• Sets of 'yes' example cards (various invertebrates)
• Sets of 'no' example cards (vertebrates)
• Attribute recording sheets
• Hypothesis testing form
• Classification key for animal groups
• Images of additional animals for testing
• Invertebrate characteristic chart
• Example generation worksheet

Create two sets of cards: 'yes' examples (various invertebrates like insects, worms, jellyfish) and 'no' examples (vertebrates like fish, birds, mammals). Ensure cards have clear images and names. Prepare an attribute recording sheet for students to track observed patterns. Develop a hypothesis testing form for students to record and test their ideas about the concept.

1. Introduction to concept attainment (5-7 minutes):
2. Explain that students will be detectives discovering a hidden concept
3. Clarify they'll see examples that either fit or don't fit the concept
4. Their job is to figure out what makes the 'yes' examples similar
5. Demonstrate with a simple concept (e.g., shapes that are/aren't triangles)
2. Mystery concept presentation (10-12 minutes):
3. Begin displaying 'yes' and 'no' example cards one at a time
4. Start with clear contrasts (e.g., butterfly vs. fish) and move to more subtle differences
5. After each card, label it clearly as a 'yes' or 'no' example
6. Students quietly observe and take notes on patterns they notice
7. After 6-8 examples, pause for initial thinking
3. First hypothesis formation (5 minutes):
4. Students individually write their first hypothesis about what makes something a 'yes' example
5. Remind them to focus on all 'yes' examples, not just some
6. Students record specific attributes they've noticed in the 'yes' group
4. Additional examples and refinement (8-10 minutes):
5. Continue presenting more examples and non-examples
6. Include borderline cases that challenge initial assumptions
7. After each new example, students refine their hypotheses
8. Encourage them to cross out rejected ideas and add new observations
5. Hypothesis testing (5-7 minutes):
6. Show new examples without revealing the 'yes/no' status
7. Students predict classification based on their hypotheses
8. Reveal correct classification and discuss implications
9. Refine hypotheses further based on results
6. Concept naming and verification (5 minutes):
7. Once most students have accurate hypotheses, ask for volunteers to share
8. Guide class toward identifying the target concept (invertebrates)
9. Reveal the formal definition and key characteristics
10. Compare with student-generated attributes
7. Concept application (8-10 minutes):
8. Students create their own 'yes' and 'no' examples
9. In pairs, they test each other's examples
10. Discuss any disagreements or borderline cases
11. Connect to the larger classification system of animals
8. Extension: Students create a visual organizer showing different types of invertebrates and their specific characteristics.

For younger students, use fewer examples and more obvious contrasts. For struggling learners, provide a partially completed attribute chart to guide observations. For advanced students, include more subtle examples and challenge them to create a classification system for sub-categories of invertebrates.

Review hypothesis sheets for accuracy and refinement over time. Note which students can apply the concept to new examples. During discussions, evaluate students' ability to articulate key attributes accurately. Check final examples for correct application of the concept.