STEM Tuesday– Geology — Writing Tips & Resources

STEM Tuesday

Layering It On

This month’s #STEM Tuesday book list focuses on geology, which Merriam-Webster defines as “a science that deals with the history of the earth and its life especially as recorded in rocks.”

In reading this month’s books, I was struck by all the images of rock layers, including this one from Jen Swanson’s OUTDOOR SCHOOL: Rock, Fossil, and Gem Hunting.

An image of rock layers

I learned that every layer gives us a piece of  information about the Earth’s history. Some layers have fossils revealing how long ago the layer formed. Others contain rocks and sediment that tell us if water was involved in deposition. Taken together, these layers help us see the big picture about Earth’s history.

Text Features — A Book’s Layers

Books are layered just like the Earth. Text features are the layers that help readers understand the book’s content. These text features include elements like captions, graphics, and labels. Let’s take a look at the graphic below from from DIRTMEISTER’S NITTY GRITTY PLANET EARTH by Steve Tomecek to learn more about text features.

  • Table of contents – Normally found at the beginning of the book, a table of contents is like a map. It tells you the topics the book will cover and how to find them by listing the page numbers. 
  • Subheadings – Often nonfiction chapters are carved up into smaller chunks, each with its own subheading. These subheadings tell you exactly what the next section of text is about.
  • Illustrations/photographs – You know that saying, “A picture’s worth a thousand words?” Just think how much easier it is to show you the tectonic plates in the image above, rather than trying to describe what them using text. Illustrations and photographs convey information that may be more difficult to describe in the text.
  • Captions – These are most often found under an image. They normally are a sentence or two long.
  • Labels – These are snippets of information placed on an image itself. Labels call out parts or features of an image, like the labels I’ve used in this graphic to call out the various text features.
  • Sidebars – Sidebars have additional information related to the main part of the text.
  • Graphics like graphs and charts– These organize information visually. They are especially helpful for showing processes or giving meaning to numbers.
  • Maps- Show you important locations mentioned in the text.
  • Special print (typography) – Sometimes print is bolded, like glossary words the author wants you to know. Italics and underlines provide emphasis.
  • Index – Found at the end of a book, an index is alphabetized, helping you quickly look up ideas, concepts, and names and find which pages will tell you more.
  • Glossary – Gives definitions for bolded words in the text. Think of it like a little dictionary in the book.

Teaching About Text Features

Have students look at some of the books on this month’s Geology list, then:

  • Consider creating a bingo card of text features for students to cross off as they find them.
  • Ask: Did students find any other text features not mentioned? How do they add to their understanding of the book?
  • Without reading the main text, have students look only at the text features and make some guesses about what they believe the main text is about.
  • Challenge students to incorporate text features in their next piece of informational writing.

Kirsten Williams Larson author

Kirsten W. Larson


Kirsten used to work with rocket scientists at NASA. Now she writes books for curious kids. She is the author of WOOD, WIRE, WINGS: EMMA LILIAN TODD INVENTS AN AIRPLANE, illustrated by Tracy Subisak (Calkins Creek, February 2020), A TRUE WONDER: The Comic Book Hero Who Changed Everything (Clarion, Sept. 28, 2021), illustrated by Katy Wu, and THE FIRE OF STARS: The Life and Brilliance of the Woman Who Discovered What Stars Are Made Of, illustrated by Katherine Roy (Chronicle, Spring 2022), as well as 25 nonfiction books for the school and library market. Find her at or on Twitter and Instagram @KirstenWLarson.

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1 Comment
  1. Great post, Kirsten. I love the analogy of book layers like sediments.