› added 6 years ago

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TIL, although many possible reasons have been proposed, some researchers believe the removal of lead from petrol was a key factor initiating a 20 year long fall in crime rates.

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via reddit.com

OoOj4 TIL that a device called a 'Teasmade' was popular in the 60s and 70s in the UK, an alarm clock which also made tea, ensuring it was ready upon waking up.
kOOxB TIL a teen injected himself with mercury at least three times in an attempt to convert his bones to metal after seeing X-Men Origins: Wolverine. He also had intentional multiple spider bites in the past after wanting to become Spider-Man.
XEGgP TIL that term 'patient zero' was coined by mistake during the 80's AIDS pandemic, when someone read Patient O (as in first recorded in US Outside California) wrongly
J0l TIL that the original and proper term actually is ‘duck tape’, as it was made for use by US GIs in WWII, who named it duck tape for its waterproofing abilities
oBj5Y TIL helicopter rotor blades spin at a fairly constant speed and only gain lift by altering the angle of the blades. The centrifugal force is too much to attempt to alter the blade RPM enough to generate lift.