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Problems With Viscosity and the Moon

Problems With Viscosity and the Moon
At an English shampoo factory near the sea, they were having problems with the shampoo viscosity. What was the cause?
Mysteries of Science


This story comes to us from a transplanted English chemist who had more than a bad hair day one night. The scene is a modern shampoo establishment along the coast in Northern England.

Shampoo is formulated, manufactured, tested and packaged in this compact factory near the sea. The shampoo is mixed in a large stainless steel tank and then fed to a bottling line that automatically fills labeled containers.

There really isn't much to making shampoo. There are several quality control steps to insure that a good product is delivered, but not much more technology than a modest instrument lab. Color is important, but the most critical property is viscosity. High viscosity materials, like molasses, flow very slowly and low ones, like water, flow easily.

The shampoos made here have a medium viscosity. A few are thicker gels that go into plastic tubes, but most are put up into bottles. These shampoos are mostly water, and so a thickening agent is added to raise the viscosity.

  We now enter the small quality control lab. The quality control department has been doing routine testing. On this particular night, the product went off scale and they had to put a hold on a bottling operation. The batch on hold was too thick and adding more water didn't help. If too much thickener was added it would be a problem because compensating by adding more water would make the product quite inferior.

On the next evening the batch was off spec again with too high a viscosity reading.

The third night, the same thing happened, but the thick shampoo problem wasn't quite so bad. The product could be bottled. On the fourth night, the viscosity was still a little high, but just within spec. Was something going on - maybe inferior ingredients had been delivered? None of the tests led anywhere and since the problem had finally gone away, the interest waned.

Two weeks later, the problem was back. The shampoo was too thick, and nothing could fix it. If the previous trend repeated itself, there would be trouble again in 24 hours. Like clockwork, the viscosity was too high on the following evening. There was nothing wrong with the mix since both the daytime and night supervisors watched over the situation closely.

Everyone was speculating on the cause when the newly arrived CEO blurted out, "It must be the full moon". Indeed there was a full moon, but it was certainly not a likely cause. None-the-less, "full moon" was added to the list of possible causes since it was suggested as a possibility, even if it was a joke to lighten the tension.

Testing went on through the night and a clue emerged. There was a higher than normal chloride level in the shampoo. Chloride is always present, so not much thought was given to this clue.

The next morning, the day shift QC supervisor, who was also an amateur astronomer, proposed they check the viscosity log against the moon chart. There it was! Viscosity went up to the highest point when the moon was full or when there was new moon. The viscosity changes were tied to the moon, and therefore, the ocean tide cycles. How could the moon and tides affect the shampoo?

It appeared that the shampoo problem was occurring for those few days and nights corresponding with the extra-high tides. The records of off-spec shampoo and spring tides matched perfectly.

How could it all be connected? What about the high chlorine level?

Here's the rest of the story.

Chlorine is from salt like in salt water. The moon and sun are raising the ocean water to the highest point and introducing salt into the shampoo. All we need to do is find a connection between ocean and factory water.

The water supply was checked. The factory water was supplied by wells and they were being periodically contaminated by ocean water. The high tides were seeping into the ground water and adding salt to the factory well water. The fix was simple. They added a water purifier.

The principle that we can glean from this Full Moon episode is never rule out an idea, no matter how far fetched, until the facts eliminate it. The proper axiom comes from England's most famous detective, Sherlock Holmes. "When you have excluded the impossible, whatever remains, however improbable, must be the truth".


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