Showing posts with label Metal. Show all posts
Showing posts with label Metal. Show all posts

Thursday, March 21, 2013

What does the inside of the earth look like?


Beneath the earth’s rocky crust are the hard mantel, hot liquid outer core, and the solid metal inner core.

Have you ever tried to dig a deep hole—maybe all the way to the other side of the world?  Of course, you could dig only a few feet.  But suppose you could dig a hole straight to the center of the earth.  What would you find on the way?
Earth

First comes the crust, or rocky “skin,” that covers the earth.  This may be about 30 miles thick in some places.  As we go down into this crust, we find that it  begins to get hotter and hotter.  At two miles below the surface of the earth, the temperature is hot enough to boil water.   Next comes a layer of hard, black rock, about 1,800 miles thick.  Inside this layer is the earth’s core.  The core seems to be a kind of super-hot liquid metal.

Scientists think that in the center of this core there lies a ball-shaped inner core of solid metal, which forms the very center of the earth itself.  We have been able to find out about the inside of the earth by studying earthquakes.  Probably we will never get to look at the earth’s core, but someday we will know more about it.-Dick Rogers

Thursday, December 20, 2012

What is brass made of?


Brass
Brass is a yellowish metal made by melting copper and zinc together.  Brass is hard and strong and holds a bright finish. Many of the metal things we use today are made of brass.

Brass is a long wearing, yellowish-colored metal that is used in making such familiar things as brass doorknobs, pins and brass musical instruments.  It has a great many other important uses as well.

But no one has ever heard of brass mines.  That’s because there are not any.  Brass is not a single metal, as is gold or iron.  It is a mixture of two metals – copper and zinc.  A mixture of this kind is called an alloy.

In making brass, the copper is melted in an electric furnace.  Small pieces of solid zinc are then added to the melted copper.  The zinc dissolves in the motion copper in much the same way salt may be dissolved in water.

When the mixture cools, it hardens into a metal that is much stronger and tougher than pure copper, and therefore resists wear better.  Brass can be polished to a bright finish.-Dick Rogers