Geology: Basics of Rock Textures

Rocks!  Students either love them or hate them.  Learning how to identify them can be a challenge for some students. But making it a challenge between groups of students can spark a sense of competition and a desire to learn. This can only be done after the basics of rock textures have been defined and their identification practiced.  Igneous rocks are particularly challenging to correctly identify as there are primary and secondary textures.


Understanding Rock Textures

The approach taken by Midnight Star is to use PowerPoint to name. This is by describing and showing pictures of each primary texture individually. Students then show their understanding of each by collaborating with a partner. And then using clickers to answer questions posed about the texture of the rock being examined. The power of clickers is that all students can see how the class is progressing on their understanding of rock textures. Midnight Star asks multiple questions in a row that formatively assess the same topic.  If a class clearly understands a topic (this is apparent to the entire class) then repetitive questions are skipped.  If, however, the class is struggling, reteaching occurs followed by additional questions to reassess progress.


Identifying rock samples

This is a great way to engage students in critical thinking through collaboration; skills needed in life after high school.  The process of learning how to identify rock textures and ultimately their name (thereby allowing students to identify rocks outside of the classroom) takes time. A teacher must be willing to review, or reteach, regularly once students have been introduced to this topic.  Once they have had time to practice their skills, the rock texture review worksheet can be used to help students discover their strengths and weaknesses.  When students identify where they are weak, they can focus on improving specific skills for overall comprehension.

As a geology teacher, it is most rewarding when students describe their ability. And to identify rocks outside of the classroom when they are on their own.


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