Abstract

The goal of the activity is to introduce students to the concept of using different mineral properties, such as streak and hardness, to identify minerals. Students are first told that minerals are classified but are not told how scientists do this. Students are then given an envelope with images of cats and dogs in it and asked to "classify" the images. Most students immediately put the animals into two groups: cats and dogs. Students then consider how they automatically classified these animals using "properties." Students learn that the most "obvious" properties, such as size and color, aren't always optimal properties to use for classification.

Context

This has been used in an introductory geology class and an introductory earth science class. Most students are non-science majors. Both classes have small class sizes. This is used as an introduction to mineral properties.

Why It Works

When asked to look at and identify minerals, the first property that most students want to use is color. However, this isn't always the most helpful one and is not the only one. This activity helps students understand that geologists also use other properties, such as hardness, to identify minerals, just as they have just used other "properties" to classify the cats and dogs.