The idea that squeezing crystals has electrical consequences is not new. A phenomenon called piezoelectricity, which is exploited in pressure sensors and quartz watches, involves creating a voltage between the ends of a piece of crystal by applying pressure.
The John Hancock Center was completed in 1970, and its gently sloping black steel form remains one of the most-recognizable structures in Chicagoâs famed skyline. John Hancock Center The John Hancock Center (centre building) on North Michigan Avenue in Chicago. Â© Chicago Architecture Foundation A bold form was chosen for the Hancock Center. The tapered rectangular tubeâwith giant trusses on each of the four sidesâreadily shows how the building is supported.
John Hancock was the first to sign the Declaration of Independence. He was president of the Continental Congress. He used large bold script and signed under the text in the center of the page. This is why, to this day, when you sign something it is called putting your John Hancock on it.