At the COMDEX computer expo in Las Vegas, Apple introduces the first line of PowerBook notebook computers, the PowerBook 100, PowerBook 140, and PowerBook 170. The first truly portable Macintosh, the PowerBook line redefined portable computing and set the bar for future laptop designs. For example, the PowerBooks were the first laptop to have a trackball positioned in front of the keyboard. Most existing PC laptops of the time ran DOS and were therefore keyboard-oriented, requiring the use of external mice.
Thomas Edison perfects the first commercially practical incandescent light bulb. Using a filament of carbonized cotton thread, his first attempt at this design results in a bulb that lasts about 13.5 hours before burning out. He later extends the life of the bulb to 40 hours. Edison’s successful design came only after he had tested over 6,000 different vegetable fibers during a span of over 18 months running 1,200 experiments and spending $40,000.