Science 7–10 · Year 8

Geological time walk: 4,600 million years on a 46 metre tape

Science understanding: Earth and space sciences (NSW Stage 4 focus area: Change)

Practical, model not builtLow risk

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The idea

Rock-cycle processes take millions of years; laying Earth's history along a tape at one centimetre per million years puts all of human existence in the last few millimetres.

What you need

a 50 m tape measure or a 46 m length of string marked every metre, laid along a corridor or oval
event cards with ages from the International Commission on Stratigraphy chart (v2023/09): base of the Cambrian 538.8 Ma, end of the Cretaceous 66.0 Ma, base of the Quaternary 2.58 Ma, base of the Holocene 0.0117 Ma; and Earth's age, about 4,600 Ma, from the USGS Divisions of Geologic Time (2018)
extra event cards the teacher sources for the school's local rocks (for example the age of the Sydney Basin sandstone) with the source recorded on the card
1 calculator per group

How to do it

Fix the scale: 1 cm = 1 million years, so 4,600 million years = 46 m. Place the present at one end.
For each event card compute the distance from the present and place the card on the tape.
Walk the tape from the Hadean end, reading the cards; record how many metres of tape come before the Cambrian, when animal fossils become common.
Compute where a human lifetime (80 years) and the whole of recorded history (about 5,000 years) would sit and try to mark them.
Compare the time since the dinosaurs' extinction with the time since the Cambrian as a ratio, and express the Quaternary as a fraction of Earth's age.

What you should see

On the 46 m tape the Cambrian sits 5.39 m from the present, the end of the Cretaceous 66 cm, the Quaternary 2.6 cm and the Holocene 0.12 mm, too small to mark; a human lifetime is 0.0008 mm and the whole of recorded history 0.05 mm. About 40.6 m of the 46 m tape precede the Cambrian; the time since the end of the Cretaceous is 0.12 of the time since the Cambrian began (66 / 538.8), and the Quaternary is 0.056 percent of Earth's history. The learner knows it worked when the card positions, checked by a second group, agree to the centimetre and the Holocene cannot be drawn at all.

What changes

This activity lists no variables to change, measure and keep the same.

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

Dinosaurs and early humans overlapped; the end of the Cretaceous sits 66 cm from the present end of the tape and the whole Quaternary only 2.6 cm.
Most of Earth's history has had animals; the Cambrian, when animal fossils become common, begins only 5.39 m from the present end of a 46 m tape.
A million years and a billion years feel alike; on the tape they are 1 cm and 10 m.

Safety card

Low riskLearners carry it out

Hazards

tape across walkways

Controls

lay the tape where nobody crosses, and lift it after the walk

Note

No hazardous chemical and no flame or heating apparatus: a generic classroom risk assessment (CSIS 1.7 or RiskAssess) covers trips, spills, warm lamps and sharp edges.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Science 7-10 Syllabus (2023), NSW Education Standards Authority (implemented from 2026; codes read at curriculum.nsw.edu.au on 22 and 23 September 2026)SC4-CHG-01 SC4-WS-05 SC4-WS-06
Australian Curriculum v9AC9S8U04AC9S8I04

Sources

The pages the author read to write this activity.

All Concept Studio activities