Geological Timeline with Toilet Paper

Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required

Categories: Natural Selection and Evolution, Rocks, Science Shows

Alternative titles: The Toilet Roll of Time

Summary

Using 46 sheets of toilet paper to represent Earth’s 4.6 billion-year history, students create a scale model timeline where each sheet equals 100 million years. Timeline markers show that most major biological and geological events occur only in the last few sheets.

Procedure

Count out 46 sheets of toilet paper. Each sheet represents 100 million years.
Number each sheet from 0 to 45 with a marker.
On the final sheet, mark the age of Earth (4.567 billion years ago). Fold under or cut off extra paper.
Cut out timeline markers for major events (e.g., origin of life, early plants, dinosaurs, humans).
Lay out the toilet roll in a long strip on the floor.
Place the timeline markers in the correct positions along the strip.
Glue or staple the markers to the paper.
Review the distribution of events and notice that nearly all significant events are concentrated in the last 600 million years.

Links

Video lab: Paper Geologic Timeline - ScienceGonnaGetYou:

📄 The toilet roll of time - Earthlearningidea: https://www.earthlearningidea.com/PDF/234_Toilet_roll_of_time.pdf

Variations

Use a longer roll to increase resolution (e.g., 1 sheet = 10 million years).
Create a wall display version instead of a floor layout.
Add additional events, such as the rise of humans, Ice Ages, or major volcanic eruptions.
Compare geological time with a 24-hour day to emphasize scale.

Safety Precautions

Use scissors carefully when cutting the roll or markers.
Ensure enough space so the roll does not become a tripping hazard.

Questions to Consider

Why do most of the important evolutionary events occur in only the last few sheets of the roll? (Complex life evolved relatively late in Earth’s history.)
How long did bacteria dominate Earth before multicellular organisms appeared? (About 1.5 billion years.)
What does this model teach us about the scale of human history compared to Earth’s history? (Humans appear only in the last fraction of a sheet, showing our very recent arrival.)
How does this activity help us better understand geological time? (It makes the abstract concept of billions of years tangible and easier to visualize.)