Showing posts with label geology. Show all posts
Showing posts with label geology. Show all posts

January 29 - Happy Birthday, Frederick Mohs

    Posted on January 29, 2022


This is an update of my post published on January 29, 2011:




The German geologist Frederick Mohs is most famous for his Scale of Hardness. 

A geologist is a scientist who studies rocks and minerals and the origin and structure of the earth. So it may not surprise you to learn that Mohs's Scale of Hardness concerns rocks and minerals! 

Talc - 1
Born on this day in 1773, Mohs compared the hardness of various minerals, comparing each to the others by scratching one mineral onto another. Obviously, a harder material can scratch a softer one, but a softer material cannot scratch a harder one. Using his comparative data, Mohs created a scale that goes from one of the softest minerals, talc, at Number 1, to the hardest mineral, diamond, at Number 10. Of course, some minerals fall between the numbers and can be expressed as a decimal. For example, tin is considered 1.5. Also, the hardness of non-minerals can be expressed using the Mohs Scale; fingernails are about 2.5, for example, and glass runs from 5 to 6.

Diamond - 10





Malachite (above) and azurite (below) both
score between 3.5 and 4 on the Mohs Scale.





Amethyst - 7
Check out this short video about the Mohs Scale.  

 


Explore gems and minerals at the Smithsonian website.


The Hope Diamond can be seen at the Smithsonian

 


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September 7 - Happy Birthday, Ferdinand Vandeveer Hayden


Posted on September 7, 2021


This is an update of my post published on September 7, 2010:


Born in 1829, the American geologist Ferdinand Vandeveer Hayden did pioneering surveying expeditions of the Rocky Mountains in the late 19th century.

In other words, he studied the gorgeous, rugged Rockies!


I've taken several trips through the Rockies, and I love the land—the jagged peaks and glacial tors, the lakes and waterfalls and cascading streams, the elk and deer and moose, and especially the rustling aspens among the stately dark pines.



One of my favorite spots on Earth is Yellowstone, and Hayden not only did an early study of it, he helped convince Congress to set aside that land as a National Park.

Yeah, Hayden!






Hayden is acknowledged as having made the first discovery of dinosaur remains in North America. He found some isolated teeth during an exploration of the upper Missouri River. I don't know if he actually identified the teeth as belonging to dinosaurs. Later, many dinosaur skeletons were found in the West, and a couple of Great Dinosaur Rushes occurred as paleontologists rushed to be the best or to find the most.

But Hayden was first.



Celebrate Hayden!




  • Geysers are rare in the world—but not at Yellowstone! More than half of the entire world's geysers are in that one national park!


 
Learn about geysers using Alka-Seltzer and liquid soap or Diet Coke and Mentos.

 


 
(It's important to use Diet Coke, because the regular stuff is really sticky. Actually, it's important to do geyser experiments outside in a place that doesn't mind a gushing mess!)

  • It's fun to check out where different dinosaur fossils have been found. But remember that dinosaurs-in-general lived for about 165 MILLION years - more than 800 times longer than humans have been around!



  • Here is a gallery with illustrations of many different types of dinosaurs. Explore!

 






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