Category: PSLE Primary Science
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PSLE Science Reality Lab Vol No.428 | “Meets Drinking-Water Standards” — Does That Mean Every Contaminant Is Zero?
A student-facing PSLE Science Reality Lab guide to reading drinking-water compliance statements: standards, limits, sampling, non-zero results, reporting language and the boundary between evidence and overclaim.
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PSLE Science Reality Lab Vol No.427 | “24-Hour PSI = 100” — Is the Pollutant Concentration 100 µg/m³ Right Now?
A student-facing PSLE Science Reality Lab guide to separating Singapore’s 24-hour Pollutant Standards Index from pollutant concentrations, current 1-hour PM2.5 readings, averaging periods and physical units.
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PSLE Science Reality Lab Vol No.426 | “ISO 14001 Certified” — Does That Mean Every Product Is Environmentally Friendly?
A massive Primary 5/6 evidence guide to ISO 14001 certification: how to distinguish an organisation’s environmental management system and certified scope from claims that every product is green, impact-free or environmentally superior.
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PSLE Science Reality Lab Vol No.425 | “Verified Environmental Product Declaration” — Does That Prove the Product Is Environmentally Better?
A massive Primary 5/6 evidence guide to verified Environmental Product Declarations: why an EPD is a standardised, independently verified disclosure of life-cycle information, not a badge proving a product is environmentally superior.
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PSLE Science Reality Lab Vol No.424 | “N95” — Does 95 Mean It Blocks 95% of Every Airborne Particle in Every Use?
A massive Primary 5/6 evidence guide to the N95 marking: how to separate a NIOSH particulate filter-class test criterion from a universal guarantee about every particle, contaminant, face fit or real-world use.
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PSLE Science Reality Lab Vol No.423 | “4-Tick WELS Washing Machine” — Does Four Ticks Mean It Uses One Quarter as Much Water?
A massive Primary 5/6 evidence guide to Singapore’s WELS label: why four water-efficiency ticks are a category-specific grade under stated test conditions, not a literal promise that a washing machine uses one quarter as much water in every home.
