Junior+Geology+Page+4

Session 7: Moh's Hardness Scale; Cleavage.
Students were introduced to the speed of light in minerals through the different light properties of garnet, calcite and quartz crystals. For example, Mark used a piece of calcite to show two images appearing as the sample was rotated. He explained this is because a calcite crystal has two speeds of light and so is described as showing dispersion. Children were introduced to Moh's Hardness scale and streak as tools for mineral identification and examined several kinds of mica, discussing the differences in their properties. The children used dental probes to split off a thin sheet of muscovite to illustrate cleavage.


 * [[image:100_0769-1.jpg width="358" height="270" caption="Moh's Hardness Scale: Recording results."]] || [[image:100_0770-1.jpg caption="Millie, splitting a thin sheet of muscovite"]] ||

Session 6: Identification of rocks by density.
Children were introduced to the method of identifying a rock by working out its density and matching the result with a table of rock densities. The experiment was motivated by the need to prove that the rock the students identified as rose quartz, based on look alone, was in fact what they thought it was. After working out the density, the rock proved to be aragonite. Samples of minerals ready for measuring. || Amy preparing the empty jar and water. || Weighing the empty jar, water and the sample of rock to be identified. || Tristan's calculations using an equation to work out density. || Checking the result, using notes accompanying the PeriodicTable. || Leo calculating the density that proved the "rose quartz" was in fact aragonite. ||
 * [[image:P1070466-1.JPG width="207" height="161"]]
 * [[image:P1070469-1.JPG width="209" height="152"]]

__**July Fieldtrip to Woodside Glen and the Geology Museum, Otago University.**__

Children went into the field to identify some of the concepts explored in the Workshop sessions. At the Woodside creek they were shown how sieves worked for sorting sediment; identified metamorphic rocks and some of the minerals associated with them; looked at the range of particle and rock sizes in the creek bed; talked about the river energies required to shift different sizes of rocks, how the slope of the creek relates to its energy and compared it with the slope and sediments found in the Taieri River out on the plain. They then identified the fault zone by looking at the relevant elevations and materials of the large schist rock-blocks in the area.

At the Geology Museum, children examined the rock specimens in the quadrangle. Inside the Museum They looked at samples of rock illustrating age and time sequences based on the comparison of the fossils they contained, were introduced to the large geological wall maps of the Dunedin Rock sequence and were inspired by cabinets of beautiful minerals.