Halfway: folding a ribbon to find the middle · Concept Studio

The idea

Half of a length is one of two equal parts, found by folding the length end to end, and the fold marks the halfway point.

Safety card

Low riskAn adult supervises

Hazards

scissors if the strips are cut
tripping on the rope

Controls

use child-safe scissors with an adult present
lay the rope flat and walk beside it

Note

No chemicals or heat are used, so the NSW Department of Education Chemical Safety in Schools package is not needed; ordinary classroom supervision under the school's usual risk management.

What you need

4 ribbons or paper strips per pair: 20 cm, 40 cm, 60 cm and 1 m long
a pencil for marking
2 chairs placed 4 m apart and a 4 m skipping rope
sticky notes to mark where children stand

How to do it

Hold the two ends of the 60 cm ribbon together, pull it straight and press the fold. Mark the fold with a pencil. That mark is the halfway point.
Fold or cut at the mark and lay the two parts side by side with their ends on a common baseline to check that they match.
Guess the middle of the 1 m ribbon and mark the guess. Then fold end to end and compare the guess with the fold.
Lay the skipping rope from one chair to the other. Stand where you think halfway is, then fold the rope end to end to check.
Stand at different places along the rope, mark each with a sticky note, and describe each place as about halfway, more than halfway or less than halfway from the first chair.

What you should see

Folding the 60 cm ribbon end to end puts the mark 30 cm from each end, and the two parts match exactly when laid side by side. Any gap between a guessed middle and the fold on the 1 m ribbon shows which part the guess made longer. The 4 m rope folds at a point 2 m from each chair. A child standing between the fold and the second chair is more than halfway from the first chair, and one standing between the first chair and the fold is less than halfway.

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.

Any cut makes two halves, so there can be a big half and a small half.
A ribbon that is curled up has a different halfway point from the same ribbon laid straight.

Curriculum references

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

Mathematics K-10 Syllabus (2022), NSW Education Standards AuthorityMAE-GM-03 MAO-WM-01
Australian Curriculum v9No Australian Curriculum v9 code is listed.

Sources

The pages the author read to write this activity.