Tuesday, April 26, 2011

Earth science HW

Finish Analysis and conclusion sections for Density of Minerals lab, including graphs and examples of calculations, into your notebooks.

  1. Gather the calculated density for each other sample from the other groups in class.  Determine the average class density for each mineral and be sure to show how you made the calculations. 
  2. Make a bar graph that compares the ave. calculated density of each mineral sample to the accepted density of the samples provided by your teacher.  Graph the mineral samples from least dense to most dense.  Include a diagram of how these samples should be found, according to their densities, if they where all in the same area of the crust.
  3. If the group average density is different from the accepted densities (greater than 10%) describe the possible errors that might have led to these differences.
Conclusion:  The following are prompts to help you write a conclusion.  Write you conclusion using complete sentences and the rubric.
Frame work: Were you able to identify the unknown minerals by calculating their density?  If no,t how did you ID the samples? i.e what other factors did you use to identify your mineral samples?   Evidence: Compare the accuracy of your density calculations to the accepted densities.  Error:  How did error influence your calculated densities?  Logic:  How do the experimental mineral densities compare to the actual densities?  Next Step:  What could be done to improve or further investigate this experiment?

Calcite ~2.7g/cm3 colorless, translucent – opaque CaCO3

Hematite (red) ~5.26g/cm3   comp mostly iron oxides found in crust (mantle)

Galena ~7.5 g/cm3  comp lead sulfide

Milky quartz ~2.6- 3.0 g/cm3  silicate dioxides crust

Magnetite   ~5.2 g/cm3  comp. iron oxides

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