When entrepreneurs used his invention to play music, Edison thought it was a debasement of his idea. Our widespread misunderstanding of inventors as setting out to solve society's problems causes us to say that necessity is the mother of invention. Actually, invention is the mother of necessity, by creating needs that we never felt before. (Be honest: did you really feel a need for your Walkman CD player long before it existed?) Far from welcoming solutions to our supposed needs, society's entrenched interests commonly resist inventions.
Medium-size dogs are at the midway point between tiny and massive canines, and both height and weight factor into the classification. Medium-size dogs generally weigh in the ballpark of 35 to 65 pounds, according to Kim Williamson of Animal Planet.. In terms of height, medium-size dogs are usually from 1 to 2 feet tall, measured from the ground to the withers or shoulder.
A good guideline to follow is: 1  Small breeds and dogs weighing less than 20 poundsâ7 years of age. 2  Medium breeds and dogs weighing 21 to 50 poundsâ7 years of age. 3  Large breeds and dogs weighing 51 to 90 poundsâ6 years of age.  Giant breeds and dogs weighing 91 pounds or moreâ5 years of age.