Newsletter: Wednesday, February 18th

Our work as geologists has really taken off this week. Last week we made a list of characteristics that geologists might use to determine what minerals are present in rocks. Some of those characteristics were luster, hardness, and color. On Monday we broke up into three study groups to perform different tests on mineral samples. The tests include the streak test, scratch test, and appearance test.

 The streak test allows the students to see what color is left by a mineral when it is rubbed on an unglazed porcelain tile. We have found some really interesting results so far, for example a metallic, silver mineral left a reddish-brown streak on the tile. The colors left by minerals can be very helpful to geologists when trying to identify them.

In the scratch test, the students use their fingernail, a penny, a nail, and a porcelain tile to try and scratch the mineral. Each item has a specified hardness and if that item scratches the mineral, then the mineral is softer than that material. We discussed that this is a very important test for geologists to use, especially if they are trying to determine what materials to use for construction projects. One interesting thing we learned through our studies on hardness is that a diamond is the hardest of all substances and can only be scratched by another diamond.

The appearance test asks the students to look at minerals and identify them based on physical characteristics. These characteristics include color and luster. Luster is a new term for us in this study and there are many ways to describe a minerals luster, including: dull, waxy, greasy, pearly, silky, glassy, resinous, adamantine, sub-metallic, and metallic. 

During math this week we have been working on rounding numbers to the nearest ten and to the nearest hundred. To begin we made large number lines on the floor and worked some problems together. The kids then paired up and made number lines on their tables to use for practice. On Tuesday we played a rounding game that involved on person rolling a die and the other flipping a card to determine what their starting number would be. They then used a chip to mark their spot on the number line to serve as a visual aid to use to help them efficiently round the number to the nearest ten.