Science and Technology K–6 · Year 3

Solid or liquid? Testing properties, then meeting cornflour slime

Science understanding: Chemical sciences

PracticalLow risk

The idea

Solids keep their shape and liquids take the shape of their container and can be poured, and testing those properties on a cornflour and water mixture shows why scientists test rather than assume.

What you need

samples: wooden cube, sponge, sand in a cup, honey, water, cooking oil, playdough
1 cup maize cornflour (labelled 100 percent maize or corn starch; wheaten cornflour works poorly), about 130 g, and about 100 mL water in a bowl
3 clear cups and a funnel
kitchen balance
recording table with columns: keeps its shape, can be poured, takes container's shape, can be squashed

How to do it

Test each sample against the four properties and tick or cross each column.
Sort the samples into solids and liquids and explain any that were hard to place (sand pours but each grain keeps its shape).
Mix the cornflour with water a little at a time until it flows slowly when tilted but resists a quick poke.
Test the mixture: pour it slowly, then punch it quickly, then roll it into a ball and stop rolling.
Record which properties it shows under slow force and under fast force.
Write a claim, with evidence, about whether it is a solid or a liquid, and what a test tells you that a look does not.

What you should see

Wood, sponge and playdough keep their shape; water, oil and honey pour and take the container's shape (honey slowly). Sand pours as a heap of tiny solids. The cornflour mixture flows and takes the cup's shape under slow force but resists and cracks under a quick blow, and a rolled ball slumps as soon as rolling stops: it behaves as a liquid slowly and a solid quickly (a shear-thickening suspension), which is why it needs a test, not a glance.

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.

Anything soft is a liquid.
Powders are liquids because they pour.
Cornflour slime is a new state of matter (it is a suspension of solid grains in water).

Safety card

Low riskLearners carry it out

Hazards

slip hazard from spills
food allergens

Controls

work over trays
no eating
dispose of slime in the bin, never the sink

Note

Risk assessment before the lesson using Primary RiskAssess or the school's own template.

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 and Technology K-6 Syllabus (2017), current, taught until 2026; code read from the syllabus document on 22 September 2026ST2-6MW-S ST2-1WS-S
Australian Curriculum v9AC9S3U04AC9S3I01AC9S3I03

Sources

The pages the author read to write this activity.

All Concept Studio activities