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We have spent the last two science sessions learning all about how geologists use something called a scratch test to help determine what certain minerals are! For this test we used a penny, a paperclip, and our fingernails as tools. First we determined that a scratch is a permanent mark (that cannot be wiped away) left on one object by another. You can do a scratch test on any two objects and know that the harder object will always scratch the softer object. We spent time last session using our tools to scratch different items like a tile, and some chalk. Certain tools could scratch the items, certain ones could not.
With that in mind we spent time today using what we learned to try and identify minerals. Each table group was able to observe a tray of 4 minerals that were only labeled by numbers. The first mineral the boys and girls were to identify was Quartz. I gave them a basic clue that quartz was white, and then asked if they could tell me which one was Quartz. They quickly realized that color was not enough to identify minerals because 3 of the 4 minerals we observed were white :) Then I told them Quartz is the hardest of the common earth minerals.
We were able to deduce that if Quartz is the hardest, our best chance at identifying it would be with the hardest tool we have (which we tested was the paperclip- because it left a scratch on the penny). So we passed around the minerals, using our tools to scratch them to see if scratches were being made. We eliminated minerals that were scratched, because Quartz is the hardest and is harder than our tools. We will continue with the scratch tests tomorrow; can't wait!
