The Naked Scientists

The Naked Scientists Forum

Author Topic: How do you get the stripes in toothpaste?  (Read 17084 times)

Offline thedoc

  • Forum Admin
  • Administrator
  • Sr. Member
  • *****
  • Posts: 511
  • Thanked: 12 times
    • View Profile
How do you get the stripes in toothpaste?
« on: 28/02/2012 16:46:23 »
Why when you squeeze a tube of toothpaste with the lines of seperate colours do the colours not smudge into each other? They always come out in perfect lines.
Asked by Louise Allen


                                        Visit the webpage for the podcast in which this question is answered.

 

« Last Edit: 28/02/2012 16:46:23 by _system »


 

Offline thedoc

  • Forum Admin
  • Administrator
  • Sr. Member
  • *****
  • Posts: 511
  • Thanked: 12 times
    • View Profile
How do you get the stripes in toothpaste?
« Reply #1 on: 28/02/2012 16:46:23 »
We answered this question on the show...



Dave -   Essentially, itís by clever engineering.  If you look carefully at the toothpaste, instead of making those beautiful swooshes of toothpaste which they always show on adverts, if you chop the toothpaste straight across, you'll see that the colours are only just on the surface.  In the middle, itís all just normal white toothpaste.  So, what they're actually doing is, in the nozzle, very close to nozzle which squirts the toothpaste out, there are other little nozzles attached to bags of colour Ė often several different nozzles attached to bags of colour.  So when you squeeze a tube of toothpaste, it squeezes both the main toothpaste bit and those little bags.  And so, as the main toothpaste comes out, the extra coloured bits get squeezed out on the outside and you end up with a white tube with little coloured bits around the outside.
Chris -   If you don't believe us, cut a tube up and you'll see this marvellous bit of engineering for yourself.  It was patented in America, I think, in the 1960s or the late Ď50s.  They actually introduced that as a major selling point.  I think Signal was one of the first brands to use it in this country.
Dave -   Probably, I think itís based on a similar system for making icing.  So you can get coloured icing outside and the boring white icing inside.
« Last Edit: 28/02/2012 16:46:23 by _system »
 

Offline RajNSF

  • Jr. Member
  • **
  • Posts: 12
    • View Profile
Re: How do you get the stripes in toothpaste?
« Reply #2 on: 04/03/2012 07:05:27 »
Wow guys :0 that's so interesting!!!!!!!!!
 

Offline zxc1233

  • First timers
  • *
  • Posts: 1
    • View Profile
Re: How do you get the stripes in toothpaste?
« Reply #3 on: 07/03/2012 05:16:09 »
vvvvvvvvvvvvvvvvvv
 

The Naked Scientists Forum

Re: How do you get the stripes in toothpaste?
« Reply #3 on: 07/03/2012 05:16:09 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums