Category: Science
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PSLE Science Reality Lab Vol No.204 | “6 Air Changes per Hour” — Is Every Air Molecule Replaced Six Times?
A massive Primary 5/6 PSLE Science Reality Lab guide to air changes per hour: learn why 6 ACH is an equivalent ventilation rate based on airflow and room volume, not proof that every molecule is replaced six times or that a room becomes instantly contaminant-free.
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PSLE Science Reality Lab Vol No.203 | “12 °Brix” — Is the Drink Exactly 12% Sugar?
A massive Primary 5/6 PSLE Science Reality Lab guide to °Brix: learn why a refractometer reading is a soluble-solids or sucrose-equivalent measurement, not automatic proof that every complex drink contains exactly that percentage of sugar.
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PSLE Science Reality Lab Vol No.202 | “MERV 13 Filter” — Does 13 Mean It Captures 13% of Particles?
A massive Primary 5/6 PSLE Science Reality Lab guide to MERV ratings: learn why MERV 13 is a test-derived filter-performance category, not 13% capture, and how particle size, airflow, installation and room conditions limit the claim.
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PSLE Science Reality Lab Vol No.201 | “Heat-Pump COP = 3.5” — Did It Create 3.5 Units of Heat From 1 Unit of Electricity?
A massive Primary 5/6 PSLE Science Reality Lab guide to heat-pump COP: learn why COP 3.5 is a ratio of heating or cooling effect to work input, not energy creation, why operating conditions matter, and how to compare efficiency claims without confusing capacity, electricity use or seasonal performance.
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PSLE Science Reality Lab Vol No.200 | “Insulation R-Value = 4” — Does That Mean It Blocks Four Times as Much Heat?
A massive Primary 5/6 PSLE Science Reality Lab guide to insulation R-values: learn why R-4 is a thermal-resistance rating, not a percentage of heat blocked or a guarantee of four-times energy savings, and how to compare insulation claims fairly.
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PSLE Science Reality Lab Vol No.199 | “BOD₅ = 5 mg/L” — Does That Mean There Are 5 mg/L of Bacteria in the Water?
A massive Primary 5/6 PSLE Science Reality Lab guide to biochemical oxygen demand: learn why BOD₅ in mg/L reports oxygen used during a specified test, not the mass or count of bacteria, and how to evaluate water-quality claims without overreading the number.
