Sedimentary Rocks

Continuing along in our Rocks & Minerals study, we learned about Sedimentary Rocks. 

First we did a demonstration to show the difference between sedimentary and metamorphic rocks, and to show how the same minerals put together in different ways can form into different rocks.

First, I made two piles of crayon shavings in two very different colors.  This was actually the hardest part since I evidently don’t have a crayon sharpener and my pencil sharpener kept getting clogged.

 

We put a little of each color on to small pieces of foil and wrapped them into little packets….

then we squished one of them (by having Vicki jump on an old baking sheet laid on top of the packet)

the other packet I heated for a few seconds over the stove and let it cool.  We unwrapped and examined our two new “rocks”.   The one that only had pressure applied had the same starting and ending colors, the texture was still rough with some larger pieces visible.   The one that had heat applied had some yellow and red chunks still but was mostly orange and smooth.  

We then took a close look at the sedimentary rocks from our collection and used the key in REAL Science Odyssey to identify them.

The conglomerate was easiest to identify by it’s visible pebbles held together by material.

  

The sandstone is rough (like sandpaper) and grains can be rubbed off easily.

Our last sedimentary rock, shale, had very tiny grains and had visible layers.

We then made our own sedimentary rock.  My original intention was to have the kids collect things to add to our jar but we had our fourth straight day of rain, so instead I popped outside to gather some materials.  We added some dirt, leaves, pebbles and even a shell to our jar.  We then added Epsom salts and water, screwed the top on and shook it up.  We observed the jar as the various materials settled and discussed how it settled into layers and why.  We poured off the excess water and left it to dry.   I have a feeling it’s going to take a few days before our “rock” is ready.  (This demonstration is from “Geology Rocks”).

We finished up with the kids playing a rock cycle game found at The Learning Zone for the Oxford University Museum of Natural History.

  

I was hoping to finish up our Rock & Minerals study this week but it looks like Metamorphic rocks will need to wait until next week.