An airplane mechanic invented Slinky while he was playing with engine parts and realized the possible secondary use for the springs.
12
The oil used by jewelers to lubricate clocks and watches costs about $3,000 a gallon.
41
There's a Mumbai-based pizzeria that now delivers pizza by drone.
4
The first alarm clock could only ring at 4 a.m.
120
The electric chair was invented by a dentist!
122
First four countries to have television: England, the U.S., the U.S.S.R., and Brazil.
47
The first hard drive available for the Apple II had a capacity of only 5 megabytes.
46