Hold up five real leaves or laminated leaf cards (oak, holly, dandelion, daisy, fern) so the class can see them. Do not name them yet. Ask: What is different about these leaves? Accept quick observations — shape, edges, size — then move on. Keep the hook light: no key structure yet. One line of Irish context is enough: these are plants children may pass at break or see in hedges and lawns.

Before the lesson: print the provided leaf cards if you cannot collect real leaves; check the school garden for safe collecting spots; have hand magnifiers ready.

Teach the three words briefly before sorting. Project only the short board text; keep the full table for yourself. Do not run a long colour-versus-edge debate yet — children have not observed the leaves together. After Step 3, when edges and shapes are fresh, you can say: colour can change in autumn or after a dry week, but shape and edge stay steadier, so they make fairer yes/no questions.

Nature of STEM: A branching key (sometimes called a dichotomous key) was invented so people could name living things the same way every time. Naturalists in Ireland, including Robert Lloyd Praeger, used careful grouping and keys when they recorded Irish plants and animals. The idea is still used today in field guides and apps.

Misconception to head off: children may think any difference will do. Steer them toward features that are clear and stable — shape and edge, not colour or size alone. Hold that point until after the leaf look in Step 3 so they can point at real edges.

Before the lesson

Gather real leaves from the school grounds if you can, or print the provided laminated leaf cards (oak, holly, dandelion, daisy, fern) — one set per group. Check for allergies and do not pick anything spiky or unknown beyond the known holly sample already provided.

During the step

Take the class outdoors briefly if weather allows, or work at tables with collected or laminated leaves. Each group handles the five leaves and talks about features. Circulate and prompt: Is the edge smooth or jagged? Is the leaf one piece or many small parts? Does it feel prickly?

Expected features to draw out:

• Oak — deep wavy lobes, not prickly
• Holly — stiff, shiny, prickly edges
• Dandelion — long leaf with deep jagged teeth, often one piece
• Daisy — small, smooth-edged, spoon-shaped leaves near the ground
• Fern — divided into many small leaflets along a stem

Strong vs weak features (after they have looked): colour can change in autumn or after a dry week. Shape and edge stay clearer, so they make fairer questions for a key. We will use those kinds of features on the board next.

Safety: do not pick unknown plants; wash hands after handling; mind holly prickles.

Differentiation: less confident groups get sentence starters on the board (The edge is… The shape is…). Confident groups can suggest a second feature for each leaf.

Drive the sorting-tree interactive on the IWB in explore mode. Five item cards appear: oak, holly, dandelion, daisy, fern. Four yes/no questions guide the sort so each leaf reaches its own end point. Terminal groups on screen are the five leaf names: holly, fern, oak, dandelion, daisy.

Full path (model this aloud):

• Prickly edges? Yes → holly. No → next question.
• Many small leaflets (small parts along a stem, like the fern)? Yes → fern. No → next question.
• Deep wavy lobes? Yes → oak. No → next question.
• Deeply jagged or toothed edge? Yes → dandelion. No → daisy.

Worked model (say this aloud before pupils copy the idea into their journal):

• I wonder which question splits the pile first.
• I predict prickly edges will pull holly out on its own.
• I test: holly is the only prickly one — yes path ends at holly.
• I observed fern is the only one with many small leaflets.
• I think a good first question is one that cleanly splits one leaf from the rest, and we keep asking until only one name is left.

Invite pupils to call out yes or no for each leaf. Fold the watching class in: Do you agree? Which question would you ask next? Briefly revoice why we used edge and shape, not colour alone.

After the class tree is built, pupils record the same key on their Investigation Journal page: the four questions in order and which leaf sits at each end point. Say only what to record (questions and final leaf names), not box titles on the page.

Then do two or three quick oral checks on the finished tree (e.g. Where does holly go? Where does fern go? Where does daisy go?) so the class checks every leaf has one clear end. Stay in explore mode; do not rely on an on-screen challenge bank for this step.

Setup

Give each group one mystery leaf (real or a card) from the same set of five, face-down or in an envelope so the name is hidden. Use a different leaf for different groups if you can so answers vary. The class key from Step 4 now ends on a single name for every leaf, so any of the five is a fair mystery.

Investigation cycle

Prompt groups to:

• Predict which leaf they think it is before using the key
• Follow each yes/no step in order
• Land on a name and check it against the real leaf features

What to expect: most groups will identify correctly if they stick to the key. If two groups disagree, walk both paths on the board and find where a feature was misread (common slip: calling dandelion's jagged edge prickly, or missing oak's deep wavy lobes).

Key questions: Which question did you answer first? What would happen if we started with a weak question like colour?

Differentiation: support groups by sitting with them for the first yes/no. Stretch: ask a group to invent one extra yes/no question that would still separate oak from dandelion.