by karen salazar. early forms of time- telling the sun sun-dial
TRANSCRIPT
WRIST WATCHES
• Small pocket watches, two to three inches in diameter, were available by the end of the nineteenth century.
• Mechanical wristwatches were an everyday item in the United States by the 1960s.
INVENTION OF THE “MICROCHIP”
• Microchip technology with quartz crystals
• Microchip is used to send signals to the dial of the watch
• Advantage: not a mechanical device w/ moving parts = does not wear out
RAW MATERIALS
• Made of modern materials; plastics and alloy metals
• Cases can be made of either plastic or metal
• Microchips: made of silicon
• LED: made of gallium arsenide
CITATIONS
http://bmwi.bimmerpost.com/forums/showthread.php?t=891519
http://www.madehow.com/Volume-1/Watch.html