Do You Know
Questions & Answers on General Knowledge.
What everyday household chemicals (cleaners, paints, detergents, etc.) contain large enough amounts of phosphor to glow under black light?
Fluorescent paints and many laundry detergents contain fluorescent chemicals-chemicals that absorb ultraviolet light and use its energy to produce visible light. Fluorescent paints are designed to do exactly that, so they certainly contain enough "phosphor" for that purpose. Detergents have fluorescent dyes or "brighteners" added because it helps to make fabrics appear whiter. Aging fabric appears yellowish because it absorbs some blue light. To replace the missing blue light, the brighteners absorb invisible ultraviolet and use its energy to emit blue light.
As a kid, we'd shake streetlights. They'd get real bright and then explode. Then we'd run away. Why'd they get brighter and explode?
What is the cause of the power "drop" in my house, that will intermittently (every 5 to 10 minutes) cause my lights to dim?
How do bicycle shocks and suspension affect the performance of a bicycle?
Why do people have to grow old?
Why is the sky blue?
What is net force?
Why do different sunglasses appear darker than others?
Why is the frictional force on a wagon's wheel in the opposite direction from the frictional force on a car's wheel?
Why do we say “either fish or cut bait” when we mean “make up your mind”?
What was the 4004?
Why, when getting serious, do we say, “Let’s get down to brass tacks”?
How did wakes become part of the funeral tradition?
How did Napoleon's reign end?
How does an infrared sensor faucet work?
Aren't dinosaurs from the Jurassic period in time?
How do thermals affect the atmosphere and air currents?
Why did the Mesopotamians build boats?
How do they split the first atom in an atomic bomb?
Why are dung beetles so called?
Why doesn't a helium balloon pop when it reaches the ceiling?
How are glacial valleys formed?
Why does the Moon follow us when we’re driving?
How does a light bulb work?
Were sauropods the only plant-eating dinosaurs?
Is a mile the same distance on land and at sea?
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