Research on Knowledge of the Textures of Igneous Rocks and the Ability to Identify Hand Specimens of Igneous Rocks among High-School Students

Abstract

The purpose of this research is to assess knowledge of the textures of igneous rocks and the ability to identify hand specimens of igneous rocks among high-school students. Ninety students were asked about textures and rock types for two sketches of igneous rocks, namely the equigranular texture of plutonic rock and the porphyritic texture of volcanic rock. Among the students tested, 98.9% of them answered correctly for rock types and 84.4% of them answered correctly for texture names. In addition, they were asked about rock types, namely whether plutonic or volcanic for a hand specimen of granite (polished or unpolished) or for a photograph of granite. Among 30 students, 53.3% answered correctly for polished granite, 33.3% for unpolished granite, and 40.0% for the photograph of granite. These findings exhibited that students successfully acquired knowledge of the textures of igneous rocks but that this knowledge did not lead to the acquisition of the ability to identify hand specimens of igneous rocks. It is difficult for students to recognize textures in hand specimens. Thus, the opportunity to observe hand specimens of igneous rocks should be increased in secondary schools, and instruction methods to improve students' ability to identify igneous rocks should be developed.