OuiSi · Science

Sort it your way

Beta

Grades K–5 Teaching 35 min Plus 2 to set out, 2 to clear Class any size Set any Prep none

set out 2′ Pick one rule 10′ Guess my rule 10′ Same cards, new rule 10′ Close 5′ clear 2′

Goal: Children classify by a rule they invent, defend it, then find that the same cards sort a completely different way. Classification is a choice, not a discovery.
Materials: One OuiSi Photo-Card set. About twelve cards per group of four.

K–1: Two piles. Stop after guessing each other's rule — about 25 min
Grades 2–3: Three piles, then re-sort with color banned — the full 35 min
Grades 4–5: The second rule must be invisible in any single card — the full 35 min

1 · Pick one rule

10 min

Groups of four, about twelve cards spread face up.

Sort these into piles. You pick the rule, and you only get one rule.

Do not tell me what it is.

One rule, kept secret. Both parts matter — one rule forces a clean criterion, and secrecy sets up the next step.

To a group that is stuck, offer examples rather than answers.

Color. Shape. Rough or smooth. Alive or not alive. Things that could fit in your hand.

2 · Guess my rule

10 min

Groups move one place around the room and look at the sorted piles in front of them.

What was their rule? Do not move anything — just look.

They write a guess, then the owning group says whether it is right.

Guesses are often wrong and almost always reasonable, which is the finding. The same piles support several rules, and children discover that without being told.

If their guess was not your rule, was it still a fair way to describe your piles?

3 · Same cards, new rule

10 min

Back at their own table, cards swept together.

Sort them again. New rule, and it cannot be about color.

Banning color is what pushes the second sort past the obvious. Texture, light, stillness, and age all start appearing here.

To finishers.

Is there a card that would not fit either time?

4 · Close

5 min

Which rule told you more about the cards? Your first one, or your second?

There is no correct answer. Children argue it well, and the argument is the understanding.

Watch for

Looking for the right classification. There is not one, and saying so plainly in step one saves ten minutes of hand-raising.
Two rules smuggled in as one. Big blue things is two rules. Ask which one they would keep if they could only have one.
Piles of one. If every card has its own pile, the rule is too specific. Ask for three piles maximum and the rule tightens itself.
Children who like rules do well here — give them the target of the fewest piles that still work.

Adapt

Multilingual learners — sorting needs no English. Guessing the rule can be done by pointing at two cards and shrugging.
Autistic children — a precise, strictly applied rule is exactly what this lesson asks for. Let it stand rather than asking them to broaden it.
Tie to a unit — name the rule yourself for one round: living and non-living, natural and made, solid and liquid.
Wide ability range — mixed groups, since there is no answer key to fall behind on.

Curriculum links. Classifying by a rule you invent · Inferring another group's rule from their piles alone · Judging whether a different description is still fair · Re-sorting the same set by a second rule · Treating classification as a choice, not a discovery.
Standard codes vary by state and district — these are the skills exercised, for you to map to your own.

Screen-free. No codes and no devices. Works with any OuiSi Photo-Card set.
Extension. Each group writes their rule on a card and the class sorts the rules themselves.