WHAT THIS MODEL HELPS US SEE
The expected-versus-observed table puts counts and percentages in the same unit and makes random variation visible.
LAUNCH · GCSE Biology · Lesson 18 of 18 · DoLAUNCH · GCSE Biology · Week 13 · Do
Inheritance Data: Predict, Calculate, Evaluate
Sequence outcome: Calculate and analyse outcomes using probabilities, ratios and percentages from monohybrid crosses.
🎯 Learning objective: I can calculate inheritance probabilities, ratios and percentages and evaluate why observed results can differ from predictions.
✅ Success criteria
- I can convert Punnett outcomes into fractions, ratios and percentages.
- I can calculate observed percentages from a dataset.
- I can compare observed and predicted outcomes and explain the role of chance and sample size.
Arrival · previous learningStarter · observe / predictI Do · model the reasoningWe Do · hinge & responseI Do 2 · connect / extendWe Do 2 · scientific model / dataIndependent · evidence & transferExit · receive and use the response
🧪 Probability Lab: compare Punnett predictions with observed seedlings without calling chance an error.⏱ 40 minutes📍 C43 only🔁 Live Lundy loop↺ Retry without penalty
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting
⏱ 3 min
🚪 Arrival · previous learningRetrieve only what has already been taught
- W13L2: Pp × Pp predicts PP, Pp, Pp and pp.
- W13L2: predicted phenotype ratio is 3 purple : 1 white.
- Lessons 10–12: a percentage needs a frequency and a total.
- Lead-in: would 31 purple and 9 white out of 40 contradict a 75% : 25% prediction?
New to this class, absent, or not sure? Everything needed is in the retrieval box above. Read it, point to it or ask a familiar adult to read it exactly.
◆ Supported
- Complete: 3 out of 4 = __%.
- Point to the recessive phenotype in the P/p model.
- Choose the total in 31 purple and 9 white.
- Lead-in: calculate 10 ÷ 40 × 100.
▲ Standard
- State the phenotype ratio for Pp × Pp.
- Convert 1/4 to a percentage.
- Calculate the total of 31 and 9.
- Lead-in: distinguish expected from guaranteed.
★ Stretch
- Explain why each offspring probability resets.
- Compare genotype ratio with phenotype ratio.
- Name one factor that makes observed proportions vary.
- Lead-in: predict how a larger sample usually affects random deviation from expectation.
LAUNCH response routes
📝 write / edit🗣 structured verbal📏 measure / calculate📊 graph / interpret🧪 practical / demonstrate↺ re-attempt
Access changes the response route, not the GCSE Biology entitlement.
🔊 Read-aloud route: a familiar adult may read the task exactly while the text remains visible. No device voice or media permission is required.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting
⏱ 3 min
🌱 Starter · observe / predictA Pp × Pp cross produced 31 purple and 9 white seedlings. Which first calculation enables comparison with 75% : 25%?
LOCAL VISUAL HOOK · FRAME 1
EXPECTED · model probability
Probability × total = expected count.
LOCAL VISUAL HOOK · FRAME 2
OBSERVED · recorded frequency
Close, not identical.
LOCAL VISUAL HOOK · FRAME 3
COMPARE · same unit, cautious conclusion
Observed differs from expected because each outcome is a chance event.
Commit one first idea. Predictions are held, not marked. Pointing, selecting, saying or signing all count.
Choose one idea. The lesson will test it; nothing is scored or saved.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting
⏱ 4 min
👩🏫 I Do · model the reasoningMake the first scientific idea visible
PROBABILITYchance of an outcomea numerical measure from 0 to 1, or 0% to 100%, describing how likely an outcome is
RATIOrelative amountsa comparison of quantities written in the same order
SAMPLE SIZEnumber observedthe total number of individuals or results included in a dataset
WHAT THIS MODEL DOES NOT SHOW
The dataset is simulated, the inheritance model assumes complete dominance and one gene, and closeness alone cannot prove the biological assumptions.
Step 1
From Pp × Pp, predict 3/4 purple and 1/4 white: 75% and 25%.
Step 2
For 40 seedlings, calculate expected counts: 0.75 × 40 = 30 purple; 0.25 × 40 = 10 white.
Step 3
Calculate observed percentages: 31 ÷ 40 × 100 = 77.5%; 9 ÷ 40 × 100 = 22.5%.
Word help keeps the scientific term visible and adds a plain-language bridge.
🎲 Expected vs observed
Pp × Pp. Probability of white = ¼. Press the expected counts, then judge the observed result.
80 seedlings — expected white?
¼ × 80 = ?
Observed 17 white of 80. Which conclusion?
Same unit (percentages) before you compare.
Foundation tier: no chi-squared test. Bigger sample → observed usually closer to expected.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting
⏱ 4 min
🤝 We Do · hinge & responseWhich comparison is scientifically correct?
Everyone commits before explanation.
Use a button, point, say/sign or let an adult operate the chosen button. A retry is information, not a penalty.
Choose one response, then use the model to explain or retry.
Audience move: the adult names back the Science heard or seen, without upgrading the pupil’s words.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting
⏱ 3 min
👩🏫 I Do 2 · connect / extendConnect the model to the second idea
Connection: the model is useful when its visible pattern is translated into a scientific explanation.
Connection 1
Use repeated batches: individual groups can vary more than the combined total.
Connection 2
A larger sample often gives an observed proportion closer to the expected probability, although exact agreement is not guaranteed.
Connection 3
Evaluate the model: useful for a simple monohybrid cross, limited for complex traits or unequal gamete/offspring survival.
MODEL STRENGTH
The expected-versus-observed table puts counts and percentages in the same unit and makes random variation visible.
MODEL LIMIT
The dataset is simulated, the inheritance model assumes complete dominance and one gene, and closeness alone cannot prove the biological assumptions.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting
⏱ 4 min
🤝 We Do 2 · scientific model / dataExpected versus observed data lab
Classify predictions, observations and valid conclusions, then repair the guarantee claim.
PREDICTCOUNTPERCENTCOMPAREEVALUATE
Cards to place
Matching groups
No statement classified. Keep expected and observed separate until both are percentages.
🧩 Science glitch · find and repair it
Claim: The observed ratio is not exactly 3:1, so the Punnett square must be wrong.
The incorrect idea is shown as a challenge, never as teaching.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting
⏱ 15 min
✏️ Independent · evidence & transferComplete a full inheritance data response: Punnett prediction, ratios, probabilities, observed percentages and evaluation.
👐 Physical route
Blank Punnett grids, simulated repeated-batch dataset, calculator, formula strip, graph paper or comparison table and pencil.
Same outcome: I can calculate inheritance probabilities, ratios and percentages and evaluate why observed results can differ from predictions.
🖥 Offline digital / director route
Use the local expected/observed lab and calculator route; results remain in session only and are not uploaded.
Same evidence: Visible working from cross to percentages, a correct expected-observed comparison and an evaluation naming chance, sample size and one model limit.
🧰 Equipment / setupBlank Punnett grids, simulated repeated-batch dataset, calculator, formula strip, graph paper or comparison table and pencil.
🛡 Safety / sensoryUse fictional plant data only. No personal genotype, family history or medical-risk calculation is requested.
🖥 Offline parityUse the local expected/observed lab and calculator route; results remain in session only and are not uploaded.
No-equipment/access route: The pupil selects the operation and dictates reasoning while an adult enters numbers, plots or scribes exact words.
📨 Next-check card
Keep this with the Lesson 18 of 18 evidence so the next assessment begins with the pupil's actual need.
◆ Supported
Complete a partly filled square, convert 3/4 and 1/4 to percentages, then choose the valid data conclusion.
Scaffold
Formula and phenotype key stay visible; totals and first calculation are pre-positioned.
▲ Standard
Build the square, calculate expected counts and observed percentages, then explain the small difference.
Scaffold
Use Predict → Calculate → Compare → Explain.
★ Stretch
Analyse repeated batches and the combined sample, then evaluate sample size and the monohybrid model's limits.
Scaffold
No chi-squared test or Higher-tier genetics; depth comes from careful evaluation.
Evidence gate
1 · Pupil decisionPrediction, question, method or choice is visible.
2 · Observable evidenceA result, source note, model state or adult observation is preserved.
3 · Pupil meaningVisible working from cross to percentages, a correct expected-observed comparison and an evaluation naming chance, sample size and one model limit.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting
⏱ 4 min
🎫 Exit · receive and use the responseFinish with an edit or re-attempt on the existing work
Supported
Convert 1 out of 4 to a percentage.
Standard
Compare 77.5% observed with 75% predicted in one cautious sentence.
Stretch
Explain how chance and sample size affect the difference between observed and predicted outcomes.
Adult Audience
The familiar adult genuinely receives the pupil response, then says back the Science they heard or saw. The adult does not add a score or rewrite the pupil.
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting
Receive the pupil’s Voice, complete real Audience, then choose what changes.
Session state is temporary. Reload clears responses; there is no account, upload or saved pupil identity.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION
LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.
🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE
SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting