Rustid documented the process by which he carefully extracted and measured the peanut butter content of nine different varieties of Reese's peanut butter and chocolate candies. See below for a illustration of how he extracted the peanut butter with an Exact-o knife and used electronic scales for measurements.
Below is a graph of the various proportions of peanut butter contained within each version of the Reese's Peanut Butter Cup.
This example illustrates methodology and bar graphs.
If you are feeling especially generous, you could let your students replicate this project in class. If you really want amazing teaching evaluations, you could tell you students that you require n = 30 for each kind of candy and your students can eat the left overs.
Other points of discussion: Why did the scientist use proportions of peanut butter, not amounts of peanut butter, in his graph? Did he use proportions for the same reason that we create relative frequency graphs? What are other qualities of a Reese's Peanut Butter Cup that we could evaluate in a quantitative manner? Why isn't his graph APA style compliant? How could we conduct an experiment in order to determine which ratio is the ideal ratio? If you look through the pictures, Rustid only measured the peanut butter content of one half of each symmetrical candy. What problems may arise from this? What data should he have provided to justify this methodological decision?