport asked the Naked Scientists:
   
Can anyone explain to me why, when tearing off the plastic rapper from an Magnum Ice Cream, that one part of the plastic becomes negatively statically charged and the other piece positively charged. The two pieces repel each other.

What do you think?
« Last Edit: 16/09/2015 21:50:01 by _system »


 

Offline PmbPhy

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Re: Why does my magnum wrapper behave strangely?
« Reply #1 on: 16/09/2015 22:15:59 »
paul davenport asked the Naked Scientists:
   
Can anyone explain to me why, when tearing off the plastic rapper from an Magnum Ice Cream, that one part of the plastic becomes negatively statically charged and the other piece positively charged. The two pieces repel each other.

What do you think?
If they repel each other then they must have the same charge. This typically means that electrons moved to or frame another part of the material leaving those parts with an excess or lack of electrons.
 

Offline evan_au

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Re: Why does my magnum wrapper behave strangely?
« Reply #2 on: 16/09/2015 22:29:53 »
Quote from: Paul Davenport
The two pieces repel each other.
A self-opening wrapper! I will have to repeat this experiment (purely in the interests of Science, of course!). Multiple times, just to make sure....

Quote
one part of the plastic becomes negatively statically charged and the other piece positively charged.
PmbPhy beat me by a few seconds, but if the two pieces repel each other, that indicates that they have the same charge, not opposite charges.

It could be that friction with the chocolate of the ice-cream (or your shirt sleeve) gives the two pieces the same charge.
 

Offline jeffreyH

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Re: Why does my magnum wrapper behave strangely?
« Reply #3 on: 17/09/2015 00:29:50 »
Maybe they just don't like each other.
 

Offline evan_au

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Re: Why does my magnum wrapper behave strangely?
« Reply #4 on: 18/09/2015 12:05:21 »
Quote from: paul davenport
when tearing off the plastic rapper
Today I attempted to reproduce this vital piece of research under tightly controlled conditions, and immediately ran into the question of how the wrapper was torn off, so as to result in two pieces that repelled each other.

My natural technique for opening wrappers results in a single piece, which has trouble repelling itself.

However, I did notice that once I opened one flat end of the wrapper, it immediately tended towards a cylindrical form, which could be viewed as the two sides repelling each other. However, I think this is just the slight stiffness of the plastic redistributing the stresses in the most economical way, producing a roughly circular cross-section. 
 

Offline Bill S

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Re: Why does my magnum wrapper behave strangely?
« Reply #5 on: 18/09/2015 15:36:00 »
Hi Paul, thanks for giving me an excuse to eat lots of Magnums.  It might be worth experimenting to see if there is a difference between plain, milk and white chocolate, or between different ice cream flavours.  :D

This could push up the value of Unilever shares.

 

Offline Colin2B

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Re: Why does my magnum wrapper behave strangely?
« Reply #6 on: 19/09/2015 22:37:44 »
It could be that the whole wrapper carries a charge acquired during manufacture.
Do other products - including a wide variety of sweets and biscuits - exhibit this same phenomenon?
Let's keep experimenting until we solve this one.
 

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Re: Why does my magnum wrapper behave strangely?
« Reply #6 on: 19/09/2015 22:37:44 »

 

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