Lesson Plan — ILAW · Science 9
Term 1 · Week 3 · Domain: Force, Motion, and Energy · CG Quarter 1, competencies 4–5
⚠️ The field list is reported, not read. The four section names are consistent across sources; the sub-fields a given division expects may differ. See
source-catalogue.md§8.
This is the whole week. For Day 1 at teaching depth, see
lesson-plan.md.
| Learning Area | Science |
| Grade Level | Grade 9 |
| Term and Week | Term 1, Week 3 |
| CG source | Quarter 1, competencies 4–5 (p. 55) |
| Sessions | 5 × 45 minutes |
| Medium of instruction | English |
| Resources | slides.html · game.html · worksheet.html · worksheet-remediation.html · wall-chart.html · offline-activities.md |
| Format | ILAW — DO No. 009, s. 2026 |
I — INTENTIONS
The competency for this week
CG Quarter 1, competency 4: explain that when any two objects interact, there are equal but opposite forces exerted between them, which is evident in many practical situations and applications.
CG Quarter 1, competency 5: observe and identify action-reaction pairs in everyday situations such as stepping off a boat, or a book on a table, and draw force diagrams to explain how the pairs affect the motion of objects.
Two competencies, one week. They are not merged for convenience. Competency 4 is the statement and competency 5 is the only evidence that the statement has been understood — a learner who can recite equal and opposite and cannot name a pair has met neither.
Why it sits in Week 3
Week 1 is inertia. Week 2 is competencies 2 and 3 — acceleration as the result of a net force, and the relationship among force, mass and acceleration. Week 3 needs both of them, and it needs them in that order.
It needs the net force from Week 1 and 2 to make sense of balanced forces on one object, which is the distinction the whole week turns on. And it needs the force–mass–acceleration relationship from Week 2 to answer the question the chair demonstration raises in minute eight: how can two equal forces make two people move differently? Without Week 2, that question has no answer and the class concludes the forces were not equal after all — which is the misconception, arriving by a new route.
Week 4 leaves mechanics entirely for electricity, and Weeks 6 and 7 are the electromagnetic spectrum. So this is the last mechanics week of the quarter and the last one of the year: Grade 9 Quarter 2 is Earth and Space, Quarter 3 is Life Science, Quarter 4 is bonding. If the third law is not settled here it is not settled at all, and it is assumed by the Quarter 1 performance task in Week 8, which is a vehicle driven by action and reaction.
Success criteria for the week
By the end of the week, the learner:
- names the partner of any given force in the form B pushes A
- states that the two forces of a pair act on two different objects, and uses that to explain why they do not cancel
- distinguishes an action–reaction pair from two balanced forces on one object
- explains how two equal forces can produce unequal motion
These four are the tick boxes on observation-card.html.
II — LEARNING EXPERIENCES
| Day | Focus | What happens | Resources |
|---|---|---|---|
| 1 | Two forces, two objects | The boat, the objection, and the six words that answer it. Two chairs at minute twenty-six, then the same push with a heavier learner. The book on the table is the last seven minutes and most of the class gets it wrong. | lesson-plan.md · slides 1–13 · worksheet.html |
| 2 | The book on the table, properly | The whole session on one situation. Four forces, drawn as two diagrams — one for the book, one for everything else. Nobody leaves until they can say which object each arrow acts on. | Activity 4 in offline-activities.md · slides 10–11 · game.html Round 2 |
| 3 | Equal forces, unequal motion | The wall push and the skateboard-and-sack activity. Two learners, two masses, one force, and a measured difference in how far each travelled. | Activity 2 · slides 8–9 |
| 4 | Tug of war and the balloon rocket | Outside if possible. The rope forces are equal and the class has to find what is not equal. Then balloon rockets on a string, and the question of whether one works in space. | Activities 3 and 5 · slides 12–13 |
| 5 | Consolidation and check | The game, all three rounds. The weekly check. Worksheets returned and ★ discussed at length — it is the item most of the class will have got wrong, and it is the guide's own example. | game.html · assessment.md §4 |
The shape of each day
| Part | Minutes | What happens |
|---|---|---|
| Name the partner | 4 | Three forces on the board; the class calls the partner of each, in full sentences |
| Review | 3 | Yesterday's misconception, restated by a learner in their own words |
| Main activity | 26 | The day's focus |
| Into practice | 7 | Worksheet, game, or offline activity |
| Close | 5 | Exit ticket — one force, its partner, and the object each acts on |
Every exit ticket this week asks which object the force acts on. Not whether the forces are equal — the class will say yes to that from Tuesday onwards, correctly and without understanding. The object is the thing that is not yet automatic, and it is where the marks are.
III — ASSESSMENT
What is looked at, and when
| Instrument | Day | Component it feeds |
|---|---|---|
| Observation card — the learner's exact words | 1–5, continuous | Formative only, no mark |
| Worksheet, Sections A to D | 1 | Written Works |
| The two force diagrams for the book | 2 | Written Works |
| Measured distances from the push-off | 3 | Written Works — the learner's own pair of measurements |
| Tug-of-war written conclusion | 4 | Formative only, no mark |
| Game record, Round 2 | 5 | Formative only, no mark |
| Weekly check, 7 items | 5 | Written Works |
| Quarter 1 performance task | Week 8 | Performance Tasks |
Weights are 20 / 50 / 30 under DO No. 015, s. 2026 — see
class-record.html, which carries the transmutation year switch.
The rule that governs marking all week
A force named without its two objects scores nothing, however correct the physics sounds. There is an equal and opposite force is not an answer to what is the partner force. This is not pedantry about wording: the objects are the competency, and a learner who omits them has almost always omitted them because they do not yet know what they are.
Say the rule to the class on Monday, print it on the worksheet, and apply it without exception.
The item that reads
On the weekly check, item 6:
A book rests on a table. Its weight pulls it down; the table pushes it up. The two forces are equal and opposite. Are they an action–reaction pair? Say how you know.
Items 1 to 5 are answerable from the wall chart.
| What the learner wrote | What it means |
|---|---|
| No — both act on the book, so they are balanced forces | Full understanding |
| No, with no reason, or no, they cancel | Half. The right answer with the wrong test. Cancelling is a consequence, not the reason |
| Yes — they are equal and opposite | The diagnostic answer. Equal-and-opposite is being used as the definition. It is the default belief of most adults and it needs Day 2 repeated, not repeated louder |
| No — the table is not really pushing | A different and more interesting error. Answer it in front of the class: put a book on an outstretched palm and ask whether the palm is pushing |
IV — WAYS FORWARD
Remediation
For learners still saying equal and opposite without objects by Day 3.
worksheet-remediation.html draws no arrows at all until task 4.
Its task 3 — write the one object each force acts on — is the one that does the work, because a
learner who writes book, book, table, Earth in a column and then looks at the column has
answered the question themselves.
For learners who still think the heavier person pushes harder on Day 5.
Do not explain it again. Run the chair push-off with the two of them, and have the class measure how far each chair travelled with a tape or by counting floor tiles. Two numbers on the board end the argument in a way that no sentence does.
Enrichment
For learners who finish Day 2 early.
Draw the four forces in the book-on-a-table situation as four separate labelled diagrams — one per object involved, including the Earth. Then ask: which of those four could you feel, and which could you never detect? It is the same competency with the second law folded in.
For learners who have the whole idea by Day 3.
The rocket in vacuum, argued properly. A New York newspaper editorial in 1920 said a rocket could not work in space because there was nothing to push against, and it took the paper forty-nine years to print a retraction. Have them write the correction the editor should have printed. It is beyond the Grade 9 competency and it uses nothing beyond it.
Teacher reflection
Answer at the end of Friday:
- Write down the Day 1 §C4 vote — how many said the book's two forces were an action–reaction pair — and the number who got weekly check item 6 right on Friday. Those two numbers are the week. If the first was low, the question was asked in a way that leaked the answer.
- How many learners named both objects unprompted when they spoke by Friday? Not on paper — aloud, when nobody was marking. That habit is what survives the holiday.
- Did anyone argue that the forces cannot be equal because the outcomes were so different? That is a good objection, not a misunderstanding, and it means Week 2 landed. Answer it with mass.
Next week
Week 4 leaves mechanics for electricity — electrons flowing, safe handling, and current, voltage and resistance in assembled circuits. It does not depend on this week.
Week 8's performance task does. The guide's Quarter 1 task A is a recycled-material vehicle driven by action and reaction, carrying 15 grams over 5 metres, with the forces and vectors described. A learner who cannot name a pair cannot write that description, so the rescue point for this week is Week 8 — and by then it is the assessed task rather than a lesson.
If the class does not have it, the cheapest fix is three minutes a day for the rest of the quarter: one force on the board, the class names the partner in a full sentence, and one learner says which object each acts on. It costs almost nothing and it is the only thing that reliably works.
Part of the E-turo MATATAG artifact set. Companion files:
syllabus.md · lesson-plan.md ·
assessment.md · offline-activities.md