In 1827 – Mathematics student William Rowan Hamilton presented his “Theory of Systems of Rays” at the Royal Irish Academy in Dublin. It led to the development of the wave theory of light and led to the development of quantum mechanics.

In 1940 – A patent was granted to Herman Anthony for a leak-proof dry-cell battery. The patent was assigned to Ray-o-Vac.

In 2005 – At 8:27 PM, Jawed Karim, one of the co-founders of YouTube, uploaded the video “Me at the zoo” making it the first video ever to be uploaded to YouTube.

In 1592 – Wilhelm Schickard was born. He would grow up to create an early form of calculating machine called the “calculating clock”, that could add and subtract up to six-digit numbers.

In 1993 – NCSA Mosaic 1.0 was released, becoming the first web browser to achieve popularity among the general public.

In 2000 – The Big Number Change took place in the United Kingdom, changing how phone numbers were dialed in many areas. With the boom in mobile devices the UK had almost exhasuted all possible numbers, and needed the change to increase the pool of numbers to be assigned.

In 1962 – President John F. Kennedy opens the Seattle World’s fair by telephone from Palm Beach, Florida. He pressed a gold telegraph key which focused an antenna at Andover, Maine and a Navy radio telescope station in Maryland on a star to pick up a 10,000 year-old radio signal. That in turn set in motion various exhibits at the fair.

In 1964 – Satellite Transit-5BN-3 failed to reach orbit after launch. It dispersed 2.1 pounds (0.95 kg) of radioactive plutonium in its SNAP RTG power source.

In 1988 – Tandy Corp. held a press conference in New York to announce its plans to build IBM PS/2 clones.

In 1926 – Sam Warner approves the sound-on-disc system created by Western Electric and creates the Vitaphone company to develop the process to add sound to film.

In 1940 – Vladimir Zworykin and his team from RCA demonstrate the first electron microscope. It measured 10 feet high and weighed half a ton achieving a magnification of 100,000x.

In 1964 – The first AT&T picturephone transcontinental call was made between test displays at Disneyland and the New York World’s Fair.