Edison Perfects Light Bulb
October 21, 1879
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.
Triode Announced
October 20, 1906
Dr. Lee DeForest announces his three-element electrical vacuum tube, later known as a triode. The triode was able to produce a large voltage-amplifying effect, which when used to amplify weak signals, will make long-distance communication possible for the first time.
Apple Passes $500 Billion Valuation
February 29, 2012
The stock value of Apple, Inc. surpasses $500 billion, setting a new record for the company which was already the world’s most valuable company at the time. This day marks a milestone on the historic run for the company from near-bankruptcy in the 1990’s to one of the most, if not the most, dominant technology company in recent history. Apple would later become the first company in history to surpass $700 billion in value in February 2015.
Tokyo Skytree Completed
February 29, 2012
Construction of the Tokyo Skytree broadcast tower, delayed two months due to the 2011 Japan earthquake and tsunami, is completed on leap day – February 29th, 2012. The Tokyo Skytree is the tallest structure in Japan and the world’s tallest tower.