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Darkness, color, mirror coatings and polarization all change how sunglasses look and feel. None of them tells you whether the lens blocks ultraviolet light.
The riskiest parts of Halloween are ordinary: a candle in a pumpkin on a doorstep, a costume that drags, a mask that blocks vision, and colored contact lenses bought without a prescription.
Magnification is capped by aperture, not the number printed on the box. What a Dobsonian trades for a GoTo mount, and the one rule for pointing any telescope at the Sun.
An unbalanced blank spun too fast can crack and leave the lathe. What matters on a beginner mini lathe: variable speed, a full face shield, and the tool rest.
A 20-watt diode engraver can fall in FDA’s highest laser hazard class. Eyewear only protects if its optical density matches the laser’s wavelength.
Sodium hydroxide burns eyes and skin on contact and heats up fast in water. What NIOSH, ATSDR and poison-center guidance says about PPE, mixing order and first aid.
