After learning a bit about mixtures, the boys were ready to discover the differences between rocks and minerals. Truthfully, I had completely forgotten what the difference was. Also, despite reading several books on rocks and minerals on our first exploration day and trying to look it up online I was still stumped. Fortunately, the light scripts and demonstrations Building Foundations of Scientific Understanding (BFSU) came to the rescue once again.
We learned that minerals are a single, naturally occurring substance. Rocks are a mixture of two or more minerals.
Thanks to our handy-dandy rock collections I was able to pull out a sample of the most common rock, granite, as well as samples of the three minerals that granite is a mixture of (quartz, feldspar, and mica).
Kal-El was ready with the magnifying glass to go in for a closer look.
Next, each boy was given a bowl full of samples to sort according to whether it was a rock or mineral.
It was a piece of cake! The rocks were a mixture of several materials while the minerals were made from a single material and therefore had uniform color, texture, and lustre.
Next we were able to talk about something special that minerals can do if given enough space...form crystals! We'll be back with that tomorrow.