A Bendemeer parent considering Primary 6 PSLE Science tuition may see a child use shadow size as though it were a direct measurement of the object. A larger shadow appears on a screen, and the child says the object must have grown. The missing step is checking the positions of the light source, object and screen.
The weekday versus weekend decision should make room for that setup-to-result explanation. A useful lesson identifies what stayed fixed, what moved and what the measured shadow supports. A later changed record reveals whether the child can reason from the conditions rather than a familiar picture.
This guide uses illustrative paper records with one small light source, an opaque object and a screen. It is a point-source school model, not a rule for every lighting arrangement. Match the reasoning to current work, readiness, actual PSLE course and examination year; no home investigation is required.
eduKateSG · Primary 6 PSLE Science · Bendemeer
A larger shadow: check what moved before concluding that the object grew
Find your next step
Choose a reading route below, or open the chapter index. Each route leads to two expanded chapters. The worked example and independent check use changed details to help you inspect understanding.
READING ROUTE 1 · CHAPTERS 1–2
Check what moved
Separate a larger shadow from the claim that the object grew.
READING ROUTE 2 · CHAPTERS 3–4
Read the worked case
Compare screen positions, then consider a weekday session.
READING ROUTE 3 · CHAPTERS 5–6
Build a return routine
Consider a weekend window and repair a result-only conclusion.
READING ROUTE 4 · CHAPTERS 7–8
Check fresh measurements
Use changed distances and match planning to the actual course and year.
READING ROUTE 5 · CHAPTERS 9–10
Plan the next step
Read the parent questions and bring a setup-based explanation to the programme conversation.
Open the chapter index · Try the independent check · View the Primary 6 Science programme
Full chapter index
Chapters 1–5: understand, work through and compare lesson days
Chapters 6–10: repair, check and plan the next step
CHAPTER 1 OF 10 · Check what moved
1. Find what the child thinks the shadow measures
Ask why the larger shadow means the object grew. If the child assumes the two widths must always match, the next lesson should examine the projection setup. A shadow’s size can change when the geometry changes even if the object itself is unchanged.
Keep the original reason as well as the answer. ‘Compared shadow widths but ignored that the screen moved’ gives the teacher a precise target. Repeating light vocabulary alone may leave that interpretation unchanged.
Start with the supplied conditions. Is there one small source? Is the object fixed? Does the screen remain perpendicular to the central light path? Those details prevent applying an explanation from a different arrangement without checking whether it fits.
CHAPTER 2 OF 10 · Check what moved
2. Connect straight-line light paths with screen position
In this model, light travels in straight lines from a small source, and an opaque object blocks some of those paths. The blocked region is projected onto the screen. Its size depends on the relative positions, not only on the object’s size.
The Singapore Open Source Physics light-and-shadow resource describes the effect of screen distance on shadow size. With the source and object fixed in the stated arrangement, moving the screen farther beyond the object gives a larger projected shadow.
The University of Iowa’s point-source demonstration also uses a source, object and screen to investigate shadow changes. Our paper task needs no advanced ray calculation or claim about every real lamp or sunlight arrangement.
Imagine a small source and a flat opaque object held fixed, 20 cm apart. The object’s width remains 2 cm and its orientation is unchanged. A screen is moved along the same line, kept perpendicular to it, with the whole shadow fitting on the screen.
In record A, the screen is 20 cm beyond the object and the measured shadow width is 4 cm. In record B, it is 40 cm beyond the object and the shadow width is 6 cm. These are illustrative measurements consistent with the stated model.
The larger shadow in B is explained by the changed projection distance, not growth of the object. The question explicitly keeps object width unchanged. Doubling the object-to-screen gap also did not double the measured shadow width: 6 cm is not twice 4 cm.
| Record | Object-to-screen gap | Source-to-screen distance | Measured shadow width |
|---|---|---|---|
| A | 20 cm | 40 cm | 4 cm |
| B | 40 cm | 60 cm | 6 cm |
CHAPTER 4 OF 10 · Read the worked case
4. Use weekday tuition when the setup error is recent
A weekday lesson may fit when your child has recently received feedback on a light experiment. Bring the record and ask which condition they thought changed. The teacher can compare that assumption with the statement that only the screen moved.
Consider attention after school. A focused comparison of two screen positions may work in a calm evening. If the child repeatedly ignores the setup captions, a longer worksheet may mainly practise making claims from the result column alone.
Leave a short return on another day. Change the distances and measured widths while retaining the fixed object. Ask what the larger shadow supports and what it does not establish. Note whether the child independently checks the unchanged object size.
CHAPTER 5 OF 10 · Build a return routine
5. Use weekend tuition for an unhurried three-position comparison
A weekend session may suit a child who needs time to distinguish source position, object position and screen position. The teacher can name what is held fixed before examining the shadow record, making the reasoning less dependent on a familiar drawing.
Use the available time to understand the comparison, not to introduce every possible shadow effect. Multiple sources, tilted objects and broad lamps create different questions. This task isolates one screen movement under clearly stated conditions.
Plan a brief weekday return after the session. A new record can check whether the child explains the larger projection without claiming that the object grew. The worked distances should be covered so the answer is not simply recalled by position.
If your child says the object grew, ask where the task gives its width in each record. Return to the unchanged 2 cm object. Then ask what actually moved. This redirects attention while leaving the explanation for the child to build.
Also identify the distances carefully. Moving only the screen changes both its distance from the object and its distance from the source. That is not a second independent intervention; both changes follow from the same screen movement.
Keep the repair specific: ‘I treated the shadow width as the object width and ignored screen position.’ Do not require an unsupported exact-size prediction outside the measured records. A clear explanation of the supplied comparison is enough.
CHAPTER 7 OF 10 · Check fresh measurements
7. Try a changed record with a ratio trap
The independent check below changes the object size and distances between the worked and new tasks, but holds them fixed within the new comparison. Cover the worked case first. Ask which condition differs between the two fresh records.
Look for a reason that uses the fixed-object statement. Then check the numerical claim separately. A child can correctly identify screen movement while still assume that tripling one gap triples the shadow width.
If help is needed, record the exact prompt. That information can distinguish geometry-reading difficulty from a ratio shortcut. A later changed task tells the teacher more about transfer than an immediate rewrite after the complete explanation is supplied.
Independent check
In a fresh point-source paper model, the source and flat opaque object stay fixed 10 cm apart. The object stays 1 cm wide with unchanged orientation. The perpendicular screen is first 10 cm beyond the object, producing a 2 cm shadow, and then 30 cm beyond it, producing a 4 cm shadow. Only the screen moves. Did the object grow? Did tripling the object-to-screen gap triple shadow width? Explain using the supplied conditions and readings.
Checking notes
The object did not grow: its width is stated to remain 1 cm. The farther screen gives a larger projection in this model. The gap triples from 10 cm to 30 cm, but shadow width doubles from 2 cm to 4 cm, so the proposed tripling is incorrect. Source-to-screen distance also changes as a consequence of moving the screen.
CHAPTER 8 OF 10 · Check fresh measurements
8. Match the lesson rhythm to the actual PSLE stage
For the 2026 Standard PSLE Science syllabus, the paper lasts 1 hour 45 minutes. Booklet A has 30 multiple-choice questions worth 60 marks; Booklet B has 10–11 structured questions worth 40 marks. All are compulsory. Confirm the actual course and year rather than assuming this Standard format describes Foundation Science.
A programme title does not establish that the child’s examination is still ahead. Discuss the actual current school stage, including later-stage enquiries, without inventing a countdown. Future-year details should be checked against the applicable syllabus.
Use the planning table to compare attention and return opportunities in the real family week. This guide does not establish a Bendemeer venue, available slot, journey time or results promise. Confirm arrangements directly and judge progress through a fresh explanation that fits the setup.
| Learning need | Weekday possibility | Weekend possibility |
|---|---|---|
| Use feedback | Discuss the recent object-growth claim | Bring the marked setup and record |
| Separate positions | Focus on what moves and what stays fixed | Allow unhurried source–object–screen reading |
| Check transfer | Use changed distances another day | Plan a short weekday return |
| Match current stage | Confirm actual course and year | Apply the same course-and-year check |
Does a larger shadow prove the object grew? No. In the worked case, the object remains the same size while the screen moves farther away. The changed projection explains the larger shadow.
Does doubling the object-to-screen gap always double shadow width? Not in the supplied record: the gap changes from 20 cm to 40 cm, while shadow width changes from 4 cm to 6 cm. Do not substitute a guessed ratio for the measurements.
Is the same prediction guaranteed for every light source? No. This task specifies a small point-source model and controlled positions. Different source sizes, directions and arrangements should not be silently treated as identical.
CHAPTER 10 OF 10 · Plan the next step
10. Bring the setup and the measured change
Bring one marked light question and a changed screen-position check to the tuition discussion. Include the child’s explanation of what stayed fixed. Together, these can show whether the next step concerns reading conditions, projection geometry or avoiding unsupported numerical relationships.
In a 3-pax setting, each learner should identify the changed condition and explain the result before relying on the group. Discussion can help, but a shared correct shadow-size answer does not reveal whether every child checked the same conditions.
See Primary 6 PSLE Science tuition for programme information. Use the eduKate Singapore enquiry page to discuss the actual course, year, current work and family rhythm. Confirm arrangements directly and choose a schedule that supports precise reasoning and recall.
Chapter index ↑ · Previous chapter · Programme information →
For a wider comparison of lesson timing and recall, read the weekday versus weekend Science learning-rhythm guide.