Benjamin Franklin created bifocals, lightning rods, flexible urinary catheters, odometers, the Franklin stove, and he mapped the Gulf Stream. Although Benjamin Franklin didn't discover electricity, he discovered different principles about electricity, including the fact that electricity consisted of a common element and was fluid in much the same way as a liquid.
Franklin's invention of bifocals stemmed from his own personal need for vision correction for his affliction with presbyopia. Franklin wrote in 1784 that his invention of double spectacles allowed him to see "distant objects as well as near ones" and that they made his eyes "as useful to me as ever they were."
Based on his work with elements of electricity, the single fluid theory was formed that states that electricity flows from a positive body to a negative one. Franklin also coined many of the terms that are associated with electricity, including the terms "plus," "minus," "conductor," "battery," "condensor" and "charge."
His work with electricity led Franklin to create the lightning rod, a device that would help protect homes from lightning's destructive force. The rod gives lightning an object to strike instead of striking the home and serves to protect homes from being burned down and prevent people inside from being electrocuted.