The Geologic Time Scale NGSS MS ESS1-4

In the Geologic Time Scale mini unit, students follow a recipe to make play dough and then use their dough to model superposition and relative age. Students create an illustrated booklet highlighting one interesting event in each period of geologic time.

In the extension activity, students decide if it is a good idea to clone the woolly mammoth!

Anchor Phenomenon Ideas: Choose a land feature (The grand canyon, Monument Valley) or a specific species of dinosaur (Allosaurus, Tyrannosaurus, Ankylosaurus). Find images of your land feature or dinosaur to share with students and let them discuss. Organize their discussion into a KWL chart: What do they already Know, what do they Want to know and what did they Learn. Throughout your unit, help students make connections between their questions and what they are learning about the geologic time scale.

Share this image with students and discuss - How can there be a rock older than Earth?

Make it Relevant: Geologic time is so big, it is often difficult for students to wrap their heads around. Instead, focus on imagination. Ask students to imagine what the Earth looked like during Precambrian Time or the Triassic period. Follow your students' lead and dive deep into whatever topics interest them: The extinction of the dinosaurs, the most recent ice age, the carving of the cliffs in your town - anything that gets kids engaged and asking questions!

Tips and Tricks: Learning to follow a recipe is a valuable life skill that all students benefit from practicing in question three. If possible, set up a play dough making station in your classroom and show students how to correctly measure solids and liquids. It will be messy but they will be highly engaged and ready to use their play dough to model rock layers. **1-1 gluten free flour works with our recipe in case of wheat allergies.

For two quick examples of the age of Earth, check out these National Parks Service examples with a ball of string and a stack of quarters.

The best resource for this mini unit is the book Life: The First Four Billion Years by Martin Jenkins and illustrated by Grahame Baker-Smith. Students spend hours flipping through the beautiful illustrations and the book offers many ideas for the summative assessment project.

A Brief History of geologic Time from PBS offers a fact filled overview of Earth's 4.6 billion years. This video packs a ton of information into 12 minutes! This Science News for Students article on geologic time offers a good summary as well as a color graphic of the time scale.

Extension Activity: Students love to debate the pros and cons of bringing the woolly mammoth back to life! This Nat Geo article explains how scientists could do it and the Revive and Restore Project explains the connections between woolly mammoths and climate change. Students are highly engaged in this project and we encourage building in additional time so all students can complete at least part of this extension.