Spark has been studing about rocks and how to identify them using a couple different scales. One of those scales is the Mohs Scale of Hardness. Frederich Mohs, a German mineralogist, devised the scale in 1812 by selecting the ten minerals because they were common or readily available.
By determining how hard your rock is by scratching it you can get one step closer to figuring out what kind of rock it is.
So for the last week my Wii Fit Plus disc hasn't been working very well and the last couple of days hasn't worked at all. A closer look told me that we haven't been putting it gingerly back in it's case everytime it is taken out of the Wii. It was full of scratches and smudges. Today, when I was in town, I bought a new one. It was hard to find just the disc not the whole new game with the board so I don't want anything to happen to this one.
Spark was taking it out of the Wii to put another disc in and I told him, "Handle it like it is a diamond." Then on second thought I said, "No, handle it like it is talc. Do you know what that means?" And he did! Woo hoo, he does listen to our science lessons!