EXPERIMENT: COMPARING HARDNESS AND DENSITY OF SOLIDS In this activity, you will identify several minerals, then you will compare the minerals to determine if there is a relationship between the hardness of a sample and its density. You should consider the factors that determine the density and the hardness of a material and then form a hypothesis as to whether you believe these two properties will show a correlation. If they show a correlation, it may indicate that one property depends on or is in some way related to the other property. You should consider this in making your hypothesis. If two properties have a positive correlation, then the graph of their values will be a straight line. You will use this fact to test the accuracy of your hypothesis.

OBJECTIVES
Use several tests, including hardness to identify 6 minerals.
Using hardness and density data, creating a graph.
Explain how to interpret a positive or negative correlation between graphed values.

Write a summary paragraph discussing this experiment and the results. Use the following questions and topics to help guide the content of your paragraph.

What was your hypothesis? According to your data, do you think your hypothesis was correct? (Be sure to refer to your data and graph in answering this question.)
Summarize any difficulties or problems you had in performing this experiment that might have affected the results. Describe how you might change the procedure to avoid these problems.
Explain how a graphical analysis can be used to explore the relationship between any two scientific variables.