Say, point, draw, sign or write. An adult may read the questions or write your answer for you.
An enzyme is a biological catalyst: it speeds a reaction without being used up. Choose: speeds up / always stops a reaction.
The fact is in the first sentence.
Amylase breaks down starch. Which is its substrate here: starch, protein or lipid?
Substrate means the substance the enzyme acts on.
To test the effect of pH, should we change pH only or change pH and temperature together?
Keep other rate factors the same.
We change pH and measure a time. Which is the independent variable: pH or time?
Independent means the factor we deliberately change.
An enzyme is a biological catalyst: it speeds a reaction without being used up. Choose: speeds up / always stops a reaction.
Answer guidance: Speeds up a reaction without being used up. Enzyme action is introduced today; this is a supplied starting fact.
Amylase breaks down starch. Which is its substrate here: starch, protein or lipid?
Answer guidance: Starch. Amylase breaks starch into smaller sugars.
To test the effect of pH, should we change pH only or change pH and temperature together?
Answer guidance: Change pH only, while keeping temperature and other relevant conditions the same.
We change pH and measure a time. Which is the independent variable: pH or time?
Answer guidance: pH. Time is the measured outcome, or dependent variable.
Say, point, draw, sign or write. An adult may read the questions or write your answer for you.
Starting fact: an enzyme is a biological catalyst. A catalyst speeds a reaction without being used up. Describe its job.
Use both parts of the supplied definition.
Starting fact: amylase breaks starch into smaller sugars. Name the substrate and the enzyme.
The substrate is what is acted on.
Why keep temperature the same when testing the effect of pH on a reaction?
Temperature can also affect reaction speed.
An investigation changes pH and times a reaction endpoint. Name the independent and dependent variables.
Changed factor versus measured outcome.
Starting fact: an enzyme is a biological catalyst. A catalyst speeds a reaction without being used up. Describe its job.
Answer guidance: It speeds up the reaction and is not used up, so it can act again.
Starting fact: amylase breaks starch into smaller sugars. Name the substrate and the enzyme.
Answer guidance: Substrate: starch. Enzyme: amylase.
Why keep temperature the same when testing the effect of pH on a reaction?
Answer guidance: So a change in time or rate is not confused with a temperature effect. It makes the comparison more valid for investigating pH.
An investigation changes pH and times a reaction endpoint. Name the independent and dependent variables.
Answer guidance: Independent: pH. Dependent: time to the defined reaction endpoint, measured in seconds.
Say, point, draw, sign or write. An adult may read the questions or write your answer for you.
Starting fact: catalysts speed reactions without being used up. How is the role of amylase different from the role of starch?
Amylase is the enzyme; starch is its substrate.
Two trials use different pH values AND different amylase concentrations. Why is this a problem?
Can an effect be attributed to pH alone?
Why repeat a reaction-time measurement at the same pH?
Think about variation and a doubtful result.
Why must everyone agree what counts as the reaction endpoint before starting a timed comparison?
The stopping rule is part of the measurement.
Starting fact: catalysts speed reactions without being used up. How is the role of amylase different from the role of starch?
Answer guidance: Amylase catalyses the reaction and can act again. Starch is the substrate converted into smaller sugar products.
Two trials use different pH values AND different amylase concentrations. Why is this a problem?
Answer guidance: Both factors could change the rate, so a difference cannot be attributed to pH alone. Keep amylase concentration constant.
Why repeat a reaction-time measurement at the same pH?
Answer guidance: Repeats show variation, help identify doubtful runs and allow a more reliable summary of the time at that pH. They do not remove a systematic error by themselves.
Why must everyone agree what counts as the reaction endpoint before starting a timed comparison?
Answer guidance: Otherwise different stopping rules may create apparent time differences. A shared observable endpoint makes the comparison more consistent.
1. Use the model to finish: “Amylase is the ___. Starch is the ___. The enzyme is not ___.”
Word bank: enzyme · substrate · used up. Trace the purple shape before and after.
2. Match pH / time to endpoint / temperature to CHANGE / MEASURE / KEEP THE SAME. Give one reason for keeping temperature the same.
Independent = change. Dependent = measure. Temperature can also change reaction speed.
3. Order method cards A–F on the reference page. Point to the actions done before mixing.
Find BEFORE (F/B), DURING (D/A), then ENDPOINT and REPEATS (C/E).
4. Point to the endpoint sample. Predict the iodine result in a separate sample with starch but no active amylase.
Blue-black = starch detected; orange-brown remains = not detected. The control still contains starch.
5. Use these results headings: pH | trial | endpoint time / s | observation. If no endpoint is seen by 300 s, choose “0 s” or “no endpoint by 300 s”.
The agreed stopping time is a limit on the observation. It is not a measured reaction time.
LAUNCH · W8L1 · Supported · 4 minutes
Say it, write it, draw it, sign it, choose it or show it; an adult can scribe it.
Plan: investigate how pH affects amylase acting on starch. Iodine turns blue-black when starch is detected; it remains orange-brown when starch is not detected. Today is preparation for the later investigation; no reaction results have been collected.
1. Why can amylase act on starch and then act again? Use the model or complete: ‘Starch fits the ___. The enzyme is not ___.’
Word bank: active site · used up · product. Choose the words that explain binding and reuse.
2. For the pH test, name what we change, what we time and one thing we keep the same.
Use the headings Change / Time until… / Keep the same. Use the detector key to finish the timing rule.
LAUNCH · W8L1 · Supported · 4 minutes
Say it, write it, draw it, sign it, choose it or show it; an adult can scribe it.
Plan: investigate how pH affects amylase acting on starch. Iodine turns blue-black when starch is detected; it remains orange-brown when starch is not detected. Today is preparation for the later investigation; no reaction results have been collected.
1. Why can amylase act on starch and then act again? Use the model or complete: ‘Starch fits the ___. The enzyme is not ___.’
Word bank: active site · used up · product. Choose the words that explain binding and reuse.
2. For the pH test, name what we change, what we time and one thing we keep the same.
Use the headings Change / Time until… / Keep the same. Use the detector key to finish the timing rule.
1. Write a testable prediction for how pH could affect amylase acting on starch. Explain why the enzyme can act again.
Use may, then link active-site binding to activity. Do not assume a universal optimum pH.
2. Name the IV and define the timed DV with units. Give three controls and justify one.
Change / measure / keep the same. Define the iodine stopping rule, not simply “how fast”.
3. Order the six method cards and explain why iodine tests separate sampled drops.
Group before / during / after. Keep iodine out of the main reaction vessel.
4. Distinguish a no-active-amylase control sample from a control variable. Predict the control result.
Constant temperature is a factor; a no-active-enzyme mixture is a separate comparison.
5. Use table headings pH | trial | endpoint time / s | observation | relative rate 1/time / s⁻¹. State what to record if there is no endpoint by 300 s.
A bounded observation is not zero. Calculate a reciprocal only for an observed endpoint time.
LAUNCH · W8L1 · Standard · 4 minutes
Say it, write it, draw it, sign it, choose it or show it; an adult can scribe it.
Plan: investigate how pH affects amylase acting on starch. Iodine turns blue-black when starch is detected; it remains orange-brown when starch is not detected. Today is preparation for the later investigation; no reaction results have been collected.
1. Explain why amylase acts on starch and can be used again.
Link complementary fit at the active site to specificity; then distinguish enzyme from substrate.
2. Name the IV, define the timed DV with units, and name one control with a reason.
The DV needs an observable endpoint. Explain how changing another rate factor would affect a comparison of pH.
LAUNCH · W8L1 · Standard · 4 minutes
Say it, write it, draw it, sign it, choose it or show it; an adult can scribe it.
Plan: investigate how pH affects amylase acting on starch. Iodine turns blue-black when starch is detected; it remains orange-brown when starch is not detected. Today is preparation for the later investigation; no reaction results have been collected.
1. Explain why amylase acts on starch and can be used again.
Link complementary fit at the active site to specificity; then distinguish enzyme from substrate.
2. Name the IV, define the timed DV with units, and name one control with a reason.
The DV needs an observable endpoint. Explain how changing another rate factor would affect a comparison of pH.
1. Predict a testable pH–activity pattern. Explain specificity and reuse without claiming that reduced activity proves permanent denaturation.
Connect mechanism to a measurable prediction. A shape model illustrates a possibility; it does not establish the pH optimum.
2. Specify the IV, operational DV and four controls. Justify two controls against competing explanations.
Operational means another person can apply the same stopping rule. Temperature and concentration could alter activity independently of pH.
3. Order method cards A–F; explain why iodine goes into separate test drops and why a consistent start matters.
Timing must start consistently with mixing. The detector must not become a second changed condition.
4. Distinguish the no-active-amylase control from a control variable. What would an unexpected orange-brown result make you check?
Use expected starch presence to reason backwards. An unexpected control questions validity before it supports a mechanism.
5. Illustrative samples: blue-black at 90 s, orange-brown at 120 s, sampled every 30 s. State the recorded time, the interval containing the threshold crossing, and one precision improvement. For another run with no endpoint by 300 s, choose a truthful table entry.
The first negative starch sample is an upper sampling bound. Choose headings pH / trial / time or no endpoint by… / observation; explain what your improvement addresses.
LAUNCH · W8L1 · Stretch · 4 minutes
Say it, write it, draw it, sign it, choose it or show it; an adult can scribe it.
Plan: investigate how pH affects amylase acting on starch. Iodine turns blue-black when starch is detected; it remains orange-brown when starch is not detected. Today is preparation for the later investigation; no reaction results have been collected.
1. Explain enzyme specificity and reuse. Predict how an unsuitable pH could affect this mechanism.
Link active-site shape, binding and product release. Do not assume that every reduction in activity proves permanent denaturation.
2. Specify the IV, endpoint-time DV with units, and one justified control for a valid pH comparison.
Make the stopping rule observable and show how the chosen control prevents a competing explanation.
LAUNCH · W8L1 · Stretch · 4 minutes
Say it, write it, draw it, sign it, choose it or show it; an adult can scribe it.
Plan: investigate how pH affects amylase acting on starch. Iodine turns blue-black when starch is detected; it remains orange-brown when starch is not detected. Today is preparation for the later investigation; no reaction results have been collected.
1. Explain enzyme specificity and reuse. Predict how an unsuitable pH could affect this mechanism.
Link active-site shape, binding and product release. Do not assume that every reduction in activity proves permanent denaturation.
2. Specify the IV, endpoint-time DV with units, and one justified control for a valid pH comparison.
Make the stopping rule observable and show how the chosen control prevents a competing explanation.
Model: 1 amylase enzyme; 2 starch substrate; 3 active site; 4 smaller sugar products. The enzyme is not used up. Method order F, B, D, A, C, E, allowing F/B swap. Blue-black detects starch; the first orange-brown remaining sample gives the endpoint. No-active-amylase control expected blue-black.
LAUNCH SCIENCE · W8L1 · Week 8 · w/c 19 October 2026
Staff copy — not for pupil books
Lead with VF in the practical and exit tasks. Written feedback is for extended writing only, strategic and not every piece (Curriculum Policy 2026/27 §14.3).
| Code | Meaning |
|---|---|
| VF | Verbal feedback given here |
| WS | Worked with support |
| I | Independent |
| NS + … | Next step one specific thing |
| E | Evidence captured on the school’s digital evidence platform |
| R | Responded loop closed (Audience has happened) |
| // | Self-edit point |
| ? | Read this back to me |
Curriculum Policy 2026/27 §14.3 summary: VF WS I NS E R (six codes; NS “next step”, E “evidence on digital software app”, R “responded to feedback”). The Feedback Policy, the code source, adds // and ? and expands NS to one specific thing and R to loop closed.
Voice + Audience = R: the pupil responds AND the adult genuinely engages with that response; add R only when both have happened. For a margin edit, the policy says: “in the same colour, on the same page”.
We do: label the enzyme model. Invite a pupil to place and explain a label, then engage with their explanation. Use VF when verbal feedback is actually given.
I've been out for a while and haven't seen your work, so today I'll start from what you show me.
LAUNCH: “Adult engages with the edit against the mark scheme / model answer before R.” The pupil owns the response; no adult counter-initial or extra receipt. Codes stay in books. No second next step or retrospective closure.
LAUNCH SCIENCE · W8 · w/c 19 October 2026
Staff copy — not for pupil books
Notice which codes appear, any unclosed NS +, and whether pupil responses are present. The policy allows an edit in the same colour, on the same page.
Read a next step set during the absence for information. Do not chase it, back-mark it or retrospectively close it. Begin fresh feedback from W8L1; never recreate a missed close.
What was actually taught? Who was in the room? What changed for any individual pupil?
Compare the current register with the names in the books. New arrivals have no prior evidence; that is not a deficit. Everyone meets the same lesson from the same page.
Use the four arrival questions, with the help used in view. An absent response is information about access and starting point, not a pupil label. Choose ONE adjustment for that pupil within the existing lesson time.
Secure: separates the reusable catalyst from the changing substrate. Partial: gives one role. Absent: no usable distinction yet. Secure → use the stretch mechanism prompt. Partial → hold the product-release model longer. Absent → point to the unchanged enzyme and use the supported stem.
Secure: identifies starch or rejects two changed factors with a reason. Partial: identifies one factor only. Absent: no link to the supplied fact. Secure → ask for the competing cause. Partial → re-read the local clue. Absent → use the supported model labels during We do.
Secure: links matching conditions or repeats to evidence quality. Partial: says “fair” or “accurate” without why. Absent: no usable reason yet. Secure → offer the stretch control question. Partial → hold the controlled-comparison example. Absent → complete the supported “keep the same because” prompt together.
Secure: separates pH from measured time, or explains a shared stopping rule. Partial: names one only. Absent: confuses cause and measure. Secure → use the timing-precision extension. Partial → point to the change/measure headings. Absent → contrast the two labelled iodine samples in the existing model.
Choose a route at each task using what the pupil shows. Switching adds no task, record or label.
Use the rates and explanation evidence to shape the plan for w/c 2 November, after half term. The book response or one exit ticket is enough; no report or form.
Made by Matt