Monday, April 22, 2013

That Which Sparkles

Figure 1

Lately, while taking my dog on one her numerous walks, I have been noticing an increase in the sparkles on the the side of the road and on the lawn near the road.  Notice the center of figure 1. There has always been a few of these tiny shiny fragments but not this much.  Even when I walked her in the dark with my headlamp, the reflection was quite impressive.  My hypothesis is the town has a new source for their winter salt-sand mixture, one that has a high mica content, or more specifically muscovite (the mineral responsible for the sparkles).  Of course to check this I would have to contact the town and they might think I am nutcase and also who has the time for that.

Muscovite, (KAl2(AlSi3O10)(F,OH)2) is a soft, platey, silicate mineral common in granitic type rocks.  Flat, sheet, or platy silicate minerals are classified as phyllosilicates.  Muscovite is colorless but can be lightly shaded green, brown, yellow, or even red unlike the other main mica, biotite (K(Mg,Fe)3AlSi3O10(F,OH)2), which is dark or black. Notice Figure 2 on my son's hand.
Figure 2
If you are still interested in muscovite you might be a closet geologist and I recommend reading a mineralogy textbook.  One last thing, the name muscovite comes from the use of the mineral for glass in Russia.
Figure 3

Monday, April 1, 2013

Phlogiston is Finally Put to Rest by Lavoisier

APRIL 2013
Antoine Lavoisier was a French chemist (1743-1494) who became known as “The Father of Modern Chemistry” with good reason.  He named  oxygen and hydrogen, predicted silicon, helped construct the metric system, and discovered that sulfur was an element rather than a compound to name a few of his achievements.  In one of his more famous experiments, he burnt phosphorus and sulfur in air, and showed that the products although they weighed more than the original, the weight gained was lost from the air, thus establishing the Law of Conservation of Mass.

What about the Phlogiston theory which postulated that materials released a substance called phlogiston when they burned first described in 1667?  The theory was an attempt to explain combustion and rusting and was accepted by most of the scientists of the time.  However, Lavoisier demonstrated the correct role of oxygen in the rusting process as well in respiration. Along with Pierre-Simon Laplace, Lavoisier conducted experiments that showed that respiration was essentially a slow combustion of organic material using inhaled oxygen.  In other words, he disproved the release of phlogiston.

At the age of 28, Lavoisier married 13-year-old Marie-Anne Pierrette Paulze who translated from English to French for him and illustrated his books.  Unfortunately for Lavoisier he was essentially a tax collector for the king during the French Revolution and was tried, convicted, and guillotined on 8 May in Paris, at the age of 50.    

ScienceWorld: Lavoisier