Lab that has students determining the material in pennies that were made after 1983. Students determine this through water displacement of pennies before 1982 and after 1983. Keep in mind that 1982 pennies will not work for this lab since both copper and zinc pennies were made in that year. Students practice graphing and finding the slope of a line as part of their analysis. I have students write formal lab reports so those headlines are included but can be modified.