00:00:13long-lasting light that doesn’t burn up
00:00:14is the glass bulb and Paul Doherty of
00:00:17the exploratorium can proven this is a
00:00:21replica of a bulb from 1900 and it uses
00:00:24a carbon filament now when you put
00:00:27electricity through the carbon it glows
00:00:29incandescent makes light but it doesn’t
00:00:32melt and that’s the key incandescence is
00:00:36the emission of light from something hot
00:00:40carbon and tungsten have the strongest
00:00:42heat resistance of all elements most
00:00:46modern bulbs use tungsten filaments
00:00:48because it temperatures over 1800
00:00:50degrees they are much more durable
00:00:58what’s the role of the bulb these lights
00:01:01all have this case around them and that
00:01:04case the bulb protects the hot filament
00:01:07from the oxygen in the air creating an
00:01:10oxygen free zone within the bulb is the
00:01:13key to incandescent light this is what’s
00:01:16inside it’s the filament we saw in the
00:01:19clear glass bulb earlier and when I put
00:01:22electric current through it and it heats
00:01:24up the oxygen in the air will burn it so
00:01:28here it goes so I’m going to heat up the
00:01:31filament and as it gets hot enough it
00:01:33will begin to burn in the air
00:01:47to make bulbs glass has to be extracted
00:01:51from Sam here in the sim plots and pits
00:01:56of Southern Nevada they mine over 1
00:01:58million tons a year sand is the
00:02:07technical term used to describe rock
00:02:09which has been pulverized by the ocean
00:02:12or other types of erosion this cocktail
00:02:16of tiny grains is around seventy six
00:02:19percent silica four percent clay and
00:02:22twenty percent other impurities it’s the
00:02:26silica that’s needed to make clear glass
00:02:28for flashlight bulbs in nature
00:02:31translucent silica is seen in quartz
00:02:33crystals but turning pulverized quartz
00:02:37back into something you can see through
00:02:38is an epic journey
00:02:50around twenty six percent of this sand
00:02:52will become glass
00:03:06each of these trucks has enough sand to
00:03:09make 560,000 flash light bulbs
00:03:18to make glass sand is mixed with a few
00:03:22other key ingredients
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