Earth and Environmental Science 11–12 · Year 12
Building and testing a simple seismometer
Module 6: Hazards
The idea
A mass that lags behind a shaking frame records the ground motion, the principle of every seismometer from a pendulum and pen to a digital sensor.
What you need
- a frame (cardboard box or retort stand), a heavy mass on a string or spring, a fine felt pen touching a strip of paper pulled at steady speed
- or a micro:bit with its accelerometer logging to a laptop (Geoscience Australia instructions)
- a bench to thump, a stopwatch, a ruler
How to do it
- Hang the mass so the pen just touches the paper; pull the paper steadily and mark seconds on it.
- Thump the bench at a known distance and record the trace; repeat at two other distances and with two strengths.
- Measure the trace amplitude for each and tabulate against distance and strength.
- With the micro:bit version, log acceleration during the same thumps and compare the two records.
- Discuss what the instrument can and cannot tell (timing and relative size, but not location from one record).
What you should see
The trace shows a burst that dies away; amplitude falls with distance and rises with thump strength, and the pen version gives a clear time of arrival from the paper marks. The digital record shows the same burst with a numerical peak acceleration, which the learner can compare across thumps.
What changes
- What you change
- distance and strength of the source
- What you measure
- trace amplitude
- What you keep the same
- same mass and pen pressure
- same paper speed
- same bench
Common misconceptions
Each of these ideas is wrong, and the activity is a chance to test it.
- A seismometer measures the size of the earthquake directly (it records local ground motion).
Safety card
Hazards
- falling mass
Controls
- clamp the frame
- mass below 500 g
Note
No hazardous chemicals or heat sources: record the activity in the school's RiskAssess risk assessment, following the NSW Department of Education Science safety and compliance page; the Chemical Safety in Schools package is not triggered.
Curriculum references
The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.
- Earth and Environmental Science Stage 6 Syllabus (2017), NESA; current, replaced by the 11–12 Syllabus (2025) from 2028EES12-13EES11/12-1EES11/12-2EES11/12-3EES11/12-4
- Earth and Environmental Science 11–12 Syllabus (2025), NESA; to be implemented from 2028, not yet taughtEES-12-02
- Australian Curriculum v9No Australian Curriculum v9 code is listed.
Sources
The pages the author read to write this activity.