Talk:Coulter principle

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This article has several factual errors and states an origin for Wallace Coulter's invention my 20 years of working with him never elicited. What he did indicate as an origin appears in an article in JALA [8(6):72-81, 2003] that is accessible under "Heritage" at www.coultercounter.com.

Mdgraham 19:23, 24 April 2007 (UTC)

The salinity of seawater (about 3.5 percent) does not particularly approximate that of blood (about 0.9 percent). Peter (talk) 03:37, 10 February 2009 (UTC)


The demonstration of the Coulter Principle requires an experiment where there are two different currents.

One current is the flow of sea water measured in mililiters per second between one chamber and the other through the hole. We should notice that this current of water may conduct also electricity because sea water includes several ions dissolved.

The other current in the experiment is the current of electrons measured in miliamperes that flows between the two poles of the electrical battery passing through the aperture in the membrane.

The flow of the water current and the flow of electron current need not be in the same direction and this is in principle irrelevant to the subject because the speed of the electrons would be close to the speed of light while the speed of the current respond to the mechanics of fluid.

What makes the discovery amazing is that all particles that do not allow the pass of electricity will take the space of ions that would transport electricity. That instantaneous removal of ions from the aperture provokes the variation in resistance of the section. 88.207.146.72 (talk) 18:47, 16 March 2009 (UTC)Laertes Boechat boechat@pt.lu88.207.146.72 (talk) 18:47, 16 March 2009 (UTC)


The earlier version was clearly biased, so I have shortened the article significantly, removed all the superfluous biographic data and condensed it so that it only contains the main point. It is now ready to be expanded with informative content. I have also removed the NPOV warning, but if someone want to put it back, I won't object.BroodKiller (talk) 08:24, 7 July 2010 (UTC)

I clarified the point that with the Coulter principle you are measuring the VOLUME and not the SIZE of a particle/cell flowing through the orifice. "Size" is a very ambiguous quantity anyhow and should not be used. It is ambiguous because you could mean the size of a cube, a pyramid or a sphere. Even cells can be elongated and thus any definition of "size" is a poor one with respect to a device using the Coulter principle. Necmon (talk) 09:54, 8 November 2010 (UTC)