A 9-Day Geologic Time Unit That Actually Works (and Keeps Kids Engaged)

Teaching geologic time can feel intimidating—for students and teachers. Billions of years, unfamiliar vocabulary, abstract thinking… it’s a lot. Over the years, I’ve found that the key isn’t rushing through the content, but layering experiences: movement first, visuals next, practice in small chunks, and hands-on work before asking students to synthesize everything.

Here’s how I teach NGSS MS-ESS1-4 over about nine class periods, using a mix of scavenger hunts, interactive slides, partner practice, labs, and creative projects that keep students engaged from start to finish.

Day 1: Hook Them First with a Geologic Time Scavenger Hunt

Before I ever show a timeline or say the word eon, I want students moving, noticing, and asking questions.

I start the unit with this Geologic Time Stations Scavenger Hunt. Students rotate through stations, picking up bits and pieces of information about Earth’s history without being overwhelmed by structure yet. This works beautifully as:

• An engaging intro for reluctant learners
• A low-pressure way to activate prior knowledge
• A chance for students to realize, “Wow… Earth’s history is HUGE.”

By the end of the scavenger hunt, students don’t know everything—but they’re curious, and that’s exactly where I want them.

Follow up on the scavenger hunt with direct instruction. Once students have explored, then I introduce structure using an Interactive Geologic Time Scale Google Slideshow. This slideshow helps students:

• See the major divisions (eons, eras, periods)
• Understand relative time (not just memorization)
• Connect events to locations on the timeline

Because students already encountered some of this information during the scavenger hunt, the slideshow feels like answers to questions they already have, not a wall of new content.

Day 2: Rock Layers & Fossils as Evidence

Now we shift into how scientists know what happened in Earth’s past.

I teach a short lesson on:

• Rock layers (law of superposition)
• Fossils as evidence
• How both help scientists reconstruct Earth’s history

Students then practice with Geologic Time Scale Boom Cards. Boom cards are perfect for:

• Immediate feedback
• Partner discussion
• Catching misconceptions early

Boom cards are also very low risk – wrong answers are corrected privately and students can repeat the questions until they get them all correct.

To wrap up Day 2, students work independently using a self-checking worksheet. Again, these are low risk – wrong answers are corrected privately and students can continue working to get 100%.

This combination lets students practice without constantly asking, “Is this right?”

Day 3: How Fossils Form

Once students understand fossils as evidence, they’re ready to learn how fossils actually form. I use a visual-rich slide show which covers:

• Mold and cast fossils
• Petrification
• Preserved remains
• Trace fossils

The visuals really help students distinguish between fossil types—something that’s notoriously tricky at this grade level.

Day 4: Hands-On Fossilization Lab

Day 4 is where everything clicks. We simulate fossil formation and:

• Make predictions
• Observe results
• Connect the lab back to real-world fossil evidence

This lab is especially powerful for students who struggle with abstract concepts—they finally see how fossilization might occur.

Days 5–6: Mass Extinctions Guided Research

Now that students understand the timeline and the evidence, we zoom in on major events.

I use a Mass Extinctions Guided Research Station Activity in which students rotate through stations learning about major mass extinctions in geologic history. The guided format keeps research focused and prevents students from getting lost in the weeds.

Days 7–8: Build the Geologic Time Scale (Literally)

This is one of my favorite activities of the unit. Using adding machine tape, partners create a to-scale geologic time line.

Students are always shocked by:

• How much time is packed into the Precambrian
• How tiny human history is
• How recent most complex life really is

It’s one thing to see a timeline—it’s another to build one across the classroom floor.

Day 9: Review Without the Groans

To wrap up the unit, I mix independent review with partner play.

Students complete a Geologic Time Color by Number. It’s calm, focused, and great for reviewing vocabulary and sequencing.

Then we finish with a 2-player digital racing game. Students are reviewing… and they don’t even realize it.

Why This Sequence Works

This unit:

• Starts with curiosity and movement
• Builds from exploration → instruction → practice → application
• Balances movement, visuals, labs, and creativity
• Gives students multiple exposures to the same core ideas
• Supports a wide range of learners without watering down content
• Ends with low-stress review instead of test fatigue

If geologic time has ever felt like a tough unit to teach, this structure makes it manageable—and honestly, fun.

Geologic Time Unit: Lesson-at-a-Glance Pacing Chart

NGSS Standard: MS-ESS1-4
Total Time: ~9 class periods (45–50 minutes each)

Day	Focus	Learning Goal	Main Activities & Resources
Day 1	Introduction to Geologic Time	Students recognize that Earth’s history is vast and divided into major sections.	Hook: Geologic Time Stations Scavenger Hunt (movement-based intro) Direct Instruction: Interactive Geologic Time Scale Google Slideshow (major divisions, big ideas)
Day 2	Evidence of Earth’s History	Students explain how rock layers and fossils provide evidence of Earth’s past.	Mini Lesson: Rock layers & fossils as evidence Partner Practice: Geologic Time Scale Boom Cards Independent Practice: Self-checking worksheet or Winter Picture Reveal worksheet
Day 3	Fossilization Processes	Students identify and describe different methods of fossilization.	Direct Instruction: Methods of Fossilization Slideshow Discussion: Which fossil types form under different conditions?
Day 4	Fossilization Lab	Students model fossil formation and connect lab results to real fossils.	Hands-On Lab: Fossilization Activity (predictions, observations, conclusions)
Day 5	Mass Extinctions	Students investigate major mass extinction events in Earth’s history.	Guided Research Stations: Mass Extinctions Activity (causes, effects, timeline placement)
Day 6	Mass Extinctions (continued)	Students synthesize research and identify patterns across extinction events.	Station Completion & Discussion: Trends, causes, recovery of life
Day 7	Visualizing Geologic Time	Students represent geologic time proportionally using scale.	Hands-On Project: Begin adding-machine-tape geologic time scale (partners)
Day 8	Geologic Time Synthesis	Students complete and analyze a to-scale geologic timeline.	Project Completion: Add events, labels, reflections on scale and time
Day 9	Review & Assessment	Students demonstrate understanding of geologic time concepts.	Independent Review: Geologic Time Color-by-Number Partner Review: 2-Player Digital Racing Game