Sit. Rep. #14: MnO2

1- Obsidian is a “glass” rock formed in volcanoes from the viscous lava. It is mostly silica. Silicon dioxide ( SiO2 ) is a chemical compound that is also known as silica. Not only is silica abundant in the earth’s crust, but it is also present inside our bodies in considerable amounts. Silica is needed for the healthy maintenance of bones, cartilages, nails, tendons, teeth, skin, blood vessels, etc. It is naturally present in water, carrots, bread, cornflakes, white rice, bananas, raisins, etc.
Also, silica is widely used in ceramic, glass, and cement industries.

1B- The ancient Roman historian, Pliny, suggested that Phoenician merchants had made glass in the region of Syria around 5000 BC.  But, the archaeological evidence shows us that the first man-made glass was in Eastern Mesopotamia and in Egypt around 3500 BC.  
     Around 1,000 AD, the city of Alexandria, Egypt was the glass manufacturing center. And the glass was being made throughout Europe. The colored glass was mostly used in the cathedral windows artwork (Stained Glass). To make glass you have to heat sand to 3,100 F to melt it. That is 1,700 C. Really, Really, Really hot. (Note: There have been discovered techniques to lower the melting point of sand.) I saw glass being blown in Williamsburg, VA.
In 1291 AD all of the Italian Glass Manufacturing was transferred to the island of Murano. (Because so much heat was required, the glass-making folks kept setting buildings on fire – so the government moved them to an island where the damage could be contained.)
During the 15th-century Venetian glass blower, Angelo Barovier, crated cristallo, nearly colorless, transparent glass. He added Manganese Dioxide ( MnO2 ) to the sand so the product glass was transparent.

2- Then the glass either had to be molded, ground, or blown just right to make lenses. The first glass lenses were used as glasses to aid people with poor eyesight.
3- Enter Galileo Galilei. He put multiple lenses to work. He built a telescope to look at the stars. Putting 2 or more lenses together is called compound lenses.
4- While Galileo was looking up, some folks were looking down and invented the microscope. Two new sciences were born based on the invention of clear glass.

A- What is the Dentist’s favorite time of day?
B- Tooth thirty.

5- Please touch base with your Scoutmaster update him/her on your Scouting progress.

C- Why did the student eat the homework?
D– The teacher said it was a piece of cake.

Stay safe,

Scout Jokes by Thomas Mercaldo

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.