Geography K–10 · Years 7–8

Dune formation: wind over bare and planted sand

Landscapes and landforms (ACARA Year 8 sub-strand); NSW Stage 4 focus area Landscapes and Landforms (2015 syllabus) and Landscapes and landforms (2024 syllabus)

PracticalMedium risk

School laboratory, not for home

In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.

The idea

Wind moves dry sand grains and drops them where the wind slows, so any obstacle including plants starts a dune and holds it.

Safety card

Medium riskA teacher supervises

Setting: In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.

Hazards

respirable crystalline silica dust from dry play sand blown into the air
blown sand in eyes
electrical appliance near sand

Controls

run outdoors in the open air only: never indoors and never inside a box or a hood of any kind, which would hold the dust in the breathing zone; the tray at or below waist height
dryer on its lowest cool setting and clamped; nobody downwind of the tray at any time; observers upwind and at least 2 m to the side, with only the learner running the dryer beside it
safety glasses for everyone within 2 m; the four 60 s runs are the whole of the exposure and the dryer is switched off between them
clean up damp: mist the tray, the catch paper and the ground with water before the sand is tipped back, wipe surfaces with a damp cloth, and never dry-sweep or brush the dust; hands and faces washed afterwards

Note

Nothing is added to the sand and no heat is used, but blowing dry play sand about generates airborne dust and play sand is silica sand. Respirable crystalline silica has an eight-hour time-weighted-average workplace exposure standard of 0.05 mg/m³ set by Safe Work Australia and is the dust behind silicosis, which is why this run is outdoors with nobody downwind, the exposure is held to four 60 s runs, and the clean-up is damp rather than swept. Record the practical in RiskAssess (riskassess.com.au) with the dust hazard named. The NSW Department of Education Chemical Safety in Schools package is not triggered, because no chemical is added.

What you need

Tray 60 cm × 40 cm with 2 cm of dry fine play sand levelled; play sand is silica sand and this method deliberately puts it into the air, so read the safety block before any run
Hair dryer on the cool setting, clamped at one end 10 cm above the sand, or a desk fan
20 toothpicks with paper flags as "plants", grass clippings
Ruler, stopwatch, kitchen scales, a sheet of paper at the downwind end to catch sand

How to do it

Run the dryer for 60 s over bare sand. Weigh the sand caught on the downwind paper (g) and measure the height of any ridge that forms (mm).
Re-level. Plant 20 toothpicks in a 10 cm band across the middle of the tray. Run 60 s again; weigh and measure.
Re-level. Spread grass clippings over the same band; run 60 s; weigh and measure.
Re-level and run at a lower dryer distance (stronger wind) over bare sand for 60 s; weigh.
Tabulate sand moved past the end (g) and dune height (mm) for each run.

What you should see

Bare sand: grains bounce along the surface and a measurable mass reaches the paper; a low ridge forms in the lee of any irregularity. With the toothpick band a dune is expected to build on the upwind edge and in the lee of the band, with less sand reaching the paper; stronger wind moves more. The grass clippings may hold the sand or may blow away themselves; either is recorded, because loose cover without roots is a result about why dune plants matter. The learner reports grams and millimetres for the four runs and compares them with the prediction that cover reduces the sand passed.

What changes

What you change: surface cover (bare, sticks, grass) and wind strength
What you measure: mass of sand moved past the end (g); dune height (mm)
What you keep the same: run time 60 s
sand depth and dryness
dryer position for the cover runs

Common misconceptions

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

Dunes are piles the sea leaves behind.
Plants on a dune are decoration; the dune would be there without them.

Curriculum references

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

Geography K–10 Syllabus (2015), NESA; current and taught in 2026, replaced from 2027. The outcome codes are not printed on the NESA landing page for this syllabus, which only links the document, so the url given is the syllabus document itself (geography-k-10-syllabus-2015.docx); the code and its outcome text were read in that document on 23 September 2026.GE4-2 GE4-5
Geography 7–10 Syllabus (2024), NESA; implementation from 2027, not yet taught; code read on this page on 22 September 2026GE4-PRI-01 GE4-MAN-01
Australian Curriculum v9AC9HG8K01AC9HG8K04AC9HG8S03

Sources

The pages the author read to write this activity.

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