Another day we read about sedimentary rocks in our books and filled in a bit of information in the boxes on the sedimentary rock page, Three Types of Rocks Packet. I brought out our rock collection. We had several different types of sedimentary rocks and the kids had to determine whether they were sandstone, limestone or shale by feeling the rock and grains.
We also filled in the next parts of our rock chart. I got the chart for about $10 a number of years ago. It’s now $16.50. I would recommend it if you have a child who loves rocks (as ours did a number of years ago), but maybe not if you’re using it as a once-off for a unit study.
The chart included gypsum (the packet I made did not), so we had to pull out our gypsum rocks. When we lived in Australia we drove to a remote town in the outback called Coober Pedy. It is known for its opal mining. While we were “noodling” (looking for opal chips) in the public areas, we were fascinated by the gypsum crystals! The kids and I came to the computer and looked at some of our old photos of the gypsum in Coober Pedy, Australia:
Then kids spent quite a bit of time looking at the small pieces of gypsum we still have. They pulled the crystals apart and were really intrigued by it. I don’t know how well you can tell from the photo, but some of the gypsum has a layer of sandstone (or whatever) on top.
Mexico’s Cave of Crystals
The most incredible cave in the world has giant gypsum crystals. Just before we had visited Coober Pedy and saw the fascinating gypsum crystals for ourselves, this piece came out about a 120+F cave in Mexico that has some of the most incredible crystal structures in the world! It is so hot in the cave that the geologists and photographers had to wear ice pack vests when they went exploring. Plus, they had to limit their visits to just 20 minutes. I highly recommend you go look at the incredible video of the scientist’s exploration of the cave: The Giant Crystal Cave Video. You can also look at still photos of the Giant Crystal Cave over at National Geographic.
As I mentioned when I first shared the three types of rocks packet I made, we’ve been singing the Rock Cycle Song (to the tune of “Row, Row, Row Your Boat”). It’s catchy and the kids now know it by heart!
Has been formed in layers
Often found near water sources
With fossils from decayers
Then there’s igneous rock
Here since Earth was born
Molten Lava, cooled and hardened
That’s how it is formed
These two types of rocks
Can also be transformed
With pressure, heat and chemicals
Metamorphic they’ll become
You may be interested in these previous posts related to our rock unit. The first several posts have some free downloads:
I shared some of our hands-on activities in these related posts: