Technologies K–10 · Years 1–2
A yes/no sorting machine: branching with attribute shapes
Design and Production (NSW Science and Technology K–6, 2017) (algorithms); Digital Technologies: Processes and production skills, Generating and designing (ACARA v9)
This site has no interactive model of its own. Where a step or a material names a Concept Studio model, simulation or tool, it has not been built; an external simulation a step names (for example PhET) is not part of this site.
The idea
A branch is a question with two answers that sends each item down a different path, so two yes/no questions in a row sort 12 shapes into 4 groups.
What you need
- 12 attribute shapes: triangles, squares and circles, each in red and in blue, each big and small (3 × 2 × 2 = 12)
- A floor-tape flowchart: one diamond 'Is it a triangle?', then on each of its two arrows a diamond 'Is it red?', ending in 4 labelled boxes
- Sticky notes for predictions
How to do it
- Walk one shape through the flowchart: at each diamond answer yes or no aloud and step along that arrow.
- Before sorting the rest, predict how many shapes will end in each of the 4 boxes.
- Sort all 12 shapes and count each box.
- Swap the questions so 'Is it red?' comes first, sort again and compare the counts.
- Change one question to 'Is it big?' and predict the new counts before sorting.
What you should see
With 'Is it a triangle?' first and 'Is it red?' second, the boxes hold red triangles 2, blue triangles 2, red shapes that are not triangles 4 and blue shapes that are not triangles 4, 12 in all. Swapping the questions gives the same four groups with the same counts, because each shape has one answer to each question. With 'Is it big?' in place of 'Is it red?' the counts are again 2, 2, 4 and 4. The learner knows it worked when every shape lands in exactly one box and the four counts add to 12.
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.
- A yes/no question can only sort into two groups (two questions in a row make four groups).
- Changing the order of the questions changes which group a shape belongs to (each shape keeps the same answers).
- Computers can answer 'maybe' at a branch (each branch takes exactly one path).
Safety card
Hazards
- Tripping on floor tape
Controls
- Tape pressed flat; walk, do not run, on the flowchart
Note
No chemicals or heat. Record the activity on Primary School RiskAssess (riskassess.com.au).
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), NESA. The syllabus taught in 2026; the 2024 syllabus replaces it from 2027. Code read from the official syllabus document (DOCX) on 2026-09-22.ST1-3DP-T
- Science and Technology K–6 Syllabus (2024), NESA. Implementation from 2027, so this code describes the future syllabus. Code read from the outcomes page on 2026-09-22.ST1-DDT-01
- Australian Curriculum v9AC9TDI2P02
Sources
The pages the author read to write this activity.