Category: Science
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PSLE Science Reality Lab Vol No.362 | “Galaxy Redshift z = 2” — Does the Galaxy Look Twice as Red?
PSLE-SCI-REALITY-0362 A Galaxy Can Have a Huge Redshift Without Looking Like a Bright Red Dot An astronomy article says a distant galaxy has redshift z = 2. A learner imagines a colour slider: ordinary galaxy, red galaxy, twice-as-red galaxy. That is not what the number means. Astronomical redshift describes how identified features in light have…
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PSLE Science Reality Lab Vol No.361 | “High Signal-to-Noise Ratio” — Does a Cleaner Signal Prove the Measurement Is Accurate?
PSLE-SCI-REALITY-0361 The Cleanest Line on the Screen Can Still Be in the Wrong Place Two instruments measure the same reference signal. Instrument A produces a slightly fuzzy line centred on the correct value. Instrument B produces an extremely clean, sharp line—but the entire line is shifted away from the reference. Which instrument has the cleaner…
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PSLE Science Reality Lab Vol No.360 | “Tsunami Runup = 5 m” — Was the Offshore Wave 5 m Tall?
PSLE-SCI-REALITY-0360 The Line on the Hill Is Not the Height of the Wave at Sea After a tsunami, scientists survey a coast and find a water mark five metres above a stated reference sea level. A report calls the value “runup = 5 m”. A learner imagines a five-metre wall of water travelling across the…
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PSLE Science Reality Lab Vol No.359 | “Sea Ice Extent = 10 Million km²” — Is Every Square Kilometre Fully Covered by Ice?
PSLE-SCI-REALITY-0359 A White Map Can Count Open Water A science headline says: “Arctic sea ice extent: 10 million km².” A map underneath looks mostly white. A learner points at the number and says, “So there are 10 million square kilometres of solid ice.” That sounds reasonable until you ask a more careful question: What exactly…
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PSLE Science Reality Lab Vol No.358 | “Cloud Ceiling = 500 ft” — Are All the Clouds 500 ft Above the Ground?
A massive Primary 5/6 PSLE Science Reality Lab guide to cloud-ceiling reports: learn why a 500 ft ceiling means the lowest qualifying broken or overcast cloud base, not the height, top or thickness of every cloud.
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PSLE Science Reality Lab Vol No.357 | “Battery Specific Energy = 250 Wh/kg” — Does a 2 kg Battery Always Store 500 Wh?
A massive Primary 5/6 PSLE Science Reality Lab guide to battery specific energy: learn why Wh/kg is energy per unit mass on a stated cell, module or pack basis—not an automatic guarantee of total energy, power, range or runtime.
