RockLicker · Grade 5 · Lesson 1 of 5

Eliminate a Mineral Guess

Use conflicting evidence to reject a candidate and communicate a remaining uncertainty.

  • Grade 5
  • 45 minutes
  • Worksheet + teacher guidance
Back to Grade 5

What you will learn

A useful identification tests whether every important observation fits a candidate. Matching a color is weaker than combining hardness, luster and structure.

Words to use

  • hypothesis: an idea to test
  • conflict: evidence that does not fit
  • uncertainty: what is not resolved

Evidence for this lesson

References: quartz hardness 7, often curved fracture; calcite 3, three slanted cleavage directions; fluorite 4, four cleavage directions. Mystery data: reliable hardness 3, glassy luster, three slanted cleavage directions; pale color.

Use the supplied record as written; do not invent missing results.

Work through the activity

  1. 5 min · Set candidatesList quartz, calcite and fluorite. Read their reference hardness values and the sample observations.
  2. 15 min · Compare systematicallyMake one row per candidate with columns for hardness, luster and breakage. Mark a match, conflict or unknown in each cell.
  3. 15 min · Explain rejectionReject candidates with conflicting measured hardness. Support the remaining match with a second property rather than counting color twice.
  4. 10 min · Revise a resultImagine the hardness measurement was unreliable. State what must be rechecked and whether your confidence should change.
RockLicker
GRADE 5 · LESSON 1

Eliminate a Mineral Guess

Draw on the printed sheet or write, type or dictate your response.
Draw on the printed sheet or write, type or dictate your response.
Draw on the printed sheet or write, type or dictate your response.
Draw on the printed sheet or write, type or dictate your response.

Responses stay in this open page only. Print before closing or changing pages; no student record is stored online.

Check your understanding

A candidate fits the color but conflicts with reliable hardness. You should …

Teacher & family guide · answers and assessment

Grade 5 · Eliminate a Mineral Guess

Learning goal: Use conflicting evidence to reject a candidate and communicate a remaining uncertainty.

Expected responses

  1. Quartz: hardness conflict; calcite: compatible; fluorite: hardness conflict. All may have glassy luster.
  2. Quartz at 7 and fluorite at 4 conflict with the supplied reliable hardness 3.
  3. Calcite; three slanted cleavage directions support the hardness match.
  4. Recheck hardness under approved conditions or obtain another independent property; confidence decreases.

Understanding check: question or reject that candidate. Reliable conflicting evidence matters more than one shared color.

Watch for this misconception

Rejecting candidates from a limited list does not prove that all other minerals have been excluded.

Assess the evidence

Look for the observations, calculation or explanation named in the learning goal. Accept accurate drawings and dictated responses. Use the expected responses to discuss reasoning; a correct guess without explanation is a starting point for another conversation.

Adapt and extend

Read prompts aloud, enlarge print or let a partner record the learner’s explanation. Add a fourth candidate with unknown properties and explain why missing data cannot be treated as a match.