Thursday, February 13, 2014

E SciDensity of Minerals Lab guide sheet Due 2/24 + 25

Directions: record rough drafts of the lab (Q, H, T, M, P w/diagram & D) individually into your science notebook.  The final draft will include writing a Lab write up, according to the supplied rubric for Lab Write-ups, in a Microsoft Word document with data analysis completed using Microsoft Excel and inserted into the Lab Write-up.

Question: How Can the density of  minerals be accurately determined (within 10%) by measuring their volume and mass using a graduated cylinder and a metric balance?

Hypothesis:  Through the use of water displacement to determine volume and using a metric balance, students will be able to accurately (within 10%) determine the density of known mineral samples.

Test:  Hint: Use the question, test and materials to design a brief one or two sentence statement of how you will find the density of the mineral samples and compare them to accepted values provided by your teacher.

Materials:  100 ml graduated cylinder, metric balance, water supply, unknown mineral samples, paper towel and any other materials you use Milky Quartz, Galena, Magnetite, Calcite and Hematite samples

Procedures:  Work with your group mates to determine how you will collect data using each material to conduct the experiment.  Your procedures should be descriptive step by step instructions which include a diagram that will visually illustrate the more complex procedural steps.  Remember that Density (D) = Mass (m) / Volume (v) and should be in g/cm3.

Data Table:  Construct in your notebook, place data collected there.

Physical Description of Mineral
Measured mass in g
Measured volume in  cm3
 (1ml =1cm3)
Calculated Density in
Name of mineral

            Observations of data collection:  Write these descriptions in your notebook


  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.
  4. Find % error for you class ave. of each mineral using the formula: {accepted – experimental /accepted} X 100%, where brackets indicate to take an absolute value.

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 not, 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?

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