Many a cave is filled with what look like giant stone icicles. Some of these "icicles" hang down from the cave's roof. Others stick up from the floor. They are often as thick as tree trunks....
Holes in rock
A den for bears and a bedroom for bats. A home for prehistoric people. A dark place of gloom and mystery. A sparkling wonderland of strangely shaped rocks. That's a cave! A cave is simply a hole in...
Layer cakes of rock
The upper part of the earth's rocky crust is like a layer cake. It is made up of many layers of different kinds of rock, one on top of the other. These layers were built up slowly, one after the...
Pictures in stone
Tucked away in the earth's rocks there are often "pictures" from the past. Many times, in ages past, animals walked through mud and left footprints. Slowly, over thousands of years, the mud hardened...
Bones in rock
A giant dinosaur, with jaws shaped like the bill of a duck, plodded along the shore of a lake in search of food. Sighting large horsetail plants growing in shallow water, it waded out toward them. ...
The “magic” metal
aluminum ore (bauxite) Have you ever watched someone wrap a sandwich or cover a bowl of food with what looks like a sheet of shining, silver paper? It isn't paper at all---it's a thin sheet of...
A rock we eat!
> table salt (halite crystals), magnified If someone at the dinner table said, "Pass the rocks, please," what would you give that person? Salt, of course! The salt that people use to season food...
Black gold
The oil that keeps your bicycle from squeaking and the gasoline that keeps your parents' car running both come from deep in the earth's crust. Both began as a thick black liquid found in big pools...
Buried sunshine
Nearly all rocks are made of minerals---things that are not alive and never have been. But there is one kind of rock that is not made of minerals. It is coal, a black shiny rock made of---green...
A slippery mineral
What is inside the pencil you use to write? It's often called "lead"---but it's not really lead at all. It's a mixture of clay and a soft, black mineral called graphite (GRAF yt). Some graphite is...