How much does a social worker make? According to the May 2012 records from the Bureau of Labor Statistics, the mean annual healthcare social worker salary is $51,460, or $24.74 per hour. The lowest ten percent earn $31,410, while the top ten percent make an average of $74,030 annually.
The Leibniz Step Reckoner. Gottfried Leibnizâs 1673 âStep Reckonerâ introduced a design innovation that enabled a single gear to represent any digit from 0 to 9 in just one revolution. This stepped-drum approach dominated calculator design for the next two centuries. Gottfried Leibniz.
Perrelet is considered the father of the automatic watch. He introduced the concept in 1770 and was way ahead of his time since the invention was better suited to wristwatches. Perrelet lived in the pocket watch era and, because the watches did not move much in pockets, the rotor system did not perform so well.