Wednesday, April 29, 2015

Rocks/Crystals: part 3

More on rocks and crystals!  
We have been talking about the different shapes crystals can be.   We looked at close up pictures of salt and sugar, and we looked at the crystals we grew from Borax with magnifying glasses.  

This is a model of a crystal we put together:  (green thing is an eraser)

Levi tried out the "scratch test" on the back of a tile he found in the garage.   He was disappointed to discover his "big chunk of gold" was fools gold!   It had a black streak, not yellow.  

And, lots of fun, he hammered geodes.    I got these at a garage sale a long time ago, but they can be ordered online lots of places too.    We talked about how geodes are formed:   water containing minerals seeps into "bubbles" in rocks,  the water evaporates, leaving crystals behind.   Sometimes the process happens multiple times leaving layers of crystal that can be different colors.  

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